# If 25c tires are faster than 23c, then why are 25c race tires so hard to find?



## f3rg (May 11, 2008)

Going through manufacturers' tire lists, you can find almost anything in a 23c, but when it comes to 25c, good luck, unless you're looking for a heavier commuter tire. I think Kenda only offers one model, Conti obviously has a small handful, and Panaracer apparently doesn't offer them in the U.S. (at least, they aren't easy to find). Maxxis seems to only offer one type, and Michelin only offers a couple.

What's the deal?


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## PlatyPius (Feb 1, 2009)

Distributors/retailers only stock what customers will buy.

Customers (as a whole) are stupid.

Ergo, 700x25 is somewhat difficult to find.

(Not at my shop, of course)


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## dot (Mar 4, 2004)

Conti GP4000 700x25. Who needs anything else? The thing is GP4000 700x23 actually measures 24mm and 700x25 is 25mm and a couple of mms taller. Can't feel any difference.


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## tihsepa (Nov 27, 2008)

I run GP 4000 4 Seasons in a 25. They are nice.


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## bikerjulio (Jan 19, 2010)

Michelin Optimum


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## rubbersoul (Mar 1, 2010)

How do you know 25 is faster than 23?


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## Sisophous (Jun 7, 2010)

rubbersoul said:


> How do you know 25 is faster than 23?


I do not know this but I came across a discussion board where people compare the sizes. It is an interesting read. From what I got, the 25s are a slightly better tire for larger size people and are less inclined to cause pinch flats while giving a more comfortable ride. It makes sense because I only got a couple of flats over years of riding when I had larger size tires (I believe 25s) on my last bike compared to my 23s now where I’ve had 4 flats since last June.

http://www.beginnertriathlete.com/discussion/forums/thread-view.asp?tid=109566&posts=9&start=1


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## waldo425 (Sep 22, 2008)

I have some really nice 25c Specialized Roubaix S-Works open tubular tires.


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## Salsa_Lover (Jul 6, 2008)

they are not.

25c tyres are for old clydes on their "comfort" bikes.

NWWT anyway


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## JustTooBig (Aug 11, 2005)

Salsa_Lover said:


> they are not.
> 
> 25c tyres are for old clydes on their "comfort" bikes.
> 
> NWWT anyway


if we could all raise the level of badass-itude to the legendary stratospheric levels that Salsa Boy does, there would be no need for any tire bigger than 700x19. 

Alas, 'taint the case.


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## LMWEL (Jan 5, 2010)

I agree with you, they are hard to find . You should try finding them in colors . Here's a link- http://www.biketiresdirect.com/sear...=true&clinchwire=true&tubclinch=true&ust=true


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## tihsepa (Nov 27, 2008)

JustTooBig said:


> if we could all raise the level of badass-itude to the legendary stratospheric levels that Salsa Boy does, there would be no need for any tire bigger than 700x19.
> 
> Alas, 'taint the case.


Yah, but he impresses himself.:thumbsup:


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## MikeBiker (Mar 9, 2003)

waldo425 said:


> I have some really nice 25c Specialized Roubaix S-Works open tubular tires.


If the tubes are open, won't the air fall out?


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## SystemShock (Jun 14, 2008)

Salsa_Lover said:


> they are not.
> 
> 25c tyres are for old clydes on their "comfort" bikes.
> 
> NWWT anyway



Which is why Salsa rides on strips of iron like the riders of yore, aka 'Let's party like it's 1869'. 

Anything less would be insufficiently 'hard man' for him. :thumbsup: 











...*"HTFU!!!"*
.


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## Serotta 63 (Nov 2, 2009)

dot said:


> Conti GP4000 700x25. Who needs anything else? The thing is GP4000 700x23 actually measures 24mm and 700x25 is 25mm and a couple of mms taller. Can't feel any difference.


+4 since I have 4 of them... great tire.


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## cxwrench (Nov 9, 2004)

PlatyPius said:


> Distributors/retailers only stock what customers will buy.
> 
> Customers (as a whole) are stupid.
> 
> ...


^^^this...^^^
and the fact that 23's are lighter than 25's, and refer back to 'customers are stupid'. people read the weight, and of course think that lighter is better. whether or not they would still roll faster on the larger tire at lower pressure. :mad2:


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## Salsa_Lover (Jul 6, 2008)

no need to get offended

7 years and 7 kilos ahead I will be also in the need of 25c tyres ( or larger )


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## Peanya (Jun 12, 2008)

700x25 costs a little more to make, yet sell for the same price. Most pros who weigh in the low 100's use them. Choice creates confusion to a customer. Most people believe a smaller contact patch will yield a lower rolling resistance (which is true, to a degree). Those are some of the reasons.
As for the argument to which is faster, yes the 25's will have a slightly lower rolling resistance, but how much time would be saved over 100 miles? Maybe a couple of seconds? The more comfortable ride will leave you less fatigued, so there's where the true speed benefit will come from.


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## asgelle (Apr 21, 2003)

cxwrench said:


> ^^^this...^^^
> and the fact that 23's are lighter than 25's, and refer back to 'customers are stupid'. people read the weight, and of course think that lighter is better. whether or not they would still roll faster on the larger tire at lower pressure. :mad2:


Aren't we forgetting something here? Or do your customers ride in a vacuum?


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## Sisophous (Jun 7, 2010)

Salsa_Lover said:


> 25c tyres are for old clydes on their "comfort" bikes.
> 
> NWWT anyway


I like a poster who has spunk and speaks his mind. 

I am considering getting the 25c just to experiment with it. Speed isn’t such a big deal, you can only ride so fast where I go without putting yourself in danger. On my 30 speed Trek Madone, I only use gears 11-20 for all terrain, including hills.

What is the point of gears 21-30 unless you want to go over 30 mph.


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## TomH (Oct 6, 2008)

asgelle said:


> Aren't we forgetting something here?


Considering we're talking about tires.. nope! 

All though Ive never had any trouble finding 25's. They're everywhere if you're willing to shop in more than one place. I could have a lifetime supply of different 25c's ordered up by the end of the day.


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## asgelle (Apr 21, 2003)

TomH said:


> Considering we're talking about tires.. nope!


