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Tire Pressure Poll
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It is poorly worded. I run 95 psi. There is no adequate answer since it's not 100 and also no less than 90...
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Re: Tire Pressure Poll [Trirunner] [ In reply to ]
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even better, I run 110 front and 90 back due to different wheel types(old school and fat arse)
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Re: Tire Pressure Poll [Trirunner] [ In reply to ]
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Clinchers
140 lbs
95 front
100 rear
Subtract 10 from each if it's wet
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Re: Tire Pressure Poll [Trirunner] [ In reply to ]
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Isn’t the bigger unaccounted-for variable the rim width for the PSI you are running???
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Re: Tire Pressure Poll [ In reply to ]
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130lb
Tubular
120psi front and back.

My bike mechanic put that much, it feels fast so I keep it that way.
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Re: Tire Pressure Poll [Trirunner] [ In reply to ]
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Trirunner wrote:
It is poorly worded. I run 95 psi. There is no adequate answer since it's not 100 and also no less than 90...

I ran 110 psi last weekend and will run 80 psi this coming weekend using the same tires. Very different road surfaces.
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Re: Tire Pressure Poll [s13tx] [ In reply to ]
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Josh's biggest point in regards to getting people to change their mindset in regards to pressure though is that people interpret road vibrations as fast. They're not. Smooth is fast. We have this idea of what fast should feel like but frankly its 100% wrong. I'm not sure exactly about the effect running tubular have but I promise you that pressure is not fast unless you only ride on a velodrome.

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Re: Tire Pressure Poll [Trirunner] [ In reply to ]
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Agreed. I have different wheel sets with different internal widths and difference size tires. I run any thing from 85 to 125. And 5psi less if I'm near race weight.
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Re: Tire Pressure Poll [jeffp] [ In reply to ]
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Hed jet9 black clinchers + latex tubes
85-90 PSI
I'm (158lbs-72kg)
Last edited by: Ksavostin: Aug 27, 19 20:40
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Re: Tire Pressure Poll [DFW_Tri] [ In reply to ]
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Yes, that too. As well as tube or tubeless...
Last edited by: Trirunner: Aug 27, 19 20:45
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Re: Tire Pressure Poll [s13tx] [ In reply to ]
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s13tx wrote:
130lb
Tubular
120psi front and back.

My bike mechanic put that much, it feels fast so I keep it that way.

Whoo! I hope you're runnin 20s!

808 > NYC > PDX
2020: Honu 70.3, CdA 70.3, NZ 70.3 WC
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Re: Tire Pressure Poll [Trirunner] [ In reply to ]
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80/85 tubeless
95/105 clincher
195 lbs
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Re: Tire Pressure Poll [FatandSlow] [ In reply to ]
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FatandSlow wrote:
Agreed. I have different wheel sets with different internal widths and difference size tires. I run any thing from 85 to 125. And 5psi less if I'm near race weight.

^^^^^^This

Too many unaccounted for variables.
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Re: Tire Pressure Poll [realbdeal] [ In reply to ]
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realbdeal wrote:
Josh's biggest point in regards to getting people to change their mindset in regards to pressure though is that people interpret road vibrations as fast. They're not. Smooth is fast.
Reminded of when in the early 90s a friend and I started riding fire roads on our road bikes (like gravel riding today!!). The first day we went down this super hectic descent - it seemed we were slamming it fast, bouncing all over the place.

12mph.


http://www.jt10000.com/
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Re: Tire Pressure Poll [jt10000] [ In reply to ]
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Road Bike Tubeless 28c - 80R 75F

Race bike Tube (not latex :D ) 25c 100R - 95F

TT Bike Tube (100% not latex) 23c 120R - 115F

Winter Bike Tube 32c 70R - 70F

Track Bike Tube 23c 140R- 140F

Fat Bike 3.8" Tubeless 8R - 7F

Turbo Bike N/A
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Re: Tire Pressure Poll [FatandSlow] [ In reply to ]
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FatandSlow wrote:
Agreed. I have different wheel sets with different internal widths and difference size tires. I run any thing from 85 to 125. And 5psi less if I'm near race weight.

Aren't those different sets for different purposes though? I also have a bunch of different wheels of different widths with different tires and different pressures. My winter training wheels are running 28s at ~75psi. But the poll question was specific to tri/TT racing, which 95% of the time for me means 23s at ~100psi.
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Re: Tire Pressure Poll [Trirunner] [ In reply to ]
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80F/85R. 23c Vittoria Corsa Speed on Hed Jet + Black. Tubeless. 165 lbs
Last edited by: tonyg420: Aug 28, 19 7:01
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Re: Tire Pressure Poll [Mario S] [ In reply to ]
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Mario S wrote:
TT Bike Tube (100% not latex) 23c 120R - 115F
Yikes. Latex vs butyl discussion aside, do you realize how much speed you're losing here? You could easily be running probably ~90 depending on your weight and have a more comfortable ride, and way less rolling resistance.

Benjamin Deal - Rookie Pro - Instagram - TriRig
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Most recent blog post: Takeaways from spectating Kona 2019
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Re: Tire Pressure Poll [rruff] [ In reply to ]
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The roads aren’t THAT different
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Re: Tire Pressure Poll [Trirunner] [ In reply to ]
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Trirunner wrote:
It is poorly worded. I run 95 psi. There is no adequate answer since it's not 100 and also no less than 90...

the poll is an exact repeat if a poll we ran here in january of 2017. had i gotten any feedback then i'd have changed the text. but if i want to show a comparative study i have to keep the text the same.

here's a preview, which i don't think will surprise you: 32 months ago 19 percent of you said you were running pressures of 120psi and higher. now it's 9 percent of you (as of this post). today, 37 percent of you say you're running pressures of 90psi or lower. back then it was 18 percent.

i think josh and tom a. and some of the other guys posting here have made an impact on you all.

Dan Empfield
aka Slowman
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Re: Tire Pressure Poll [realbdeal] [ In reply to ]
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realbdeal wrote:
Mario S wrote:
TT Bike Tube (100% not latex) 23c 120R - 115F

Yikes. Latex vs butyl discussion aside, do you realize how much speed you're losing here? You could easily be running probably ~90 depending on your weight and have a more comfortable ride, and way less rolling resistance.

If I wanted comfort I wouldn't ride a TT bike.

Thanks, but ill stick to my current pressures knowing that I am not losing any speed.
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Re: Tire Pressure Poll [Mario S] [ In reply to ]
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Mario S wrote:
realbdeal wrote:
Mario S wrote:
TT Bike Tube (100% not latex) 23c 120R - 115F

Yikes. Latex vs butyl discussion aside, do you realize how much speed you're losing here? You could easily be running probably ~90 depending on your weight and have a more comfortable ride, and way less rolling resistance.

If I wanted comfort I wouldn't ride a TT bike.

Thanks, but ill stick to my current pressures knowing that I am not losing any speed.
Woops. Forgot who I was responding to. Tradition for the sake of tradition and scientifically ignorant. Not worth any more responses.

Benjamin Deal - Rookie Pro - Instagram - TriRig
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Most recent blog post: Takeaways from spectating Kona 2019
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Re: Tire Pressure Poll [Trirunner] [ In reply to ]
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Train on gator skins. Race on GP 4000's. 120 PSI for both regardless of road conditions.
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Re: Tire Pressure Poll [Trirunner] [ In reply to ]
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130 lbs
TT bike: 700 x 25 @ 80psi
Road bike: 700 x 28 @ 70 psi
Gravel: 700 x 32 @ 60 psi
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Re: Tire Pressure Poll [Trirunner] [ In reply to ]
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Usually around 90 psi or so for training. 90-95 F/B with 5000's & latex on HED wheels for racing.


Blog: http://262toboylstonstreet.blogspot.com/
https://twitter.com/NateThomasTri
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Re: Tire Pressure Poll [Trirunner] [ In reply to ]
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Rim width, tire size, rider weight. There are so many variables here. The poll is oversimplified.
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Re: Tire Pressure Poll [realbdeal] [ In reply to ]
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Road Bike
Training wheels: HED Ardennes Plus, Challenge Paris Roubaix 27mm (w/ Vittoria latex tubes 25/28mm) - 75 psig

Race wheels: HED Jet Black, Vittoria Corsa G+ 25mm (w/ Vittoria Competition latex tubes 25/28mm) - 80 psig

Time Trial Bike
Race wheels: HED Jet SCT, Vittoria Corsa Speed G+ 23mm (w/ Vittoria Competition latex tubes 19/23mm) - 95 psig

I weigh 87 kg and run the supplied HED rim tape for all of my wheels. As well as Panaracer tire powder on the tubes, brushed on the inside of the tire casing, and onto the rim.
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Re: Tire Pressure Poll [Mario S] [ In reply to ]
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Mario S wrote:
realbdeal wrote:
Mario S wrote:
TT Bike Tube (100% not latex) 23c 120R - 115F

Yikes. Latex vs butyl discussion aside, do you realize how much speed you're losing here? You could easily be running probably ~90 depending on your weight and have a more comfortable ride, and way less rolling resistance.

