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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

Gone with the wind

Instagram: palmtreestriathlon
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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 > YVR
2024 Races: Taupo
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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 - Professional - Instagram - TriRig - Lodi Cyclery
Deals on Wheels - Results, schedule, videos, sponsors
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 - Professional - Instagram - TriRig - Lodi Cyclery
Deals on Wheels - Results, schedule, videos, sponsors
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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+

Washed up footy player turned Triathlete.
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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. đź‘Ť

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. đź‘Ť

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 - Professional - Instagram - TriRig - Lodi Cyclery
Deals on Wheels - Results, schedule, videos, sponsors
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
Founder of VeloVetta Cycling Shoes
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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 - Professional - Instagram - TriRig - Lodi Cyclery
Deals on Wheels - Results, schedule, videos, sponsors
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