Given the work that's been done recently on optimizing rim shapes for low drag specific to a particular tire width, I'm not sure you've considered all the aspects of the problem in your answer. It goes well beyond frontal area of the tire.


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## Mr. Versatile (Nov 24, 2005)

The reason 25s are less popular is twofold:
1. Tradition
2. Misinformation.


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## Ventruck (Mar 9, 2009)

SystemShock said:


> Which is why Salsa rides on strips of iron like the riders of yore, aka 'Let's party like it's 1869'.
> 
> Anything less would be insufficiently 'hard man' for him. :thumbsup:
> 
> ...


Saddle's too low, handlebars too high, headtube is too tall, top tube too short, not enough gear inches.

As for the general debate. I'm running 23-front/25-rear. Honestly, through my trial and error I can't tell differences as maybe I am still that "young and light" (21yo, ~140lbs). I'm just assuming that with the supposed longer contact patch of the 23, it's more "assertive" in cornering. I wasn't as comfortable with the last 25 I ran up front, but then again that could be due to things beyond the size. Meh.


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## Fredrico (Jun 15, 2002)

One researcher, I can't remember his name, explained why 25Cs have slightly less rolling resistance than 23Cs. 25Cs have a wider, shorter, rounder contact patch. That has less rolling resistance than narrower tires which deflect more, flatten, as they roll. A long contact patch flattens the tire more than a wider, rounder one, load and air pressure being the same. That's also, IME, the reason sharp objects cut them and get embedded more often. The "flatter" tire is on the ground longer than a 25C (or tubular, also known for it's superior flat resistance) so the sharp object has more time to cut into the rubber. :biggrin5:


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## WA/SScrossracer (Oct 4, 2010)

I found some Schwalbe Duronos in a 25c size that I now have on my cross check commuter, after I ripped a 23c Pro race Michellin -may have been slightly underinflated, but I'm sure at least at 90psi- hit a good sized bump in the paved bike trail with rack and panniers and had a pinch flat/w a small rip in the sidewall. So far the Schwalbe's are running good with the rack fenders/bags, running 110PSI(I'm about 170#)- could probably run them a little lower, maybe 90 perhaps. But they ride pretty nice and are pretty light about 250G - so 20-30g more then the pro race 2 tires.


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## Fredrico (Jun 15, 2002)

WA/SScrossracer said:


> I found some Schwalbe Duronos in a 25c size that I now have on my cross check commuter, after I ripped a 23c Pro race Michellin -may have been slightly underinflated, but I'm sure at least at 90psi- hit a good sized bump in the paved bike trail with rack and panniers and had a pinch flat/w a small rip in the sidewall. So far the Schwalbe's are running good with the rack fenders/bags, running 110PSI(I'm about 170#)- could probably run them a little lower, maybe 90 perhaps. But they ride pretty nice and are pretty light about 250G - so 20-30g more then the pro race 2 tires.


I ride a similar setup, rack and panniers, and have no trouble catching, er, drafting Pinarellos and Madones with *28C Gatorskins!* Last flat was two years ago on a shoulder that had just been filled with debris by a snow plow.


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## SystemShock (Jun 14, 2008)

Salsa_Lover said:


> no need to get offended
> 
> 7 years and 7 kilos ahead I will be also in the need of 25c tyres ( or larger )



^ *pssst* Fixie riders think yer soft 'cuz you use more than one gear. :wink5:

Anyways, for myself, from much past experience (and bear in mind my riding weight over the years has been in the 210-240 lb range):


*19/20c:* Absolutely AWFUL. Probably spent more time fixing flats than actually riding. Nil ride comfort too. 
*23c:* As above, but maybe 75% as bad. Frequent flats, and maybe a hint of a ghost of sliver of something that would begin to resemble ride comfort... though still quite crappy there. 
*25c:* These were fairly nice. Flats finally stopped being a major issue, and the ride quality was reasonably comfortable.
*26-29c:* Actually liked these best. Very few flats, rolled easily, and just so smooooooooth. And you can buy very high-quality and pretty durn light 28Cs these days (thank you thank you, Challenge and Grand Bois). :yesnod:
*32c & up*: IMO, no burning need to go to these unless your local roads look like Afghanistan and/or you weigh as much as an NFL lineman. But someone out there will have a different take, I'm sure. Some ppl really like the 'magic carpet ride' you get with high-quality tires this size and up... even though just the thought of running these gives ppl like Salsa a heart attack. :lol:​

Btw, doing the math/extrapolating out air volumes, if I were a middleweight (160-175 lbs), I'd probably like 25c best, and 23c would be decent-but-second-(or third?)-best. Hmm... 

In the end, tho', *ride what you like*. If you weigh 135 lbs soaking wet, or just simply have different preferences regarding ride quality and 'feel' (not to mention what your local roads are like), your needs are obviously going to be very different than mine. And I certainly don't believe my needs (or yours) represent those of everyone.

Run what you dig, and if the poseurs don't like it, well, whatever. Their approval/disapproval should never make or break your riding. 



/ ps– Want some high-quality 'beeg' tires? A good place to start: (btw, Challenge used to be Clement)

http://www.compasscycle.com/Tires.html
.


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## f3rg (May 11, 2008)

Salsa_Lover said:


> no need to get offended
> 
> 7 years and 7 kilos ahead I will be also in the need of 25c tyres ( or larger )


Meh, has nothing to do with weight or age. I'm 140lbs and can tell a big difference between 23c and 25c. Before moving up to 25c tires, I figured there was nothing an extra couple mm of rubber could do to help smooth out the ride, but when I finally did get some, I saw why so many people prefer them.


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## TomH (Oct 6, 2008)

asgelle said:


> Given the work that's been done recently on optimizing rim shapes for low drag specific to a particular tire width, I'm not sure you've considered all the aspects of the problem in your answer. It goes well beyond frontal area of the tire.


The difference between the most aero wheel and least aero wheel isnt very significant.. Its nearly splitting hairs even for racers. The difference between a more or less aero size on the same wheel is irrelevantly small.


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## Fredrico (Jun 15, 2002)

*Tha's certainly true.*



TomH said:


> The difference between the most aero wheel and least aero wheel isnt very significant.. Its nearly splitting hairs even for racers. The difference between a more or less aero size on the same wheel is irrelevantly small.


