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23 v. 25 vs. 28 mm tire width?

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23 v. 25 vs. 28 mm tire width?

Old 05-19-21, 12:20 PM
  #76  
vane171
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Originally Posted by PeteHski View Post
I think this assumed trade-off between tyre width and speed is rapidly becoming out of date. 23s are already history. Pro level race bikes are now being optimised around 25+ width tyres.
Could that be because race courses generally include many poorer road surfaces on which I wouldn't do my usual rides if I had a choice? For example, in the area where I ride bike, roads between small towns and villages where I can plot rides of various length, there is one road section in an outlaying area where gravel protrudes through old asphalt surface which makes the bike vibrate with high frequency that is extremely unpleasant.

It even makes me worry about the cyclo computer to the extent that I remove it from its holder and stash it in my pocket (can't read its display anyway due to vibration). Also one starts to appreciate bar padding tape. If I had to ride on such roads more frequently, I'd certainly look at bigger tire sizes that can be inflated to lower pressure. As it is, I mostly avoid routing my rides to take me on that road.

Pro racing courses are also quite long, which together with the road surface that leaves lots to be desired, leads to the bigger tire size choice. I guess also that today's pros put on more race kms per season than used to be the case some decades ago. Apart from the move to wider tires, you also get these bike frames with built in shock absorbing features, none of which existed some 30+ yrs ago, give or take some decades since I am no historian regarding that.

Just noticed your spelling 'tyres'

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Old 05-19-21, 12:28 PM
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Originally Posted by vane171 View Post
Could that be because race courses generally include many poorer road surfaces on which I wouldn't do my usual rides if I had a choice?
No. It's because they've found that 25s are actually faster.
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Old 05-19-21, 12:52 PM
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Originally Posted by vane171 View Post
Could that be because race courses generally include many poorer road surfaces on which I wouldn't do my usual rides if I had a choice? For example, in the area where I ride bike, roads between small towns and villages where I can plot rides of various length, there is one road section in an outlaying area where gravel protrudes through old asphalt surface which makes the bike vibrate with high frequency that is extremely unpleasant.

It even makes me worry about the cyclo computer to the extent that I remove it from its holder and stash it in my pocket (can't read its display anyway due to vibration). Also one starts to appreciate bar padding tape. If I had to ride on such roads more frequently, I'd certainly look at bigger tire sizes that can be inflated to lower pressure. As it is, I mostly avoid routing my rides to take me on that road.

Pro racing courses are also quite long, which together with the road surface that leaves lots to be desired, leads to the bigger tire size choice. I guess also that today's pros put on more race kms per season than used to be the case some decades ago. Apart from the move to wider tires, you also get these bike frames with built in shock absorbing features, none of which existed some 30+ yrs ago, give or take some decades since I am no historian regarding that.

Just noticed your spelling 'tyres'
No, its just engineering evolution. Tyres = UK spelling.
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Old 05-19-21, 02:26 PM
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Originally Posted by Eric F View Post
No. It's because they've found that 25s are actually faster.
To be fair, I think his point is that 23s are faster, but pros are switching to 25s because those are faster in the real world. I can't disagree with the second part. 🙂
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Old 05-19-21, 02:32 PM
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I don't think I've ever actually ridden 25s. I used to ride a CX bike with 28s and 32s. Bought a road racing bike with 23s and no clearance for anything wider. My next several bikes were the same basic thing. Funny how we come full circle, I'm riding 28s now on Enve SES rims that balloon them out to 33 mm. Those Enves with 28s are faster than the box section rims I used to use with 23s. Both of those experiences on Cervelos. I'm not saying 28s are always faster than 23s, I'm saying 23s aren't automatically faster than bigger tires.
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Old 05-19-21, 02:35 PM
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Originally Posted by Seattle Forrest View Post
To be fair, I think his point is that 23s are faster, but pros are switching to 25s because those are faster in the real world. I can't disagree with the second part. 🙂
The real world is a good place for them to be faster. After all, that's where the pros race.
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Old 05-19-21, 02:48 PM
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Originally Posted by Redbullet View Post
Ignoring that amateurs never run Paris Roubaix, never run 150-200 km races
You greatly underestimate the ability of serious, well-trained amateurs and the events they challenge themselves with.
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Old 05-19-21, 03:12 PM
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Originally Posted by Eric F View Post
The real world is a good place for them to be faster. After all, that's where the pros race.
I'm working on this new racing venue where you show up with your FTP number and whoever has the best one wins. You don't even need a bike!
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Old 05-19-21, 03:13 PM
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Originally Posted by Seattle Forrest View Post
I'm working on this new racing venue where you show up with your FTP number and whoever has the best one wins. You don't even need a bike!
You laugh, but there was a guy here who used to think you should qualify for real world races based on Strava segments.
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Old 05-19-21, 03:14 PM
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Originally Posted by Seattle Forrest View Post
To be fair, I think his point is that 23s are faster, but pros are switching to 25s because those are faster in the real world. I can't disagree with the second part. 🙂
The pros going for the fastest possible setup ride the narrowest possible tire at the highest possible pressure below the impedance breakpoint that avoids the possibility of pinch flats.
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Old 05-19-21, 03:14 PM
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Originally Posted by Seattle Forrest View Post
I'm working on this new racing venue where you show up with your FTP number and whoever has the best one wins. You don't even need a bike!
Zwift is pretty close to that already - LOL.
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Old 05-19-21, 04:33 PM
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Originally Posted by asgelle View Post
The pros going for the fastest possible setup ride the narrowest possible tire at the highest possible pressure below the impedance breakpoint that avoids the possibility of pinch flats.
What's an impedance breakpoint?

(Never heard that term in relation to bicycle tires.)
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Old 05-19-21, 04:35 PM
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Originally Posted by terrymorse View Post
What's an impedance breakpoint?

(Never heard that term in relation to bicycle tires.)
https://blog.silca.cc/part-4b-rollin...-and-impedance
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Old 05-19-21, 04:45 PM
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Originally Posted by asgelle View Post
The pros going for the fastest possible setup ride the narrowest possible tire at the highest possible pressure below the impedance breakpoint that avoids the possibility of pinch flats.
Sometimes they use a narrower front tire because it's more affected by air resistance:

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Old 05-19-21, 04:50 PM
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Interesting, thanks.

So impedance is affected by the surface roughness. The rougher the surface, the higher the impedance. Roughly speaking.
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