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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. 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.

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

Benjamin Deal - Professional - Instagram - TriRig - Lodi Cyclery
Deals on Wheels - Results, schedule, videos, sponsors
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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
* Ironman for Life! (Blog) * IM Everyday Hero Video * Daggett Shuler Law *
Disclaimer: I have personal and professional relationships with many athletes, vendors, and organizations in the triathlon world.
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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