If I wanted comfort I wouldn't ride a TT bike.

Thanks, but ill stick to my current pressures knowing that I am not losing any speed.

You're losing TONS of speed

-------------
Ed O'Malley
www.VeloVetta.com
VeloVetta is developing AERO cycling shoes with CFD and wind tunnel testing.
InstagramFacebook
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Re: Tire Pressure Poll [RowToTri] [ In reply to ]
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RowToTri wrote:
Mario S wrote:
realbdeal wrote:
Mario S wrote:
TT Bike Tube (100% not latex) 23c 120R - 115F

Yikes. Latex vs butyl discussion aside, do you realize how much speed you're losing here? You could easily be running probably ~90 depending on your weight and have a more comfortable ride, and way less rolling resistance.


If I wanted comfort I wouldn't ride a TT bike.

Thanks, but ill stick to my current pressures knowing that I am not losing any speed.


You're losing TONS of speed

He doesn't care. He clearly wants to go slow given his responses in the latex tube thread. That's fine for the rest of us so we can go faster on fewer watts than him though.
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Re: Tire Pressure Poll [ In reply to ]
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I have been training with mine from 100-110. Im 178lbs. Those are with butyl and some old Conti UltraSport IIs. When I race I switch over to latex and GP4000s. I have a race coming up and was thinking of putting them at 100, but now I'm not positive what pressure would be optimal. I can't even remember the road quality, but I guess I will ride out the day before to scope it out, but what would the suggestion depending on smooth roads vs some bumpier asphalt?

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Re: Tire Pressure Poll [hadukla] [ In reply to ]
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hadukla wrote:
s13tx wrote:
130lb
Tubular
120psi front and back.

My bike mechanic put that much, it feels fast so I keep it that way.


Whoo! I hope you're runnin 20s!

22 front & 25 rear
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Re: Tire Pressure Poll [AlyraD] [ In reply to ]
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AlyraD wrote:
I have been training with mine from 100-110. Im 178lbs. Those are with butyl and some old Conti UltraSport IIs. When I race I switch over to latex and GP4000s. I have a race coming up and was thinking of putting them at 100, but now I'm not positive what pressure would be optimal. I can't even remember the road quality, but I guess I will ride out the day before to scope it out, but what would the suggestion depending on smooth roads vs some bumpier asphalt?

What width GP4k do you run? And what wheel? With latex you can go a smidge lower than usual. At your weight if you are running 23mm (guessing) you might even do better at 95psi.


Personally I run 25mm Conti GPTTs with latex on ENVE 7.8s at 80psi. I weigh 150lbs.
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Re: Tire Pressure Poll [g_lev] [ In reply to ]
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g_lev wrote:
[He clearly wants to go slow given his responses in the latex tube thread. That's fine for the rest of us so we can go faster on fewer watts than him though.
Ringy Dingy. Hello. Yes, this is the 1980s. I want my tire pressure back.
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Re: Tire Pressure Poll [DFW_Tri] [ In reply to ]
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DFW_Tri wrote:
The roads aren’t THAT different




Last edited by: rruff: Aug 28, 19 7:31
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Re: Tire Pressure Poll [exxxviii] [ In reply to ]
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I guess it never really occurs to some of you that people actually do their own testing.

Like really world testing

Actual sitting on a bike testing.

Not keyboard warrior marketing BS im only 14 years old kind of testing!!!

Doesn't occur to anyone that there are many factors when choosing a tyre pressure?

Oh well!!

For clarity, 1980's it would be tubs and 160psi!! :D
Last edited by: Mario S: Aug 28, 19 7:31
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Re: Tire Pressure Poll [g_lev] [ In reply to ]
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I have Novatec r5s and the 4000s are 25s.

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Re: Tire Pressure Poll [rruff] [ In reply to ]
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The issue with citing a graph like that and then saying you're running 110 though is that the cost of running too high is clearly much worse than the potential loss of running too low. From that bottom graph, running at 100 is without a doubt the right move even if you think the asphalt is nearly perfect. At the worst case, you lose 1 watt if it really is perfect the whole way. The worst case of running 110 even is that you lose 6 watts as soon as there is any section of bad pavement. Its simply safer to err on the side of too low rather than too high. And 110 is almost always going to be erring on the side of too high if not being outright too high.

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Deals on Wheels - Race reports, pictures, sponsors, and more!
Most recent blog post: Takeaways from spectating Kona 2019
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Re: Tire Pressure Poll [s13tx] [ In reply to ]
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s13tx wrote:
130lb
Tubular
120psi front and back.

My bike mechanic put that much, it feels fast so I keep it that way.


Way too high.

Take a minute to adjust the pressure.
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Re: Tire Pressure Poll [Trirunner] [ In reply to ]
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I've run as low as 20 on the mtb, 22 on cx, 75 on the roadie, TT and 110 on the trackie. I've also gone all the way up to 220 with on the track, so the best answer for this might be "it depends".

Growing up it was always 120 PSI. It was grilled into me to check before every ride, more recently, I've been playing around with 75-85 PSI and while I have no idea if its faster or not, I like it. I think 75 is a touch soft at 156-160 lbs but that could also just be in my head from years of riding at 100-120.
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Re: Tire Pressure Poll [Trirunner] [ In reply to ]
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Agree with many of the points on here that it varies depending on tire size, rim type, road conditions, etc. I'm 175

On my TT bike, I have old school narrow rims with 23mm GP4ks and Latex tubes. I run about 90-95 depending on conditions and road surface- 95 is only a on very smooth surface (a weekly TT series near where I live uses such a road, would be about 90 on normal roads).

On my road bike, I have Jet 6's with 25mm GP4ks (which actually measure at 30mm on the rim). I barely get over 80PSI, and will run less depending on the application. For example, I ran 70PSI in a recent technical crit to increase grip, and had no issues even with some nasty bumps. The lower pressure really helped through a couple fast and rough corners.

Anyone running north of 90PSI is likely giving up a lot of speed, unless you have old school narrow tires and rims, and/or are only riding on pristine pavement.
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Re: Tire Pressure Poll [jimatbeyond] [ In reply to ]
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jimatbeyond wrote:
s13tx wrote:
130lb
Tubular
120psi front and back.

My bike mechanic put that much, it feels fast so I keep it that way.


Way too high.

Take a minute to adjust the pressure.

I will go out for a long ride, adjust the pressure as I ride and see. We have a 10 mile loop around the lake so I can come back to my car to adjust air pressure anytime. Thank you!
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Re: Tire Pressure Poll [cartsman] [ In reply to ]
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cartsman wrote:
FatandSlow wrote:
Agreed. I have different wheel sets with different internal widths and difference size tires. I run any thing from 85 to 125. And 5psi less if I'm near race weight.


Aren't those different sets for different purposes though? I also have a bunch of different wheels of different widths with different tires and different pressures. My winter training wheels are running 28s at ~75psi. But the poll question was specific to tri/TT racing, which 95% of the time for me means 23s at ~100psi.

Thanks for pointing out the tri-tt part. Missed that. In addition to fat and slow, I'm getting old and blind.

In that case, 115psi front, 120 rear, 23mm tubulars.
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Re: Tire Pressure Poll [FatandSlow] [ In reply to ]
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Gooooo loooower! Drop them to 95 and then ride some. Drop them to 90 and ride some more. You are losing out on a lot of speed and comfort as an added bonus.

Benjamin Deal - Rookie Pro - Instagram - TriRig
Deals on Wheels - Race reports, pictures, sponsors, and more!
Most recent blog post: Takeaways from spectating Kona 2019
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Re: Tire Pressure Poll [realbdeal] [ In reply to ]
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realbdeal wrote:
The issue with citing a graph like that and then saying you're running 110 though is that the cost of running too high is clearly much worse than the potential loss of running too low. From that bottom graph, running at 100 is without a doubt the right move even if you think the asphalt is nearly perfect. At the worst case, you lose 1 watt if it really is perfect the whole way. The worst case of running 110 even is that you lose 6 watts as soon as there is any section of bad pavement. Its simply safer to err on the side of too low rather than too high. And 110 is almost always going to be erring on the side of too high if not being outright too high.

You assume a lot...

The asphalt was very good, and most of the time I was on the white line which was super smooth.
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Re: Tire Pressure Poll [Slowman] [ In reply to ]
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For years I was running 115/120 psi with my stock Felt TTR wheels/Conti GP4000S 25mm tires (195 lb rider) but when I bought my HED Jet 6 Plus wheels they recommended something in the neighborhood of 87 psi. I think their max. was stated at 90 psi. I consulted them and they said their testing showed running those lower pressures was optimum performance wise and who was I to disagree. But running right there for the last couple years without issues.