But in the context of speed, a slightly wider tire, having a rounder contact patch and therefore deforming less, has less rolling resistance and goes measurably faster than a skinnier tire with a longer, narrower contact patch, as I mention below. :biggrin5:


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## Sisophous (Jun 7, 2010)

f3rg said:


> I'm 140lbs and can tell a big difference between 23c and 25c.


This is good news to hear. I am definitely going to get new tires and replace my 23c. I was wondering if the 26c would even be better than the 25c? And would you compromise speed going to 26c instead of 25c?


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## Fredrico (Jun 15, 2002)

*No compromise.*



Sisophous said:


> This is good news to hear. I am definitely going to get new tires and replace my 23c. I was wondering if the 26c would even be better than the 25c? And would you compromise speed going to 26c instead of 25c?


26Cs are about as wide as tubulars, known for their low rolling resistance and wonderfully cushy ride. :thumbsup: They're perfect for urban riding, just like 28Cs. Unloaded, they just deform less and go faster! The slight weight handicap is easily overcome and only noticeable on hills.


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## asgelle (Apr 21, 2003)

TomH said:


> The difference between the most aero wheel and least aero wheel isnt very significant.. Its nearly splitting hairs even for racers. The difference between a more or less aero size on the same wheel is irrelevantly small.


FIrst of all I have no idea what significant means to you - minutes, seconds, thousandths of a second? What? The best aero wheels are 1-2 minutes faster than a standard one over 40 km. The best tire will be 10's of seconds faster than a poor one (aerodynamically) over the same distance.

Aero differences are small, rolling resistance differences are small, weight differences are small. The fastest tire will depend on the particular magnitudes of these small effects. No one can be ruled out without considering the specific values for the case in question.


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## 74extiger (Jan 29, 2011)

There is a bit of physics that enters into things. Because the weight is concentrated at the rim of the wheel, even small increases greatly retard acceleration. It is a rotating mass, which by definition is a flywheel.

I myself just switched to 25mm tires and I like the ride. I ride at a constant speed. But in races with lots of sprints, even a few grams feels like a ton. My old tires were the Continental Attack Force, which couples a 23mm rear with a 19 mm front, and boy, was that ever zippy. But I don't race.

Great to read all the comments here. I'm looking forward eagerly to no flats.


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## TomH (Oct 6, 2008)

Fredrico said:


> But in the context of speed, a slightly wider tire, having a rounder contact patch and therefore deforming less, has less rolling resistance and goes measurably faster than a skinnier tire with a longer, narrower contact patch, as I mention below. :biggrin5:


I definitely agree. I think its noticeable.. Less fatiguing as well (a combo of resistance vs softer ride.. probably comfort contributing more). 

The 25c's even feel faster.. you notice right away.


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## Mr Pink57 (Mar 30, 2011)

The Schwalbe Ultremo R.1 came in a 25c (I have a set). And I ams ure a lot of other Schwalbe tires come in a 25c I don't think you're looking hard enough.


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## benInMA (Jan 22, 2004)

To add more to the "25s aren't always better" stuff..

You might have to experiment with different rims and different 25c tires to find a combo you like as well.

If the rim isn't wide enough you can have quite a bit of a "flop" effect with a 25c as the tire is wider then the rim.. it can mess with the ride quality. For those rims the 23c will feel better...

There are a lot more "wide rim" options now then there used to be though.

Just cause the tire says it's 23c or 25c also doesn't make it so.. the manufacturers all seem to have different systems of measuring the tire!


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## Serotta 63 (Nov 2, 2009)

My 2 cents...

Let the weight of the Rider + Bike determine if you should even ride a 23. For me at total weight of 240lbs kinda makes 23s not a good choice.


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## wim (Feb 28, 2005)

Fredrico said:


> But in the context of speed, a slightly wider tire, having a rounder contact patch and therefore deforming less, has less rolling resistance and goes measurably faster than a skinnier tire with a longer, narrower contact patch, as I mention below. :biggrin5:


I guess that's why pros all ride the widest tire they can possibly fit into their frames. With glory and lots of money at stake, who would not want to claim the speed advantages of a 25 over a 23?


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## Hank Stamper (Sep 9, 2009)

wim said:


> I guess that's why pros all ride the widest tire they can possibly fit into their frames. With glory and lots of money at stake, who would not want to claim the speed advantages of a 25 over a 23?


Pro teams just don't know any better. If they spent less time doing scientific research and riding and more time goofing off on the internet they'd be as well informed as some of the people on this thread.


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## mtbbmet (Apr 2, 2005)

Mich Pro 3's are available in 25, so are ultremo's, Vittoria's, challenge, Conti and others.
Every study ever done says 25s have a lower rolling res than 23's. Not sure why this is still debated.


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## wim (Feb 28, 2005)

mtbbmet said:


> Every study ever done says 25s have a lower rolling res than 23's. Not sure why this is still debated.


Because this statement is only half-true. 25s have lower rolling resistance than 23s only at identical tire pressures. That qualification is crucial because no one runs 25s at the same pressure than they would run 23s. Therefore: at recommended tire pressures, 23s have less rolling resistance then 25s.

Of course, there's nothing that prevents you from running 25s at the same pressure than you would run 23s. But if you do, comfort would suffer. At identical pressures, the larger tire is harder and less forgiving. If you want the physics, look up how container wall tension is a product of pressure and volume ("boiler formula.") But you really don't have to—check and see how the load rating of tires go up with volume and recommeded pressure going down. I've got two tractor rear tires that are rock-hard at 17 psi.


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## thumbprinter (Jun 8, 2009)

i am one of those '135lb soaking wet' riders and i love my 32s. wouldn't trade em for anything. and i can probably keep up with you, especially on the hills (up or down).....


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## Slim Again Soon (Oct 25, 2005)

As someone noted earlier, tradition is one reason why 23s continue to be the tires most commonly found in shops and on the road.

Any time spent on this cycling forum, or any other, gives evidence of how people are nervous about breaking from tradition, and how many others are quick to condemn, mock, etc., such behavior.

That said ... 25s are superior tires for most riders.

Oddly enough, it is easier to find 28s (another great tire for general riding).


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## ZoSoSwiM (Mar 7, 2008)

I felt more comfortable when I switched from 23mm kenda tires to 25mm Conti GP4000's. I felt more comfortable and faster therefore I was faster

Recently picked up some Ultremo ZX 23mm tires.. see if they feel any faster. If they don't I'll go back to my koolaid.


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## SystemShock (Jun 14, 2008)

Hank Stamper said:


> Pro teams just don't know any better. If they spent less time doing scientific research and riding and more time goofing off on the internet they'd be as well informed as some of the people on this thread.


The 'pro rider' comparison isn't such a good one.

Most pros weigh like 130-160 lbs, quite often are on tubulars, and have team cars following them around with spare wheels.

Most recreational riders are significantly heavier than that, usually are on clinchers, and fix their own flats right there on the roadside.

So, should rec riders _*really*_ use the same tires as pro riders, or are they just victims of aspirational purchasing/marketing? :idea:


(btw and even so, you do see some pro teams running 27mm tubulars for events like Paris-Roubaix) 
.


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## SystemShock (Jun 14, 2008)

benInMA said:


> Just 'cause the tire says it's 23c or 25c also doesn't make it so.. the manufacturers all seem to have different systems of measuring the tire!


Very good point. There are a lot of 'faux' 23Cs and 25Cs out there, throwing comparisons out of whack.

You'd love to see one standardized way of measuring, but I guess the tire makers are in love with fudging the numbers for marketing's sake.

For example, if I'm a tire maker, my '23C' tire can be lighter than yours if it's REALLY a 22 or 21mm tire that I _say_ is 23C. rrr: 
.


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## herbn (Aug 22, 2009)

i accidentally bought a 25mm mich litheon,kind of liked it then bought the other one too,havn't looked back. i don't know about rolling faster, i was particularly active over the winter on my rollers with the headwind attachment, so the tires just seem to be getting faster and faster.There's a 20 gram weight penalty for the 2mm and about another 20 for them not being a prolevel tire. When i first switch i could feel a little bit more drift up front ,when cornering. I attributed it to a harder compound , but it seems to have gone away perhaps as the tread wore in.I've been inflating them every couple of days to 105psi. I was used to pro 3's


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## rubbersoul (Mar 1, 2010)

what about Conti 24c clinchers?? Booyah!


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## fontarin (Mar 28, 2009)

I will likely go back to 23c because the tire I like is only available in that. I'm riding 25 GP 4000 at the moment, but I prefer Vredestein Fortezza SEs (they're also cheaper than GP4000s).


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## atimido (Jun 17, 2009)

TomH said:


> I definitely agree. I think its noticeable.. Less fatiguing as well (a combo of resistance vs softer ride.. probably comfort contributing more).
> 
> The 25c's even feel faster.. you notice right away.


I personally think you are onto something here that a lot of the posters aren't realizing. I ride 700 x 23 tires, and someone who rides 700 x 25 tires isn't necessarily going to be faster than me simply because they ride a wider tire. In actuality, the individual is just not as likely to exert as much effort to make that tire roll at the same speed as if they were using 700 x 23 tires. Why people choose 700 x 23 over 700 x 25, who cares? Its personal choice, and to think otherwise is asinine. If you want to be a Fred and ride 700 x 25s with your panniers and your helmet mirror, so be it, just like if I want to ride 700 x 23 tires doesn't necessarily make me an idiot consumer. It’s what I like to ride, particularly when they are tubular... Thanks.


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## MerlinAma (Oct 11, 2005)

Isn't this a trade off issue?
Assume 25's roll better but 23's are lighter.
Will the weight savings offset the better rolling? That may depend on several issues like how flat is the terrain and how good are the roads. Then throw in your personal weight and how comfy you want to be.
I don't see it as a "black and white" answer. 
And also you have to throw in your own "ego" factor and bias, one way or the other! Ha!


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## ziscwg (Apr 19, 2010)

rubbersoul said:


> what about Conti 24c clinchers?? Booyah!



Hummm, the only 24c I know is the Vittoria Open Pave....

I have one and like it. I have it because that WAS the biggest tire I could fit. Now that I have a new fork, I will go 25 when it wears out. I do like it though, but it's hard to find in blk


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## asad137 (Jul 29, 2009)

wim said:


> Of course, there's nothing that prevents you from running 25s at the same pressure than you would run 23s. But if you do, comfort would suffer. At identical pressures, the larger tire is harder and less forgiving. If you want the physics, look up how container wall tension is a product of pressure and volume ("boiler formula.")


I don't think that's the only relevant physics. Sure, wall tension goes up but only linearly with the width of the tire. Volume, on the other hand, goes up as the square (assuming the overall tire diameter for a given wheel size stays more-or-less constant). For a given impact force, the change in volume from the casing deflecting is going to be lower for a larger tire, meaning the change in internal pressure is lower, which would imply a softer ride.



> But you really don't have to—check and see how the load rating of tires go up with volume and recommeded pressure going down. I've got two tractor rear tires that are rock-hard at 17 psi.


Right, that's a great comparison -- because tractor tires have exactly the same construction as road bike tires 

Asad


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## Hank Stamper (Sep 9, 2009)

SystemShock said:


> The 'pro rider' comparison isn't such a good one.
> 
> Most pros weigh like 130-160 lbs, quite often are on tubulars, and have team cars following them around with spare wheels.
> 
> ...


If you trace the comments back you'll see that WIM and I were responding to a blanket statement that wider tires are faster tires.......not recommending what recreational riders should use.


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## nismo73 (Jul 29, 2009)

We need the Mythbusters on this one....


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## heathb (Nov 1, 2008)

I ride 25 Conti's for training as they do take the edge off, they also last a long time and are less prone to flats, but the lighter 20 and 23mm tires have more zip. 

Combine light rims with light tires and you can feel the difference especially going up hill, and hills are where many races are decided.


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## Vibe (Jan 11, 2011)

SystemShock said:


> ^ *pssst* Fixie riders think yer soft 'cuz you use more than one gear. :wink5:
> 
> Anyways, for myself, from much past experience (and bear in mind my riding weight over the years has been in the 210-240 lb range):
> 
> ...


Thanks for linking compasscycle.com. I run with 700x28 tires and I was having trouble finding tires/tubes for my tire size.