2020: IMSG | IM70.3 Des Moines |
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Re: Tire Pressure Poll [s13tx] [ In reply to ]
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In a thread that you started recently, you said that you were very concerned about getting a flat.

Why is that?
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Re: Tire Pressure Poll [Trirunner] [ In reply to ]
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Why is tire pressure always addressed as 'run' or 'ran'?
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Re: Tire Pressure Poll [realbdeal] [ In reply to ]
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This. I used to run about 110 on 25mm Conti 4000s (tubes). Same tires/size, now I generally race and train at 90psi, and I'm significantly faster. For reference, my weight generally falls from low 150s (race weight) to up to 160 (post A-race sloth period weight). Added bonus is I don't have to worry about my tires exploding on a hot day.
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Re: Tire Pressure Poll [jimatbeyond] [ In reply to ]
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jimatbeyond wrote:
In a thread that you started recently, you said that you were very concerned about getting a flat.

Why is that?


It’s because I’ve never replaced tubular tires during the race or bike rally. Not to mention, I don’t carry a spare tubular tire. I have a road bike with clinchers and yes I have no problem replacing inner tubes and tires on that one. I carry PitStop as a repair kit for tubulars. I used it once and it worked well but I’m afraid I’m going to get a big cut that PitStop can’t fix.
Last edited by: s13tx: Aug 28, 19 8:44
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Re: Tire Pressure Poll [g_lev] [ In reply to ]
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g_lev wrote:
AlyraD wrote:
I have been training with mine from 100-110. Im 178lbs. Those are with butyl and some old Conti UltraSport IIs. When I race I switch over to latex and GP4000s. I have a race coming up and was thinking of putting them at 100, but now I'm not positive what pressure would be optimal. I can't even remember the road quality, but I guess I will ride out the day before to scope it out, but what would the suggestion depending on smooth roads vs some bumpier asphalt?


What width GP4k do you run? And what wheel? With latex you can go a smidge lower than usual. At your weight if you are running 23mm (guessing) you might even do better at 95psi.


Personally I run 25mm Conti GPTTs with latex on ENVE 7.8s at 80psi. I weigh 150lbs.

just tacking on as I'm in a similar situation. I'm about 170lbs. Currently running GP4000s 25mm but might be switching to GP5000s (not sure how much that matters) with latex. I've been running at 90psi front and back for maybe a year. Not sure if I should go as low as 85psi or leave as is. wheels are the profile design 58/twenty fours internal rim width is 17mm and external is 24.5mm.
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Re: Tire Pressure Poll [s13tx] [ In reply to ]
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Do you glue the tires to your rims?

Why don't you carry a spare tire?
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Re: Tire Pressure Poll [s13tx] [ In reply to ]
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s13tx wrote:
It’s because I’ve never replaced tubular tires during the race or bike rally. Not to mention, I don’t carry a spare tubular tire. I have a road bike with clinchers and yes I have no problem replacing inner tubes and tires on that one. I carry PitStop as a repair kit for tubulars. I used it once and it worked well but I’m afraid I’m going to get a big cut that PitStop can’t fix.

This is why I sold my tubulars

Going really far really slow - it doesn't matter how fast you finish, all that matters is that you finish
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Re: Tire Pressure Poll [] [ In reply to ]
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I am about 190lbs running a 23mm GP5000 on the front and 25mm GPTT on the rear. I go 100psi on the front and 95psi in the rear. I don't flat a ton, but it seems like most of my flats are pinch flats. I would like to go lower, but I am afraid to because of pinch flats. Should I be?
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Re: Tire Pressure Poll [TennesseeJed] [ In reply to ]
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TennesseeJed wrote:
I am about 190lbs running a 23mm GP5000 on the front and 25mm GPTT on the rear. I go 100psi on the front and 95psi in the rear. I don't flat a ton, but it seems like most of my flats are pinch flats. I would like to go lower, but I am afraid to because of pinch flats. Should I be?

I'm about your weight and I use 23's front and rear (GP4K's). I have been riding around 85 psi for a couple of years with no problems on HED plus wheels

the world's still turning? >>>>>>> the world's still turning
Last edited by: Callin': Aug 28, 19 10:02
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Re: Tire Pressure Poll [s13tx] [ In reply to ]
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s13tx wrote:
hadukla wrote:
s13tx wrote:
130lb
Tubular
120psi front and back.

My bike mechanic put that much, it feels fast so I keep it that way.


Whoo! I hope you're runnin 20s!


22 front & 25 rear

Well then I hope you're in my age group. Mario S too but he's way worse off, it seems.

808 > NYC > PDX
2020: Honu 70.3, CdA 70.3, NZ 70.3 WC
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Re: Tire Pressure Poll [s13tx] [ In reply to ]
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YIKES! I hope this is for velodrome racing?


s13tx wrote:
130lb
Tubular
120psi front and back.

My bike mechanic put that much, it feels fast so I keep it that way.
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Re: Tire Pressure Poll [TH3_FRB] [ In reply to ]
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TH3_FRB wrote:
YIKES! I hope this is for velodrome racing?


s13tx wrote:
130lb
Tubular
120psi front and back.

My bike mechanic put that much, it feels fast so I keep it that way.

Nope! On the street with pot holes, Chip seal, concrete and asphalt.
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Re: Tire Pressure Poll [s13tx] [ In reply to ]
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Did Mario S put you up to this?


s13tx wrote:
TH3_FRB wrote:
YIKES! I hope this is for velodrome racing?


s13tx wrote:
130lb
Tubular
120psi front and back.

My bike mechanic put that much, it feels fast so I keep it that way.


Nope! On the street with pot holes, Chip seal, concrete and asphalt.
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Re: Tire Pressure Poll [Mario S] [ In reply to ]
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Mario S wrote:
realbdeal wrote:
Mario S wrote:
TT Bike Tube (100% not latex) 23c 120R - 115F

Yikes. Latex vs butyl discussion aside, do you realize how much speed you're losing here? You could easily be running probably ~90 depending on your weight and have a more comfortable ride, and way less rolling resistance.


If I wanted comfort I wouldn't ride a TT bike.

Thanks, but ill stick to my current pressures knowing that I am not losing any speed.

Are you racing 75+ and still reading Bicycling Magazine? Your stubbornness certainly implies so.

I feel like this whole thread is just a troll of the willfully ignorant.

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Re: Tire Pressure Poll [realbdeal] [ In reply to ]
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Question for you, Ben. I watched your video on tire pressure and downloaded the app you talked about before age group nats, because I was curious and the roads there weren’t as smooth as they advertised. I’m pretty consistently around 49-50 kg and it recommended I run less than 80 psi for both the front and back. I’ve run 110-115 psi pretty much the entire 6 years I’ve been in the sport. Now I’m running more like 100-105 for race day. I have 23 mm Conti GP400s on both my road and Tri bikes. I’ve ridden with my tires in the 70s-80s before (on accident) and I wasn’t a fan. It felt slow, especially going up hills. Suggestions?
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Re: Tire Pressure Poll [s13tx] [ In reply to ]
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Silca published a series of blogs in which they look at the relationship between pressure, road surface, and Crr. Unfortunately, the blog is still there, but I think all of the image links are broken. The startling finding was that there are two dynamics at play that intersect to show a critical pressure inflection point. Impedance Crr increases sharply with pressure, but it starts out lower than steady state Crr. However, when you reach that inflection point on a rough surface, like chip seal, then you will radically increase Crr due to surface impedance losses.

In their chart, the roughened concrete inflection point was at around 70 PSI, and I think the rougher asphalt point (chip seal) was around 100 PSI.
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Re: Tire Pressure Poll [realbdeal] [ In reply to ]
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Appreciate your point of view, but not at my weight (210) and not on 23mm tubulars. Race weight is 185. 115/120 is down from130/135 back in the day - and the lower pressure is faster. 110/115 was not. 105/110 was slower too, so I stopped testing.

I run 85 on the front of my Belgium C+ and Jet 6+ and 90 on the rear with 25mm GP4kS2s. I also run 105/110 f/r on my old Reynolds Assaults with 23mm Michelins.
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Re: Tire Pressure Poll [HeartRN] [ In reply to ]
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HeartRN wrote:
Question for you, Ben. I watched your video on tire pressure and downloaded the app you talked about before age group nats, because I was curious and the roads there weren’t as smooth as they advertised. I’m pretty consistently around 49-50 kg and it recommended I run less than 80 psi for both the front and back. I’ve run 110-115 psi pretty much the entire 6 years I’ve been in the sport. Now I’m running more like 100-105 for race day. I have 23 mm Conti GP400s on both my road and Tri bikes. I’ve ridden with my tires in the 70s-80s before (on accident) and I wasn’t a fan. It felt slow, especially going up hills. Suggestions?