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## Sisophous (Jun 7, 2010)

heathb said:


> I ride 25 Conti's for training as they do take the edge off, they also last a long time and are less prone to flats, but the lighter 20 and 23mm tires have more zip.
> 
> Combine light rims with light tires and you can feel the difference especially going up hill, and hills are where many races are decided.


I agree wholeheartedly, the 23mm tires on my all Carbon Trek Madone flies up hills like I’m shot out of a canon. With a little momentum at the start of a hill, I can hold speed up a sharp climb for a half minute.

I’m pretty sure I had 25mm tires on my all steel frame Centurion and that bike did not have the same zip up hills but it was a more comfortable ride and average speed was faster than my carbon bike. 

A more comfortable ride means less fatigue, which means greater efficiency. I feel every crack or bump in the road with my 23mm tires, and it does take its toll on average speed.


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## Fredrico (Jun 15, 2002)

*But wim,*



wim said:


> I guess that's why pros all ride the widest tire they can possibly fit into their frames. With glory and lots of money at stake, who would not want to claim the speed advantages of a 25 over a 23?


When I used to ride tubulars, they all measured slightly over 25mm across, by virtue of their rounder shape as opposed to the U shape of clinchers. So the pros are riding on rounder contact patches, which helps them all the more to go fast! :biggrin5:

Does anybody know any pros who ride on 23C clinchers?


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## Sisophous (Jun 7, 2010)

nismo73 said:


> We need the Mythbusters on this one....


Those clowns on that show would not help. All they do is hook up their gizmos and gadgets and record data. 

The issue is fatigue. How do you measure fatigue in a human? Each person is different, it is the intangible. The 23mm tires cause more fatigue than the 25mm tires but the fatigue factor is different in all of us. At what mile mark would the fatigue show? See what I mean.


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## Pablo (Jul 7, 2004)

No need for Mythbusters ... 

http://www.cyclingnews.com/features/tech-feature-the-work-of-wheel-energy

"Wider tyres roll faster than narrower ones: Many riders have argued for years that narrower tyres – especially on the road – are faster and more efficient than wider ones when in fact, the opposite is true. According to Wheel Energy, the key to reducing rolling resistance is minimising the energy lost to casing deformation, not minimising how much tread is in contact with the ground.

All other factors being equal, wider casings exhibit less casing 'bulge' as a percentage of their cross-section and also have a shorter section of deflected sidewall. How big a difference are we talking about here? For an equivalent make and model of tyre, Wheel Energy claims the 25mm-wide size will measure five percent lower rolling resistance on average – the supposed average limit of human detection – than the more common 23mm-wide one.

Unless you're a pure climber and solely focused on weight, the takeaway message here is that you'll go generally faster on wider rubber even if it's slightly heavier."


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## Doggity (Mar 10, 2006)

Salsa_Lover said:


> they are not.
> 
> 25c tyres are for old clydes on their "comfort" bikes.
> 
> NWWT anyway


Smile when you say that, pardner! WTF do we need 23's for anyway? We ain't tryin' to 'race'. In fact, I'm thinking of going to 28's, since my frame and brakes will allow it.And yes, 25's are definitely way more comfortable, and I sustain fewer flats...way fewer.That alone makes 'em the size of choice for me.


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## herbn (Aug 22, 2009)

well, if it's really a 24, then it's between a 23 and a 25. The thing is sometimes they measure stuf a little different or put it on a wider rim. I think a true measurement is if you took a sample slice of the tire and put it on something flat, you would measure the distance from one bead to the other.


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## cchase86 (Mar 9, 2010)

Pablo said:


> No need for Mythbusters ...
> 
> http://www.cyclingnews.com/features/tech-feature-the-work-of-wheel-energy
> 
> ...


Even that article makes no mention of the pressures used for their testing. I believe the data if the pressures were identical but am not sure what deformation is like on say, a 23c tire at 110psi tire vs a 25c tire at 80-90psi...


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## SystemShock (Jun 14, 2008)

Y'know, it's one of those issues that ppl love to debate, but it's really very dependent on the individual rider. This is why no one can agree.

Another problem is that bike manufacturers seldom if ever spec tires based on rider weight... every size of bike from a 46cm/XXS to a 65cm/XXXL gets the same damn size tire, thus giving the idea that it's a one-size-fits-all 'false choice' in the first place. :skep:

If I were a bike manufacturer, I'd spec the tires on the various model sizes thusly:

Tiny little women sizes (like under 100 lbs): 20c
Little guys and medium-sized women (maybe 125-140 lbs): 23c
Medium sized guys and big women: (160-175 lbs): 25c
'Beeg' guys (well over 200 lbs): 28c


But no one ever does that. Not even Trek, who allegedly 'makes good bikes'.  :nonod:
.


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## SystemShock (Jun 14, 2008)

Vibe said:


> Thanks for linking compasscycle.com. I run with 700x28 tires and I was having trouble finding tires/tubes for my tire size.


No prob. :thumbsup: 
.


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## DIRT BOY (Aug 22, 2002)

This explains it well. But under 180lbs, I feel 23's fell better.

https://www.schwalbetires.com/tech_info/rolling_resistance

*
Which factors affect rolling resistance?*
Tire pressure, tire diameter, tire construction, tire tread and other factors all have an effect on rolling resistance. The higher the tire pressure, the less is tire deformation and thus the rolling resistance. 
Small diameter tires have a higher rolling resistance at the same tire pressure, because tire deformation is proportionally more important, in other words the tire is "less round". Wider tires roll better than narrow ones. 

This assertion generally generates skepticism, nevertheless at the same tire pressure a narrow tire deflects more and so deforms more. Obviously, tire construction also has an effect on rolling resistance. The less material is used, the less material there is to deform. And the more flexible the material is, such as the rubber compound, the less energy is lost through deformation. 

Generally, smooth treads roll better than coarse treads. lugs and wide gaps usually have a detrimental effect on rolling resistance.

*Why do wide tires roll better than narrow ones?*
The answer to this question lies in tire deflection. Each tire is flattened a little under load. This creates a flat contact area. At the same tire pressure, a wide and a narrow tire have the same contact area. 
A wide tire is flattened over its width whereas a narrow tire has a slimmer but longer contact area. The flattened area can be considered as a counterweight to tire rotation. Because of the longer flattened area of the narrow tire, the wheel loses more of its "roundness" and produces more deformation during rotation. 
However, in the wide tire, the radial length of the flattened area is shorter, making the tire "rounder" and so it rolls better. 

*Why do Pros ride narrow tires if wide tires roll better?*
Wide tires only roll better at the same inflation pressure, but narrow tires can be inflated to higher pressures than wide tires. 
However, they then obviously give a less comfortable ride. In addition to this, narrow tires have an advantage over wide ones at higher speeds, as they provide less air resistance. 

Above all, a bicycle with narrow tires is much easier to accelerate because the rotating mass of the wheels is lower and the bicycle is much more agile. 
At constant speeds of around 20 km/h, the ride is better with wider tires. In practice, the energy saving is even greater than in theory as the elasticity of the tires absorbs road shocks, which would otherwise be transferred to the rider and so saves energy.


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## DIRT BOY (Aug 22, 2002)

I also put some Conti GP4000 25's on my bike. They are too tall in the rear and had the add a washer to my rear brakes. I am going back to Schwalbe Ultremo 23's as I fell they roll better at slightly higher pressures and fell just as comfortable with better frame clearance.

I ride great to good roads and weigh in at 168lbs. Now on my steel FG, I use 28's for comfort.


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## TomH (Oct 6, 2008)

Wanna sell the gp 25's? Im not above buying used tires


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## AndrwSwitch (May 28, 2009)

If I don't have a lot of crap with me, I like the handling better with 23mm tires. 24mm tires, I guess - they're GP4000s. I can't tell much of a difference in comfort. I'm limited by the pressure at which my tires squirm in a turn or move around a lot when I climb out of the saddle, not the pressure at which they pinch flat.

If I do have a lot of crap with me or I'm off-road, I'll choose a bigger tire. My commuter has 28s front and back, although honestly I liked the 26 (not sure how big it really was) I had before better.

Without a bag of text books, I weigh mid-150s lately, mid-140s when I'm riding and racing more.


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## jrz1 (Mar 15, 2006)

25 mm tires are faster than 23 mm tires? Case closed? Research is conclusive? Really? Two HUGE problems with all the tests. The first is that every test is done with the tires at the SAME pressure. That is ridiculous and gives the 25 mm tire a built in advantage. 23 mm tires were created to run at an optimal pressure that is higher than the 25 mm tire. Test both tires at their individual optimum pressures and you will find the 23 mm to have equal if not even better rolling resistance numbers. Secondly, all the tests are done on rollers or testing drums not in the real world of riding. In the real world speed is a function of three factors: rolling resistance, weight, and aerodynamics. Science will tell you that at any speed above 15 mph or so the greatest determination of speed is aerodynamics, not weight or rolling resistance. Since the discussion is which tire is fastest there is a distinct advantage to a thinner tire at high speeds. Those who argue that pro's tend to use 23 mm (and often even thinner 21 or 20 mm's in time trials) only because of tradition are really stretching the truth. Pro's lively hood depends on winning and speed. They are not ignorant of science. It's a little arrogant to think that we as recreational bikers know more than the pro's. Pro's ride 23's because they know at the proper pressure they will be faster than 25's. I am confident that a 23 mm tire pumped to its proper pressure will be more efficient at higher speeds than a 25 mm tire pumped to its proper pressure because its aero advantage of a smaller profile and this isn't even mentioning the small advantage it also hold in the weight department. This is the real world not some "test" lab. The only advantage of the 25 mm is better comfort. No arguement there.


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## Fredrico (Jun 15, 2002)

jrz1 said:


> 25 mm tires are faster than 23 mm tires? Case closed? Research is conclusive? Really? Two HUGE problems with all the tests. The first is that every test is done with the tires at the SAME pressure. That is ridiculous and gives the 25 mm tire a built in advantage. 23 mm tires were created to run at an optimal pressure that is higher than the 25 mm tire. Test both tires at their individual optimum pressures and you will find the 23 mm to have equal if not even better rolling resistance numbers. Secondly, all the tests are done on rollers or testing drums not in the real world of riding. In the real world speed is a function of three factors: rolling resistance, weight, and aerodynamics. Science will tell you that at any speed above 15 mph or so the greatest determination of speed is aerodynamics, not weight or rolling resistance. Since the discussion is which tire is fastest there is a distinct advantage to a thinner tire at high speeds. Those who argue that pro's tend to use 23 mm (and often even thinner 21 or 20 mm's in time trials) only because of tradition are really stretching the truth. Pro's lively hood depends on winning and speed. They are not ignorant of science. It's a little arrogant to think that we as recreational bikers know more than the pro's. Pro's ride 23's because they know at the proper pressure they will be faster than 25's. I am confident that a 23 mm tire pumped to its proper pressure will be more efficient at higher speeds than a 25 mm tire pumped to its proper pressure because its aero advantage of a smaller profile and this isn't even mentioning the small advantage it also hold in the weight department. This is the real world not some "test" lab. The only advantage of the 25 mm is better comfort. No arguement there.


Ok, count me one to conceed that the lighter weight of 23Cs climb faster, and inflated to 120 psi or so with a rider weighing less than 145 lbs., probably have nice speed. But the tradeoff, as you said, is comfort, and I'll add slightly less puncture resistance. And under a heavy rider, forget it, 23Cs will crush and have more rolling resistance. System Shock has a great point: the heavier the load, the wider the tire. The weight handicap would be negligible.


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## heathb (Nov 1, 2008)

I rode my rollers this morning and switched between two of my bikes with the same wheelset openpro with DA hubs, same crank 7800 DA and 7810 DA pedals. 

The difference was that one set of wheels had 20mm tires and the other had 25mm tires. 

The 20mm tires were inflated to 120 and the 25mm to 105. 

The rollers are 3" Kreitlers with killer headwind resistance unit.

The 25mm tires felt quite a bit easier at the same gear with same cadence. I was able to ride a gear higher for the same amount of effort with the 25mm tires. So there might be something to this 25mm tires rolling with less resistance.