Lets keep in mind that I am by no means an expert on this topic. I just seek out all expert opinions, research, and data and come to conclusions based on that.

Realistically the only difference between me and Mario S is a willingness to trust the science. And youth. And speed. And good looks.

Seriously though, I appreciate the skepticism and/or concerns of running lower tire pressures. Like you, when I saw how low it suggested I run my tires on that app (75/77), I couldn't bring myself to do it and ran 85 instead (knowing the pavement was in pretty good condition). The interesting thing about your observations about how you felt (slow, probably squishy?), is that that's exactly what we need to train our mind to believe is fast. Because it is. We're so used to feeling the vibrations of the road and thinking that's fast because that's how its always been. Instead we need to start telling ourselves that smooth is fast. My approach to this has been to slowly work my pressure down to the point where the right PSI feels "normal". Maybe try lowering your pressure by 5psi each week until you hit at least 85 or something. Realistically your ideal is something lower than that, but 85 will certainly be better than 100. Now I ride my trainer for 4 out of 5 workouts, but when I decided to take this low pressure leap, I would force myself outside for short rides more often just to get a better understanding of how it felt. Ultimately, for most of us right now, it comes down to being willing to trust the science more than we trust our bodies. That's super hard.

Benjamin Deal - Rookie Pro - Instagram - TriRig
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Last edited by: realbdeal: Aug 28, 19 13:34
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Re: Tire Pressure Poll [mjbruiser] [ In reply to ]
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mjbruiser wrote:
Train on gator skins. Race on GP 4000's. 120 PSI for both regardless of road conditions.

I ride on these types of tires and put 120psi in them. Maybe I'm doing it wrong - idk. But, I read that rolling resistance was lower on these at 120psi.

https://www.strava.com/...tes/zachary_mckinney
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Re: Tire Pressure Poll [plant_based] [ In reply to ]
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plant_based wrote:
mjbruiser wrote:
Train on gator skins. Race on GP 4000's. 120 PSI for both regardless of road conditions.


I ride on these types of tires and put 120psi in them. Maybe I'm doing it wrong - idk. But, I read that rolling resistance was lower on these at 120psi.

If that's the case, after all this time, I don't care to be right.
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Re: Tire Pressure Poll [realbdeal] [ In reply to ]
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I appreciate the advice! As a nurse I’m kind of used to the whole “you gotta trust the science,” so I trust that you’ve legitimately done your research. I ride my trainer for the majority of workouts too due to time constraints, but I like the idea of lowering the pressure 5 psi each time.
Considering the roads sucked in Cleveland I probably should have ridden lower than 100 since my body (shoulders especially) seemed to absorb most of the shock of the pavement (bad enough that when we drove the roads my car was taking the bumps just as poorly), but I couldn’t bring myself to.
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Re: Tire Pressure Poll [HeartRN] [ In reply to ]
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For sure! If you want to get any of this info straight from the source, I'll do some plugging for Josh @ Silca's podcast: Marginal Gains. I'm not a podcast person but I've listened to every one of these. Josh really does a great job of condensing complicated engineering into understandable, applicable advice. Tire pressure pretty much gets brought up in every episode but there are a few that are more focused on it: the 'asymmetry' episode, 'contact points', and without fail every 'ask josh anything' episode. Worth listening to all of them though.

Benjamin Deal - Rookie Pro - Instagram - TriRig
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Re: Tire Pressure Poll [mjbruiser] [ In reply to ]
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Re: Tire Pressure Poll [Trirunner] [ In reply to ]
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200lbs

100/105 on Training Wheels, Mavic Askium
90/95 on Race Wheels, HED JET6+

Rugby Media Dude-earfulofdirt.com

Hooker training for the Sport of Scrum-Halves [Triathlon]
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Re: Tire Pressure Poll [realbdeal] [ In reply to ]
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realbdeal wrote:

Realistically the only difference between me and Mario S is a willingness to trust the science. And youth. And speed. And good looks.

That's nice. 👍

Amazing insite to someone you lnow the square root of Jack about.

Classy
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Re: Tire Pressure Poll [Mario S] [ In reply to ]
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Mario S wrote:
realbdeal wrote:


Realistically the only difference between me and Mario S is a willingness to trust the science. And youth. And speed. And good looks.


That's nice. 👍

Amazing insite to someone you lnow the square root of Jack about.

Classy

Nice work editing out my pink? You're right though, the only statement I know is correct is the first. The rest was a pretty obvious joke. I have literally zero problems with people doing suboptimal things speed wise. I do have problems with people straight up disputing hard science AND acting like everyone who adheres to said science is an idiot.

Benjamin Deal - Rookie Pro - Instagram - TriRig
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Last edited by: realbdeal: Aug 28, 19 14:39
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Re: Tire Pressure Poll [plant_based] [ In reply to ]
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plant_based wrote:
mjbruiser wrote:
Train on gator skins. Race on GP 4000's. 120 PSI for both regardless of road conditions.


I ride on these types of tires and put 120psi in them. Maybe I'm doing it wrong - idk. But, I read that rolling resistance was lower on these at 120psi.

Gatorskins at 120psi? Sounds downright miserable. Back that off at least 30 lbs. Better yet, throw the Gatorskins in the trash and ride something with at least a modicum of suppleness.


I'm a 195 lbs. On the tri bike, I run 24c GP Force (F&R) with latex tubes mounted on 18c rims @ 90-95psi.

On the road bike, I over-tire a set of 15c rims with 28c Vittoria Corsas and latex tubes filled to ~80-85psi. Old-school thinking would suggest that a fatty like me riding fat tires on skinny rims at that pressure is a recipe for pinch-flats, but , knock on wood, I've made it all season without any flat on either bike.




plant_based wrote:

https://www.bicyclerollingresistance.com/...grand-prix-5000-2018

Rolling resistance is lower on GP4000IIs and GP5000 at 120psi

If you're riding on a steel diamond plate road. Real roads are generally constructed of a material with dramatically different properties, and the surface imperfections are far less uniform.



"They're made of latex, not nitroglycerin"
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Re: Tire Pressure Poll [gary p] [ In reply to ]
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Re: Tire Pressure Poll [realbdeal] [ In reply to ]
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What's the app? Who's data are they using?

-------------
Ed O'Malley
www.VeloVetta.com
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Re: Tire Pressure Poll [RowToTri] [ In reply to ]
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RowToTri wrote:
What's the app? Who's data are they using?
Sram/Quarq's Tyrewiz app. Ignores a lot but it's a good place to start.

Benjamin Deal - Rookie Pro - Instagram - TriRig
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Re: Tire Pressure Poll [plant_based] [ In reply to ]
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That is out of date-- or rather the thinking that higher-is-better is out of date. Those types of analyses only factor static casing losses and ignore impedance losses. They are good for comparing different products, but not for determining best pressure for the anticipated road surface.

Check this out: https://blog.silca.cc/...stance-and-impedance
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Re: Tire Pressure Poll [rruff] [ In reply to ]
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rruff wrote:
DFW_Tri wrote:
The roads aren’t THAT different




Please tell me if I read this right... from the 2nd graph... I'm on ok-to-rough ashphalt mostly (rare to have concrete road surfaces where I live... and rarer to have nice new asphalt either - last time I saw some of that was when TdF visited Yorkshire and Derbyshire and miraculously some new surfaces appeared over Beirut-bomb-cratered roads over the Strines 😁).
I'd read it as being best off around 90-100psi.
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Re: Tire Pressure Poll [exxxviii] [ In reply to ]
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I am in awe of those that do take up the battle to attempt to educate those who do not comprehend...I have neither the time nor the energy.


However, I do have data from doing my own field testing several years ago with multiple, multiple loops at various tire pressures. I was quite surprised that I was indeed faster on normal, older New England roads (asphault/chipseal) at lower pressures.

I'm a science guy (*ie evidence based) and Josh's data proved all I needed to know/confirm. Now, how to tell how bad the composite road surfaces are at various venues to appropriately lower the pressure to the 'optimal' on race day-hmmmmm. Someone please, please post THAT.



Carry on and good luck...
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Re: Tire Pressure Poll [BobAjobb] [ In reply to ]
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Potentially. And that's where your own weight and such comes in to it. But also consider this: if you decide to run 80psi you're losing max 1-2 watts regardless of the road surface AND you get a more comfortable ride. At 100 or even 90 as soon as you hit extra bad surface you're losing more than the 1-2 watts. So it's probably net even to run lower and you get increased comfort.

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Re: Tire Pressure Poll [realbdeal] [ In reply to ]
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You got me thinking on this (which I try not to do...it just seems to hurt the ballclub, lol): I did ST.G 70.3, as did you, which is why I'd like to add this little tid bit in, and as to why you got me thinking. I am no "real" triathlete, but I don't completely suck (2:50 on the bike, but lost time...which is why i'm posting).