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## jermso (May 13, 2009)

looks like the pros were already leaning towards 25mm since last year.

http://www.bikeradar.com/gallery/article/pro-bike-michael-rogers-htc-columbia-scott-addict-26318/


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## mtbbmet (Apr 2, 2005)

jrz1 said:


> 25 mm tires are faster than 23 mm tires? Case closed? Research is conclusive? Really? Two HUGE problems with all the tests. The first is that every test is done with the tires at the SAME pressure. That is ridiculous and gives the 25 mm tire a built in advantage. 23 mm tires were created to run at an optimal pressure that is higher than the 25 mm tire. Test both tires at their individual optimum pressures and you will find the 23 mm to have equal if not even better rolling resistance numbers. Secondly, all the tests are done on rollers or testing drums not in the real world of riding. In the real world speed is a function of three factors: rolling resistance, weight, and aerodynamics. Science will tell you that at any speed above 15 mph or so the greatest determination of speed is aerodynamics, not weight or rolling resistance. Since the discussion is which tire is fastest there is a distinct advantage to a thinner tire at high speeds. Those who argue that pro's tend to use 23 mm (and often even thinner 21 or 20 mm's in time trials) only because of tradition are really stretching the truth. Pro's lively hood depends on winning and speed. They are not ignorant of science. It's a little arrogant to think that we as recreational bikers know more than the pro's. Pro's ride 23's because they know at the proper pressure they will be faster than 25's. I am confident that a 23 mm tire pumped to its proper pressure will be more efficient at higher speeds than a 25 mm tire pumped to its proper pressure because its aero advantage of a smaller profile and this isn't even mentioning the small advantage it also hold in the weight department. This is the real world not some "test" lab. The only advantage of the 25 mm is better comfort. No arguement there.


First of all, what's ideal pressure? You seem to know allot about what pro's do and think, so what pressure do you think pro's ride?
Ideal pressure for a 23mm tire is just over 100psi for a 160lb rider, less for a 25. The biggest issue that you seem to have sidestepped is that pro's run tubular tires, and for the most part we are talking about clinchers. Pro's run there tubulars at pressures between 70-100 psi depending on conditions. These are pressures you could never run a clincher @ because you would be constantly pinch flatting. For someone who is 160lb to ride a 23mm clincher without pinchflatting at every railway crossing, the pressure HAS to be over 105psi. So lets call that ideal. The same rider can ride a 25mm tire @ 90psi without pinchflatting, so lets call that ideal. Under any real world situation, a 25mm @ 90 will have less crr than a 23mm @ 105psi. That's fact.
Pro's ride 23's because they are tubulars, and they are lighter. Leave them out of the discussion, because it is unrelated.
And as to aerodynamics. Can you explain to me why pretty much every high end wheel manufacturer is moving to wider profile rims if narrow is "scientifically" faster? Because there is more involved that just tire width.
Your post is full of assumptions and mis-information based on your version of "science". In the future, please don't add to the myths.
So I say again, but a little clearer this time. 25mm clinchers are faster than 23mm clinchers. That is fact.


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## mtbbmet (Apr 2, 2005)

http://www.cyclingnews.com/features/tech-feature-the-work-of-wheel-energy
read this.


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## AndrwSwitch (May 28, 2009)

Link's not working.


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## terryansimon (Oct 8, 2009)

AndrwSwitch said:


> Link's not working.


try this instead. http://tinyurl.com/6l88kle


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## jrz1 (Mar 15, 2006)

mtbbmet said:


> First of all, what's ideal pressure? You seem to know allot about what pro's do and think, so what pressure do you think pro's ride?
> Ideal pressure for a 23mm tire is just over 100psi for a 160lb rider, less for a 25. The biggest issue that you seem to have sidestepped is that pro's run tubular tires, and for the most part we are talking about clinchers. Pro's run there tubulars at pressures between 70-100 psi depending on conditions. These are pressures you could never run a clincher @ because you would be constantly pinch flatting. For someone who is 160lb to ride a 23mm clincher without pinchflatting at every railway crossing, the pressure HAS to be over 105psi. So lets call that ideal. The same rider can ride a 25mm tire @ 90psi without pinchflatting, so lets call that ideal. Under any real world situation, a 25mm @ 90 will have less crr than a 23mm @ 105psi. That's fact.
> Pro's ride 23's because they are tubulars, and they are lighter. Leave them out of the discussion, because it is unrelated.
> And as to aerodynamics. Can you explain to me why pretty much every high end wheel manufacturer is moving to wider profile rims if narrow is "scientifically" faster? Because there is more involved that just tire width.
> ...


I'm not desiring to start a flame war. Just want to debate the idea that as you and others have declared that it is a settled fact that 25 mm clinchers are "faster" than 23 mm clinchers. Let's start with areas I think we agree on. AT THE SAME PRESSURE a 25 mm clincher has lower rolling resistance (note I didn't say is "faster", were just talking rr), also it will be a more comfortable ride and is capable of performing at lower air pressures than a 23 mm. I also agree and appreciate you mentioning that most pro's use tubular rather than clinchers. That is a good point (and one I like since I personally ride tubulars, but the tubular vs. clincher debate is for another topic). Now where I would disagree. According to Sheldon Brown, Schwalbe tires, and Michelin's recommendations (go the their websites and see their charts) a 150 to 160 lb. rider would find the ideal psi for a 23mm clincher to be between 110 to 120 psi, not 105. Your 90 psi recommendation for a 25 mm tire is spot on according to those sources. Now would a 25 mm at 90 psi have lower rr than a 23 mm at 115 psi? In no way am I going to automatically concede that. It is a debate that is very difficult to prove because every comparison that is published and reputable always compares the different width tires at THE SAME PRESSURE. The very best, most complete, and probably the best controlled study was done by Al Morrison at Biketechreview: 
http://www.biketechreview.com/tires_old/images/AFM_tire_testing_rev9.pdf
While an awesome study, he like the others compared all widths at the same pressure. Note the final table at the end of his study where he compares the effect of increasing pressure on rolling resistance. It is rather dramatic in how higher pressures reduce rr. Secondly to say that because high end wheel makers are now making wider rims somehow proves that wider tires have better aerodynamics doesn't make sense. They are making wider rims because wider rims tend to be stronger and more comfortable and more versatile in that they can handle both thin tires and wide tires. A wide rim helps a wide tire be more aerodynamic than if mounted to a thin rim, but it doesn't make it more aerodynamic than a thinner tire with a smaller frontal area. Here it is science. The basic formula for drag (remember high school physics), and common sense tells us that something with a smaller frontal area will have less drag than something with a bigger frontal area. And finally, although I think it is a relatively small factor, the thinner version of the same tire will always weigh less than its wider version which may not effect top speed but certainly could have an impact on acceleration and climbing. In no way am I willing, based on these factors, to concede that it is a fact that 25 mm tires are "faster" than a 23 mm tire.