I'm 200lbs (not fat). I run my tires up at 110psi (GP4000, 23mm, Flo 60/90 combo). I was always of the "hard is fast" mentality. And I thought the roads of St.G were nice and smoooooth, so this would be a good thing. But that was not the case (or maybe it was and I'm completely wrong). I thought the St.G course was ROUGH AF!! Not horrible, but I felt EVERY.SINGLE.CRACK. And to that point I remember thinking "fuck, my back and shoulders are tired because I have to absorb and take every bump and hold on in aero", to the point that the last stretch into town I was flying 40+mph...and all those little ridges from the expansion cracks that have been sealed were being significantly felt in my body. And then it happened: a bumpy stretch (didn't look bumpy) and my chain got thrown.

So all this talk of the bumps and the up and down and lighter PSI got me thinking: pretty sure I need to drop that PSI a bit and maybe that won't make the ride suck so bad, and maybe those bumps won't be felt (rolled over, instead of pushing the bike up as I go over) as much so my chain doesn't get thrown. Just got me thinking because I know a lot really like the St.G roads...but I thought they sucked...and maybe that is because I was running such a high PSI (in Butyls if that matters, but will be in latex from now on).
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Re: Tire Pressure Poll [BobAjobb] [ In reply to ]
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BobAjobb wrote:



Please tell me if I read this right... from the 2nd graph... I'm on ok-to-rough ashphalt mostly (rare to have concrete road surfaces where I live...I'd read it as being best off around 90-100psi.


Yes, assuming the bike-and-rider combined weight is ~same as the test (190lbs/86kg), you're on the same tires (25c GP4000S) mounted on similar internal width wheels (test wheels were Zipp 404 Firecrests, 16.5mm).

Change any one parameter (weight, tire, wheel width, surface) and the graph is going to change. Whatever the trace, t's better to error on the side of low than high, as the slope is steeper past the impedance inflection point.

"They're made of latex, not nitroglycerin"
Last edited by: gary p: Aug 28, 19 15:55
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Re: Tire Pressure Poll [JMike] [ In reply to ]
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JMike wrote:
Why is tire pressure always addressed as 'run' or 'ran'?

Everyone here says they are “running” this or that for anything. Can’t stand that.
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Re: Tire Pressure Poll [SBRmd] [ In reply to ]
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SBRmd wrote:
JMike wrote:
Why is tire pressure always addressed as 'run' or 'ran'?


Everyone here says they are “running” this or that for anything. Can’t stand that.
Cyclists go super slow when they run Marathons!
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Re: Tire Pressure Poll [SBRmd] [ In reply to ]
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SBRmd wrote:
JMike wrote:
Why is tire pressure always addressed as 'run' or 'ran'?

Everyone here says they are “running” this or that for anything. Can’t stand that.

Don’t know you but I like your thinking
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Re: Tire Pressure Poll [realbdeal] [ In reply to ]
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realbdeal wrote:

We're so used to feeling the vibrations of the road and thinking that's fast because that's how its always been. Instead we need to start telling ourselves that smooth is fast. My approach to this has been to slowly work my pressure down to the point where the right PSI feels "normal".
Ultimately, for most of us right now, it comes down to being willing to trust the science more than we trust our bodies. That's super hard.

I was thinking about this statement and it hold water for me. 'Feeling normal' or even 'comfortable but slow' may be the goal because smooth is fast.
That is something I believe.

Smooth is fast. Yessssir. I like the way you think, Ben.

(*I found the link to what I posted on BT back in 2016)
https://beginnertriathlete.com/...id=542235&page=1


edited to add:
my 70.3 PR (bike and OA) was from IMAC in 2018-and I 'ran'/used 80/80 on race day-front 23/back-25; Zipp 808/conti 4000's both: with light rain and cool temps that day. Weight distribution 45/55% by scales x 2.


It got me to Worlds, so I'm not complaining or questioning the logic too much
Last edited by: dtoce: Aug 28, 19 17:23
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Re: Tire Pressure Poll [plant_based] [ In reply to ]
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plant_based wrote:
https://www.bicyclerollingresistance.com/...grand-prix-5000-2018

Rolling resistance is lower on GP4000IIs and GP5000 at 120psi

resistance is lower, with every tire, every width, at the highest pressure tested. the prevailing thinking is that the testing equipment does not incorporate elements in actual road riding - the way the rider and his weight react on the tire, the way the road reacts to the tire - so doesn't generate an accurate picture of what pressure is best. what it lacks in accuracy it makes up for in precision, that is, it can identify very small changes in energy required to turn the drum at speed (or however the thing works).

Dan Empfield
aka Slowman
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Re: Tire Pressure Poll [realbdeal] [ In reply to ]
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Interesting - they seem to be in the lower pressure camp. I posted this in another thread but maybe I should have posted it here:

Some of the information out there on tire pressures seems to be conflicting.

Here is Roval's recommendation (I run a Roval CLX 64 front wheel)


Here is HED's recommendation (I run a Jet Disc Plus on the rear)


My 23c GP5000 tire measure 26mm at 85 psi on my front wheel. Roval does not say if it's chart is for measured or labeled tire widths, but it would recommend >107psi if labeled, 89 if measured. HED's chart is for labeled width so they recommend 72 psi. Quite a huge difference! What is one to do? They cannot both be right.

On the rear, I've been running a 23C GPTT which actually measures 27.75mm on my HED Jet Disc Plus! I'm re-thinking that tire right now, given the 25mm brake track on that wheel, but the aerocoach testing puts it ahead of the GP5000 on their wheel - need to get the width of that wheel. At least in the back it's shrouded.



From Silca's website, I cannot find a chart with enough data to really select a pressure given tire width and rider weight, but there is this, which seems to suggest even higher pressures than roval, but we do not know rider weight:


Here's a chart from Flo (They apparently got it from TomA) which I'm pretty certain refers to measured width and recommends about the same as roval, ~90.


My inclination is to go with the Flo(TomA)/Roval recommendations since they agree, and Tom does a solid job in this testing.

Is there a better source that I am missing?

-------------
Ed O'Malley
www.VeloVetta.com
VeloVetta is developing AERO cycling shoes with CFD and wind tunnel testing.
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Re: Tire Pressure Poll [rruff] [ In reply to ]
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Ingles, por favor.
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Re: Tire Pressure Poll [Trirunner] [ In reply to ]
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Ditto and ditto.

I used to run 120, basically the max.
That was like 15+ years ago.
Then was at 115 for a while.
Then was running 105 for a few years.
Now I’m typically at 95.

Tires went from Michelin ProRace to those Bongtager Rwhatever’s that were rated as fast (but very brittle), then GP4ks and now the II’s.
I have 5k’s waiting to mount up once the current dancing shoes wear out.
All in 23’s.

So, other than that first response, none of my answers technically match the poll.

I replied 100, because I’m certainly not at “90 or less”.

I still have somewhat traditional narrow R rim, but a HED Jet C2 (and the road/training equivalent) up F.


float , hammer , and jog

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Re: Tire Pressure Poll [DFW_Tri] [ In reply to ]
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DFW_Tri wrote:
Ingles, por favor.

The ideal tire pressure will vary a lot depending on the road surface... among other things.

https://blog.silca.cc/...stance-and-impedance
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Re: Tire Pressure Poll [RowToTri] [ In reply to ]
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RowToTri wrote:
Is there a better source that I am missing?


You aren't considering road quality. The Silca study is best for that. And besides rider+bike weight, the tire design (not size) also influences ideal pressure.

And the chart you are referencing from Flo via Tom... I think originated from Michelin. At least it looks like one of theirs.
Last edited by: rruff: Aug 28, 19 21:04
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Re: Tire Pressure Poll [Slowman] [ In reply to ]
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"i think josh and tom a. and some of the other guys posting here have made an impact on you all. "

That I can agree with. I know they did for me, indeed.
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Re: Tire Pressure Poll [gary p] [ In reply to ]
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Thanks.
(I'd not spotted the rim width or all up weight was for the graph).

Interestingly, I'm heavier, on slightly narrower rims and now with 23mm GP5000s (rims narow and limited clearance on my bikes). I usually go about 100psi rear and 90 front. A few psi lower when wet.
So on the 'low' but 'safe' side if trying to extrapolate.

I'd bebattered to death on a long ride where folks are talking of 120+psi.
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Re: Tire Pressure Poll [smccauley49] [ In reply to ]
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smccauley49 wrote:
130 lbs
TT bike: 700 x 25 @ 80psi
Road bike: 700 x 28 @ 70 psi
Gravel: 700 x 32 @ 60 psi

Ouch, at your weight you would probably have a much better ride on gravel at around 35 to 40 psi. Ive got 20 pounds on you and that is what i ride. 60 psi is for when those rides when the tires don't go off pavement.
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Re: Tire Pressure Poll [RowToTri] [ In reply to ]
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Thanks for organizing these here. But, these charts are giving me a headache. Just when I was convinced lower is better, several of these suggest a much higher PSI than say the HED model (I typically run slightly higher than the HED model but much lower than the other ones)
Last edited by: DFW_Tri: Aug 29, 19 5:31
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Re: Tire Pressure Poll [plant_based] [ In reply to ]
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plant_based wrote:
But, I read that rolling resistance was lower on these at 120psi.

It is...on a glassy smooth testing roller or perfect surface velodrome. Even what you would consider a very good road surface is significantly rougher than that though.
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Re: Tire Pressure Poll [Bioteknik] [ In reply to ]
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Interesting, I'll give it a shot and see how it feels.

Thanks for the suggestion!
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Re: Tire Pressure Poll [smccauley49] [ In reply to ]
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smccauley49 wrote:
Interesting, I'll give it a shot and see how it feels.

Thanks for the suggestion!

Of course, I forgot to mention that tubeless or not makes a difference, as you don't want to pinch flat, but ride as low as you can without. Funny that in fall/winter/spring the gravel roads here are in better condition usually since there's enough rain to keep the braking bumps down, in summer those roads get considerably rougher.
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Re: Tire Pressure Poll [rruff] [ In reply to ]
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rruff wrote:
RowToTri wrote:
Is there a better source that I am missing?


You aren't considering road quality. The Silca study is best for that. And besides rider+bike weight, the tire design (not size) also influences ideal pressure.

And the chart you are referencing from Flo via Tom... I think originated from Michelin. At least it looks like one of theirs.

I am considering road quality, and bike weight. I've seen no data that would allow me to adjust pressure based on tire design (what like open the vs molded?) The silca road surface study does not include multiple rider weights and multiple tire widths so you kinda have to start at where you should be on smooth asphalt from other sources and use their road surface data to influence how much lower you might need to go from there.

-------------
Ed O'Malley
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Re: Tire Pressure Poll [Bioteknik] [ In reply to ]
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Yeah I run with tubes still so I'll probably start at 50 and drop down from there to see how it feels.

I'm familiar with that phenomenon all too well since I live on a gravel road. It's the worst when they resurface or grade it and bring all the loose stones up to the top!
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Re: Tire Pressure Poll [realbdeal] [ In reply to ]
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realbdeal wrote:
Mario S wrote:
realbdeal wrote:


Realistically the only difference between me and Mario S is a willingness to trust the science. And youth. And speed. And good looks.


That's nice. 👍

Amazing insite to someone you lnow the square root of Jack about.

Classy

Nice work editing out my pink? You're right though, the only statement I know is correct is the first. The rest was a pretty obvious joke. I have literally zero problems with people doing suboptimal things speed wise. I do have problems with people straight up disputing hard science AND acting like everyone who adheres to said science is an idiot.

Amen.

Mario can do whatever he wants, but posting incorrect information that is not factual or science based is a disservice to everyone. He's been trolling on multiple things lately. Glad you called him on it.
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Re: Tire Pressure Poll [RowToTri] [ In reply to ]
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23 mm Grand Prix 4000 (maybe 2,000km on them) On HED3 wheels ....forgot that part)
170 lbs race weight
Cervelo P3c
Kona ('fing hot)
Sea level

I am guessing (that means no actual knowledge) that Kona is pretty smooth (judging by YouTube) the wheels have no flex that a spoke'd wheel might (no one seems to talk about that), and the frame has some absorption in it (I might be wrong there) and the tires seem to be slightly wider than advertised (and if I buy new ones for one race, the wife will have something to say). Sea level...duh. :0)

85 front ?
90 rear ?

Opinion anyone?
Last edited by: michael Hatch: Aug 29, 19 7:26
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Re: Tire Pressure Poll [michael Hatch] [ In reply to ]
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What wheels are you using? Or better yet, what do your tires actually measure on your wheels?
Tires with visible wear down the center line are significantly less aero than new tires. They can have slightly lower Crr though.

-------------
Ed O'Malley
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Re: Tire Pressure Poll [RowToTri] [ In reply to ]
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Toying with using my beloved Hed3's front and back
Tires are as smooth as a baby's .....
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Re: Tire Pressure Poll [rruff] [ In reply to ]
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Ok, help me understand the charts. I didn’t need an article to understand that rougher roads slow us down. But, I can’t figure out from those charts what is the ideal PSI for each road surface. I think we can all fairly safely ignore the roughest surface. We might encounter that briefly on a ride but that ground up stuff is really only found when a road is under construction. So for asphalt (or smoothish roads), we should do what? For , chip seal, we should do what?
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Re: Tire Pressure Poll [DFW_Tri] [ In reply to ]
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DFW_Tri wrote:
Ok, help me understand the charts. I didn’t need an article to understand that rougher roads slow us down. But, I can’t figure out from those charts what is the ideal PSI for each road surface. I think we can all fairly safely ignore the roughest surface. We might encounter that briefly on a ride but that ground up stuff is really only found when a road is under construction. So for asphalt (or smoothish roads), we should do what? For , chip seal, we should do what?
There is no one size fits all here, but let's say for the sake of explanation that:

-You are the exact weight of the rider in testing (I think someone said that was 190lbs, or maybe that was rider+bike?)
-You know the entire course is the exact same pavement conditions as tested
-You are running the exact same tires and tubes

Now of course this is pretty much impossible, but if this was true you would want to use the pressure at the bottom vertex of the graph. So for brand new asphalt, 110psi; coarse, 100psi.
The reality is that you will never know the exact asphalt conditions and if you're running 10 psi too high you are going to lose way more than if you run 10psi too low. This is shown by the slope of the curve on either side of this break point. So in reality, assuming a mix between the brand new and coarse asphalt, you want to always be on the low pressure side of the break point. So maybe 90psi. Now this is for a heavier rider and there is very little risk to running it even lower, with the added benefit of comfort, so maybe scoot left another 5-10psi. There really are too many variables to base all your decisions off one graph but the biggest takeaway is to go less than what would be "ideal" for those conditions, because as soon as those conditions become worse than what you thought they were, you're losing out big time.

Benjamin Deal - Rookie Pro - Instagram - TriRig
Deals on Wheels - Race reports, pictures, sponsors, and more!
Most recent blog post: Takeaways from spectating Kona 2019
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Re: Tire Pressure Poll [RowToTri] [ In reply to ]
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RowToTri wrote:
I've seen no data that would allow me to adjust pressure based on tire design (what like open the vs molded?)

I think it was Velonews who published some data on this several years ago. The take-away is that the most supple tires will have less of a penalty at too-low PSI than the less supple ones, and I think the break point was higher as well. In other words the best tires will have a broader range where they perform close to optimal, so you can choose pressure for comfort or pinch resistance with little penalty.
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Re: Tire Pressure Poll [realbdeal] [ In reply to ]
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Makes sense. I realize it’s a different wheel but those PSI numbers are MUCH higher than, for example, what HED would suggest. That is what I am trying to sort out. I’m a heavier rider (195ish) so I will always be on higher side but even splitting the difference between smooth asphalt and chip deal, 105 PSI seems way to high to me
Last edited by: DFW_Tri: Aug 29, 19 8:38
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Re: Tire Pressure Poll [DFW_Tri] [ In reply to ]
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But that's the thing is that you don't want to split the difference. You want to always be under the optimal for the worst road conditions. Because anytime you're riding a pressure too high you lose a lot. And too low you barely lose anything. So take the worst road conditions you'll be riding for that course and go under optimal for that.

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Re: Tire Pressure Poll [DFW_Tri] [ In reply to ]
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DFW_Tri wrote:
Ok, help me understand the charts. I didn’t need an article to understand that rougher roads slow us down. But, I can’t figure out from those charts what is the ideal PSI for each road surface. I think we can all fairly safely ignore the roughest surface. We might encounter that briefly on a ride but that ground up stuff is really only found when a road is under construction. So for asphalt (or smoothish roads), we should do what? For , chip seal, we should do what?

The low point of the graph is the minimum Crr. Err on low side and adjust for your weight, the tires you use, and extrapolate for different road quality... easy ;)

Some chipseal is as rough as that machined concrete and some is quite smooth. If the surface is rough then run about as low as you can go and still avoid pinch flats or rim damage. If you can avoid potholes and gravel, then that can be quite low (I've had 23s as low as 70 psi in a TT, at 195lbs total weight). If the road is really nice (and especially if the white line is good to use), I'll go up to 110psi with the same tires.