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## jrz1 (Mar 15, 2006)

Interesting link. I had read that article a few weeks back. But, unless we learn that they tested the different width tires at different pressures all we have learned is what we already knew and all agree on - that wider tires at the SAME PRESSURE have a lower rolling resistance than thinner tires at that same pressure. Again, it talks about reduced rolling resistance which is only one component of the three things that determine a tires speed: rolling resistance, weight, and the biggest factor at higher speeds - aerodynamics. Probably the truth lies in compromise. An earlier post listed a link that talked about one pro team that was running 25mm in the rear and a thinner (probably 23mm but could have been thinner) up front. Wouldn't that make sense. Thinner up front because of aerodynamic advantage of a thinner tire and wider in the rear where aerodynamics aren't as great a factor but where the increased width would give more comfort and perhaps a reduced rolling resistance. Makes sense to me.


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## D&MsDad (Jul 17, 2007)

Performance has the Vittoria Rubino Pro Slick for $30 in a 25mm size (no idea what the actual size is). 

The combo of decent ride, decent durability and low cost make this is my favorite tire. I like the ride better than the Michelin Pro Race, it is fairly durable (slightly less mileage than the Pro Race IME, but similar frequency of flats) and it is slightly easier (but still a PITA) to get onto a Campy rim. And, it is inexpensive.

Thanks for this thread, I need new tires soon and this looks like a good buy. I've always bought the 23mm before because that was what was available. I'm interested in trying the 25mm.





----------------------------------------------


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## Tahoe Gator (May 28, 2002)

No way 25 are faster than 23. By that logic then 28 would be faster still. Or 30! Wider equals more contact with the road equals more drag. So long as the tire isn't so thin as to slice into the road, skinner is faster. Just look at other sports and technologies. Prius cars have skinny tires for a reason. Pine wood derby cars with skinny tires go faster. Etc. Etc. But there is a practical limitation to how skinny before other factors like comfort, safetey, handling, etc., outweigh going skinnier.


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## asgelle (Apr 21, 2003)

Tahoe Gator said:


> No way 25 are faster than 23. By that logic...


Logic can't overcome data. Rolling resistance, aero drag, gravity; those are the forces controlling speed for a given power input to a bike. Plug in the numbers for different tires and you'll have your answers. Bikes aren't cars.


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## AndrwSwitch (May 28, 2009)

Tahoe Gator said:


> Wider equals more contact with the road equals more drag.


Given that we're talking about something flexible with a rounded profile, contact patch is a function of pressure. The tire shape can change the shape of the contact patch, but not it's area - that's what pressure is.

The point of all the research favoring wide tires is that they don't have to deform as much in order to have the same size contact patch as a narrower tire at the same pressure. Everybody's criticism of that research is that people typically run higher pressure in narrower tires, causing less deformation and less rolling resistance. Which tire ultimately experiences less rolling resistance is debatable, especially when you add questions about what tire pressure is reasonable, comfort, etc.

So really, it's an optimization problem - what pressure do I want for comfort? Is it different for different size tires? What does it do to rolling resistance and flat protection? What about air resistance? Different sizes favor different things, and that's why this is such an internet debate, rather than everybody just running 23s or everybody running 32s.

It's cool that the rolling resistance conclusions are available, but in order to make a really informed decision, the data would need to be available too, as well as data about air resistance. Then it would actually be possible to decide this stuff scientifically, rather than by instinct, logic (How far did that get Aristotle in understanding physics?) anecdotes, etc.

I think that if nothing else has been "proved," it's that the difference in rolling resistance is slight. So for a recreational cyclist or lower-category racer, deciding between a 23 and a 25 is maybe better left to other differences between the sizes. I'll keep choosing based on handling - that's what makes my bike fun for me.  Other people can choose based on what makes sense to them. It doesn't really effect my ability to have fun riding with them unless they go to a really large size, like a 30 or 32, and even then, not very much.


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## nOOky (Mar 20, 2009)

If someone took the time to mount and fill to an equal pressure and then measure the width and height of all the 23mm and 25mm tires out there it would be a valuable chart indeed. Then add another factor for the rim width, and say tire pressures at 5 different settings and then you'd have a useful comparison. Until then most of us only go by feel, which is usually so subjective as to be worthless. (I just replaced my flat old tired 23mm tires for new 25mm tires with less pressure and they ride so much better-duh)


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## danl1 (Jul 23, 2005)

Sisophous said:


> I like a poster who has spunk and speaks his mind.
> 
> I am considering getting the 25c just to experiment with it. Speed isn’t such a big deal, you can only ride so fast where I go without putting yourself in danger. On my 30 speed Trek Madone, I only use gears 11-20 for all terrain, including hills.
> 
> What is the point of gears 21-30 unless you want to go over 30 mph.


Please, please, PLEASE tell us that you don't mean that you ride in the middle chainring all the time, and consider that "gears 11-20."


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## Tahoe Gator (May 28, 2002)

danl1 said:


> Please, please, PLEASE tell us that you don't mean that you ride in the middle chainring all the time, and consider that "gears 11-20."


...very obviously there are riders who are looking to go faster to be more competitive -- in races or their local fast group ride -- and those happy to do a nice ride and be comfortable doing it. But, it does seem that the subject of 25 or 23 being faster is more the former...if you're not worried about ever going over 30 mph, not sure why you'd be concerned with tire width beyond differences in comfort...unless you're talking about 30 gears as in bikes with knobbies  ...in which case mtbr.com would be the place to discuss


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## superg (May 9, 2010)

This looks exactly like a thread fueled by voodoo science. It's obvious 25c tires are faster than 23c tires only if they're red or if the rider of said 25c tires is Fabian Cancellara and the rider of the 23c is me.


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