I think there are a lot of people in this thread worrying about this a lot more than I do.
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Re: Tire Pressure Poll [plant_based] [ In reply to ]
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plant_based wrote:
https://www.bicyclerollingresistance.com/...grand-prix-5000-2018

Rolling resistance is lower on GP4000IIs and GP5000 at 120psi

I can honestly say tire pressure and rolling resistance is something I have never cared enough to research. This is mostly due to that I'm not exactly "aero" at 185 lbs.
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Re: Tire Pressure Poll [Jelana] [ In reply to ]
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Jelana wrote:
This. I used to run about 110 on 25mm Conti 4000s (tubes). Same tires/size, now I generally race and train at 90psi, and I'm significantly faster. For reference, my weight generally falls from low 150s (race weight) to up to 160 (post A-race sloth period weight). Added bonus is I don't have to worry about my tires exploding on a hot day.

OK, but in all honesty, aren't you significantly faster b/c you lost weight and also changed your training focus?

I'm all for the idea I too can be much faster by simply lowering my tire pressure. However, significantly? Really, based on tire pressure alone? I tried testing various pressures on as consistent a course as I could find, and I'm still skeptical.

To breathe, to feel, to know I'm alive.
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Re: Tire Pressure Poll [Tsunami] [ In reply to ]
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I bumped down the tire pressure last year, after I lost the weight and had some really strong bike legs at Maine 70.3 and IMAC in 2017. Honestly, with the exception of one or two particularly nasty interval sessions leading into Tallinn, I think my bike training this year hasn't been really much more intense than the past two years, particularly in 2017 when I was working to hold the same power levels while losing the weight. I've pushed the run a lot harder in the past year and a half, and that extra fitness could be playing in. I'm not sure how it all breaks down, but I did notice the bike both moving faster and being more comfortable to ride when I brought the tire pressure down. It is always difficult without a personal wind tunnel to figure out which adjustments are leading to the gains. I mean, maybe it's not tire pressure, weight loss, harder training or any of that, but that I got sick of Eric's withering looks at my frame bottle cages and removed them [for other STers playing along here, Tsunami and I are on the same team, and Eric is our aero enforcement officer].
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Re: Tire Pressure Poll [turdburgler] [ In reply to ]
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turdburgler wrote:

Mario can do whatever he wants, but posting incorrect information that is not factual or science based is a disservice to everyone. He's been trolling on multiple things lately. Glad you called him on it.

You been on the night nurse Turdy?

Not sure where iv posted incorrect info.

There's more to equipment choice than a wee colour graph that wows pre pubescent teens. It's nothing more complex than that.
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Re: Tire Pressure Poll [Slowman] [ In reply to ]
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Dan, I recently did a big Grand Fondo with some of my former bike racer friends, a couple of whom have TdF experience, and a discussion broke out over tire pressure. They just laughed and said in the real world this sub 100 psi is nuts. They threw out names of guys then and now and said they all ride 110 - 120 (on 23s), although a couple have gone to 25s with 105 ish pressure. So, are they old school and stubborn, or in the "real world" are they right?

David
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Last edited by: david: Aug 29, 19 14:23
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Re: Tire Pressure Poll [david] [ In reply to ]
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Pros used to ride 53-42 with a straight block 11-21 for mountain stages as well. Doesn't mean it was right for the other 99% of the world.

***
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Re: Tire Pressure Poll [M----n] [ In reply to ]
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M----n wrote:
Pros used to ride 53-42 with a straight block 11-21 for mountain stages as well. Doesn't mean it was right for the other 99% of the world.
(Or even right for the pros.)
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Re: Tire Pressure Poll [david] [ In reply to ]
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david wrote:
Dan, I recently did a big Grand Fondo with some of my former bike racer friends, a couple of whom have TdF experience, and a discussion broke out over tire pressure. They just laughed and said in the real world this sub 100 psi is nuts. They threw out names of guys then and now and said they all ride 110 - 120 (on 23s), although a couple have gone to 25s with 105 ish pressure. So, are they old school and stubborn, or in the "real world" are they right?

TDF will mean tubulars, not clinchers. Thus, smaller volume, and it doesn't change no matter what your rim size is. My experience with tubulars ended 20ish years ago, we started making wider clincher rims 12 years ago. I won't be wading any further into the weeds on particular point.

Andy Tetmeyer (I work at HED)

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Re: Tire Pressure Poll [realbdeal] [ In reply to ]
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21.5 rims - 25mm tires
~80 front
~85 rear

195 lbs

Ask me how much I love my Kiwami LD Aero Trisuit
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Re: Tire Pressure Poll [plant_based] [ In reply to ]
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plant_based wrote:
mjbruiser wrote:
Train on gator skins. Race on GP 4000's. 120 PSI for both regardless of road conditions.


I ride on these types of tires and put 120psi in them. Maybe I'm doing it wrong - idk. But, I read that rolling resistance was lower on these at 120psi.

Training on Gatorskin is good. That tire is pretty durable and you have less chance getting a flat during long ride.
If you switch to race wheels with race tires, you will feel lighter and faster with less effort.
I know a couple of friends running Gatorskins for their training.
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Re: Tire Pressure Poll [andy tetmeyer] [ In reply to ]
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andy tetmeyer wrote:
david wrote:
Dan, I recently did a big Grand Fondo with some of my former bike racer friends, a couple of whom have TdF experience, and a discussion broke out over tire pressure. They just laughed and said in the real world this sub 100 psi is nuts. They threw out names of guys then and now and said they all ride 110 - 120 (on 23s), although a couple have gone to 25s with 105 ish pressure. So, are they old school and stubborn, or in the "real world" are they right?


TDF will mean tubulars, not clinchers. Thus, smaller volume, and it doesn't change no matter what your rim size is. My experience with tubulars ended 20ish years ago, we started making wider clincher rims 12 years ago. I won't be wading any further into the weeds on particular point.

I have tubulars and put 120 psi and I'm 130lb. I tried 80, 85, 90, 100 and all feel sluggish and actually my bike time was slower for 60 miles ride when I put 90.
Idk, but 120 psi feels fantastic to me.
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Re: Tire Pressure Poll [s13tx] [ In reply to ]
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Do you personally glue the tires to your rims?

Why don't you carry a spare tire?
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Re: Tire Pressure Poll [jimatbeyond] [ In reply to ]
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jimatbeyond wrote:
Do you personally glue the tires to your rims?

Why don't you carry a spare tire?

I haven't removed and mounted tubular tires before.
I just take them to my LBS and they take care of it for me and yes, they glue them.
I saw a couple of people carrying a spare tubular tire in their jersey pocket at bike rallies and I don't know how they replace it.
I need to watch some youtube videos and learn.
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Re: Tire Pressure Poll [s13tx] [ In reply to ]
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How much does your bike shop charge to glue tires?
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Re: Tire Pressure Poll [jimatbeyond] [ In reply to ]
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jimatbeyond wrote:
How much does your bike shop charge to glue tires?
They charge $25 per tire IIRC. I asked to put some sealant in there and they didn't charge for that. My mechanic is one of the best in town, so I feel more comfortable him working on it than myself.
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Re: Tire Pressure Poll [s13tx] [ In reply to ]
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How many coats of glue does he apply?

Does he apply it around the entire rim?
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Re: Tire Pressure Poll [natethomas] [ In reply to ]
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100 on my tri bike.

About 75 on the gravel bike.
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Re: Tire Pressure Poll [Slowman] [ In reply to ]
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It's important to note that WheelEnergy and BicycleRollingResistace (as well as all of the other Crr machines/methods I've ever seen) are designed to specifically isolate tire losses due to hysteresis, or what we refer to as 'casing losses' and are NOT designed to pick up on any of the impedance losses seen when riding on the road. This makes sense as when you are designing a tire, you are only worried about what you can control through tire design and manufacturing, and everything else is just complicating noise.

The impedance part of the equation comes from testing with actual high hysteresis/high damping masses (humans) sitting imperfectly on actual bicycles riding on various surfaces. The impedance losses are always there, but are continually rising as pressure increases.. at some point they overcome the casing losses of the tire, as the bulk of the Crr moves from losses due to casing to losses due to shaking the high hysteresis mass on top of the bicycle.

Personally I think we need to reframe this post and so many others.. without knowing the MEASURED tire width, rider weight, and road surface it is impossible to have an opinion here.. so if somebody says they ride 120psi, we need to know way more before we say that it too much or too little.

Lastly, we are ~90% done with our pressure algorithm based on fitting thousands of real world test data points and look forward to sharing once the calculator is ready for prime-time. I think for many, the amount of information required on the input side will be surprising, but that's a good thing.

Josh

http://www.SILCA.cc
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Re: Tire Pressure Poll [SBRmd] [ In reply to ]
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SBRmd wrote:
JMike wrote:
Why is tire pressure always addressed as 'run' or 'ran'?


Everyone here says they are “running” this or that for anything. Can’t stand that.

If it's something some people might consider outlandish you don't just "run" it. You "rock" it:

"I was rocking disk wheels front and back"

[A few years ago - but no longer]: "Rocking disk brakes."

"Rockin' the speedo!"


http://www.jt10000.com/
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Re: Tire Pressure Poll [joshatsilca] [ In reply to ]
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joshatsilca wrote:

Personally I think we need to reframe this post and so many others.. without knowing the MEASURED tire width, rider weight, and road surface it is impossible to have an opinion here.. so if somebody says they ride 120psi, we need to know way more before we say that it too much or too little.
Josh


Glad someone else is making sense in this thread.
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Re: Tire Pressure Poll [joshatsilca] [ In reply to ]
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joshatsilca wrote:
...without knowing the MEASURED tire width, rider weight, and road surface it is impossible to have an opinion here..

AMEN!

This is such a simple concept but so poorly understood by so many. The wide variety of rim widths around these days has definitely complicated the situation and made most tire pressure charts worthless, hence the need for MEASURED tire width rather than the tire width printed on the sidewall.

I know a woman who recently had a nice custom steel frame made for her. Her new wheels had 25mm tires mounted on wide rims with an internal width of 21.5 mm. She thought 110 psi was just what you used for all road tires, and the harsh ride was a byproduct of the steel frame. After I set her straight, suddenly her new bike got a much nicer ride!
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Re: Tire Pressure Poll [joshatsilca] [ In reply to ]
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joshatsilca wrote:
It's important to note that WheelEnergy and BicycleRollingResistace (as well as all of the other Crr machines/methods I've ever seen) are designed to specifically isolate tire losses due to hysteresis, or what we refer to as 'casing losses' and are NOT designed to pick up on any of the impedance losses seen when riding on the road. This makes sense as when you are designing a tire, you are only worried about what you can control through tire design and manufacturing, and everything else is just complicating noise.

The impedance part of the equation comes from testing with actual high hysteresis/high damping masses (humans) sitting imperfectly on actual bicycles riding on various surfaces. The impedance losses are always there, but are continually rising as pressure increases.. at some point they overcome the casing losses of the tire, as the bulk of the Crr moves from losses due to casing to losses due to shaking the high hysteresis mass on top of the bicycle.

Personally I think we need to reframe this post and so many others.. without knowing the MEASURED tire width, rider weight, and road surface it is impossible to have an opinion here.. so if somebody says they ride 120psi, we need to know way more before we say that it too much or too little.

Lastly, we are ~90% done with our pressure algorithm based on fitting thousands of real world test data points and look forward to sharing once the calculator is ready for prime-time. I think for many, the amount of information required on the input side will be surprising, but that's a good thing.

Josh


Josh thats awesome your are making a "pressure algorithm" ....... In the end I think I have this figured out better then most so will probably minimize the small gap I have on the masses, but will be very nice to have especially if switching btw different tires. Cant wait to see it when its done, thank you.

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Re: Tire Pressure Poll [tttiltheend] [ In reply to ]
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tttiltheend wrote:
The wide variety of rim widths around these days has definitely complicated the situation and made most tire pressure charts worthless

Rim profiles have never been constant, tire width labeling has never been consistent, and manufacturer tire pressure charts have always varied wildly in methodology and rarely been very useful.
Last edited by: HTupolev: Sep 24, 19 9:47
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Re: Tire Pressure Poll [joshatsilca] [ In reply to ]
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Running Vittoria Cora EVO CX in 700 X 23mm Tubular on old Zipp 404 rims. Weight is 155 lbs. I've been running 100 psi. Do you think I should drop the pressure down to 95 or 90 psi?
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Re: Tire Pressure Poll [Herbie Hancock] [ In reply to ]
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Herbie Hancock wrote:
Running Vittoria Cora EVO CX in 700 X 23mm Tubular on old Zipp 404 rims. Weight is 155 lbs. I've been running 100 psi. Do you think I should drop the pressure down to 95 or 90 psi?

Have you not grasped the point yet that the only person that can answer that question is you!!!

Only you know the roads you ride on, only you know the way you like to ride the bike, only you know the compromises you are willing to live with.

Listen less to the experts (no seriously that's a joke) on here and test and try things out for yourself on the courses that you ride.

I run anything from 7 psi to 120psi depending on lots of factors.

Go find out for yourself what's best for you.
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Re: Tire Pressure Poll [Mario S] [ In reply to ]
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Thanks Mario but no time for testing. I barely have enough time to train and drink beer. Will drop to 95 psi and see what happens.
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Re: Tire Pressure Poll [Herbie Hancock] [ In reply to ]
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Herbie Hancock wrote:
Thanks Mario but no time for testing. I barely have enough time to train and drink beer. Will drop to 95 psi and see what happens.

That's how you do it - small adjustments, see how it goes. I think the larger thing he was getting at is that - even if you provide an insane amount of detail to the forum about your exact setup, weight, picture of the surfaces you ride on, power meter data, etc... it's still going to be tough for us to give you a perfect answer.

The take-home from our many home page articles on this topic, along with the Tubeless Super Thread is that, when in doubt, err on the lower side with pressure. You're dropping by 5psi... that's a reasonable move. If you start striking the rim on the pavement a bunch and risking rim damage, that would tell you to raise the pressure back up. If it doesn't feel like anything changed, you might try dropping it a bit more. It's that simple. The only absolute here is that you shouldn't be running more than ~120psi under pretty much any circumstance.

I get a lot of questions about this and people want a perfect answer, but the reality is that you just have to try it for yourself. The only real way to know the exact perfect pressure for a specific piece of road is to get a power meter and do your own controlled testing at different pressures.

Greg Kopecky - Slowtwitch Tech Editor
Founder of Minimal Multisport Athlete website, blog, podcast, and Youtube channel: https://www.minimalmultisport.com/
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Re: Tire Pressure Poll [joshatsilca] [ In reply to ]
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After reading this thread I plan on switching from 120 psi on (both tires) to 95 on Front and 100 Rear for "new" (read wide) zipps.
My question is should I try these same pressures on my "older" (read narrower) Reynolds strike winter wheels. I weigh a whooping 195lbs (read I need to put the cookie down, lol) ty
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Re: Tire Pressure Poll [bikeenvy] [ In reply to ]
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How wide are your tires?
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Re: Tire Pressure Poll [jimatbeyond] [ In reply to ]
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25's
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Re: Tire Pressure Poll [bikeenvy] [ In reply to ]
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What width do they measure when mounted on your wheels?
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Re: Tire Pressure Poll [bikeenvy] [ In reply to ]
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bikeenvy wrote:
Reynolds strike winter wheels.

You have to laugh!
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Re: Tire Pressure Poll [RowToTri] [ In reply to ]
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RowToTri wrote:
Interesting - they seem to be in the lower pressure camp. I posted this in another thread but maybe I should have posted it here:

Some of the information out there on tire pressures seems to be conflicting.

Here is Roval's recommendation (I run a Roval CLX 64 front wheel)


Here is HED's recommendation (I run a Jet Disc Plus on the rear)


My 23c GP5000 tire measure 26mm at 85 psi on my front wheel. Roval does not say if it's chart is for measured or labeled tire widths, but it would recommend >107psi if labeled, 89 if measured. HED's chart is for labeled width so they recommend 72 psi. Quite a huge difference! What is one to do? They cannot both be right.

On the rear, I've been running a 23C GPTT which actually measures 27.75mm on my HED Jet Disc Plus! I'm re-thinking that tire right now, given the 25mm brake track on that wheel, but the aerocoach testing puts it ahead of the GP5000 on their wheel - need to get the width of that wheel. At least in the back it's shrouded.



From Silca's website, I cannot find a chart with enough data to really select a pressure given tire width and rider weight, but there is this, which seems to suggest even higher pressures than roval, but we do not know rider weight:


Here's a chart from Flo (They apparently got it from TomA) which I'm pretty certain refers to measured width and recommends about the same as roval, ~90.


My inclination is to go with the Flo(TomA)/Roval recommendations since they agree, and Tom does a solid job in this testing.

Is there a better source that I am missing?

My race wheels are Bontetrager Aeolus70's. Tires sit "wide" in there, so they look like they are 25's vs 23's. I am 145 lbs and go with 80-90 psi based on road surface. In training I have 28mm Vittoria Corsa CX and I go with 60-65psi. I may put 70psi if I am training in Tremblant where the road surface is near perfect
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Re: Tire Pressure Poll [devashish_paul] [ In reply to ]
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HED wheels have been winning world championships for decades so I give their charts the nod.

I'm ~150 lb. and run a FLO 60 front, GP4k II 23c, latex at 75psi and a HED Jet+ Black Disc rear, GP4k II 23c, latex at 75psi.

Looking forward to Silca's calculator! I assume I'm right in the ballpark after listening to his podcasts.

-------------------
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Last edited by: Timtek: Sep 29, 19 7:17
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