# 700 x 20c Clinchers ??



## brushman (Jul 17, 2006)

Hey Folks,

Looking for opinions......

I'm a serious recreational rider, no sanctioned racing currently, but training hard. I'm considering going to a thinner clincher road tire, 700 x 20c, (lighter, less rolling resistance, etc...), something like the _Vittoria Open Corsa EVO KS_, as opposed to the more traditional 23c. For those of us who would like to approach the performance of tubulars while staying on clinchers, 20c tires may provide that opportunity. (Plus, the obvious cost benefits.) Does this sound worth while? And, do you think the performance benefits will be noticable? Durability an issues? I've read several views on 20c tires riding harsh, but would appreciate any additional insight. By the way, I'm 5'6" and weigh 130 lbs.

Thanks!


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## MR_GRUMPY (Aug 21, 2002)

At 130 pounds, I see no problems. Just keep them at 120 psi


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## rruff (Feb 28, 2006)

:idea:


brushman said:


> I'm considering going to a thinner clincher road tire, 700 x 20c, (lighter, less rolling resistance, etc...)


They will be slightly lighter... but the rolling resistance will be slightly higher. Even on a steep climb the larger tire will be faster.

The biggest issue is if you are using aero or semi-aero rims... most of them work better with narrow tires, so the smaller tire ends up being faster on the flat.

Don't make the mistake of pumping them up too high... unless you are on a smooth track. High pressures on real roads increase vibration losses more than they decrease rolling losses. The optimum is probably less than 100psi for you even with a narrow tire... maybe a lot less... just enough pressure to prevent pinch flats.


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## brushman (Jul 17, 2006)

rruff,
Thanks for the insight. Could you please clarify_..."but the rolling resistance will be slightly higher. Even on a steep climb the larger tire will be faster."_ Even with higher pressure, smaller contact patch? Also, doubtful I would get the full benefit of the narrow tire if I ran less than 100psi, many manufacturers recommend minimum of 115psi! Perhaps you could elaborate....
(Rims - Mavic Ksyrium SL wheelset.)
Thanks!


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## tobu (Dec 19, 2004)

do a search. it's common knowledge that at any given air pressure, the wider tire has less rolling resistance than a narrow tire. the reason why most racers use a 23 is that it's the probably the best combination of rolling resistance, aerodynamics, shock absorption, cornering grip, wear, etc... 

On a smooth course TT with little cornering, a 700x20 can make sense. You can generally inflate narrower tires to higher pressures, it's lighter, and the tire width is usually pretty close to the rim width for optimum aerodynamics. But in most real world conditions of less than perfect pavement and non-straight line riding, 23's are the way to go.


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## carbfib (Jul 15, 2005)

brushman said:


> Hey Folks,
> 
> Looking for opinions......
> 
> ...


 how much have you ridden on 23s? do you only ride on tracks? [the real place for 20s]


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## brushman (Jul 17, 2006)

Guess more scientific knowledge in tire physics and aero-dynamics would be helpful here in regards to rolling resistance and performance. The basic idea I'm exploring is to utilize the _optimum _tire size that would provide the best overall performance based on rider size and weight...not just the stock, most commonly used roadtire size - 23c. I mean, relatively speaking, we are all built differently, and weigh different amounts, so why the same sized tires? Why should I, at 5'6" & 130lbs, ride the same size tire as someone 6' & 190lbs? As most serious cyclists striving for the "perfect ride" constantly analyze practically every part of their machines (frame size, components, etc...) for weight and efficiency, I would think tire size would be an area worth optimizing as well. Am I missing something here?


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## carbfib (Jul 15, 2005)

brushman said:


> Guess more scientific knowledge in tire physics and aero-dynamics would be helpful here in regards to rolling resistance and performance. The basic idea I'm exploring is to utilize the _optimum _tire size that would provide the best overall performance based on rider size and weight...not just the stock, most commonly used roadtire size - 23c. I mean, relatively speaking, we are all built differently, and weigh different amounts, so why the same sized tires? Why should I, at 5'6" & 130lbs, ride the same size tire as someone 6' & 190lbs? As most serious cyclists striving for the "perfect ride" constantly analyze practically every part of their machines (frame size, components, etc...) for weight and efficiency, I would think tire size would be an area worth optimizing as well. Am I missing something here?


Sure it would be worth getting the most out of. but not xcessively. Tires only have a certain (limited) value. [But] Frames, components --- are OUR long-term investments. Our >reason< in why We do the cycling. Without those 2 categories, We wouldn't be doing cycling. When they get discontinued in production; or future availability. We raise fear. 'Cause we know what to go wrong. /// But with tires, there's many more options. When ones we like are out of production, we don't raise concern. There's always better ones coming out.


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## tobu (Dec 19, 2004)

brushman said:


> Guess more scientific knowledge in tire physics and aero-dynamics would be helpful here in regards to rolling resistance and performance. The basic idea I'm exploring is to utilize the _optimum _tire size that would provide the best overall performance based on rider size and weight...not just the stock, most commonly used roadtire size - 23c. I mean, relatively speaking, we are all built differently, and weigh different amounts, so why the same sized tires? Why should I, at 5'6" & 130lbs, ride the same size tire as someone 6' & 190lbs? As most serious cyclists striving for the "perfect ride" constantly analyze practically every part of their machines (frame size, components, etc...) for weight and efficiency, I would think tire size would be an area worth optimizing as well. Am I missing something here?


Right. I'm 163cm, 61 kg. That's why you should stick with the 23. Anyone who's 190lb might consider using 700x25. This is what I suggest for you -- a supple 700x23 racing tire with a high quality light weight tube. Run your tires at 6-7 atm depending on the road/weather conditions, usage, riding skill, and tire type. Some riders have a little more pressure in the rear compared to the front.


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## Keeping up with Junior (Feb 27, 2003)

*Stay with 23c*



brushman said:


> ...Why should I, at 5'6" & 130lbs, ride the same size tire as someone 6' & 190lbs?...


My wife weighs 105 and prefers the ride comfort as well as performance of 23c tires. If you really dig around on the net I think there are some studies that support the better rolling resitance of the 23c tires. On our tandem I was using a 23c up front because of a brake clearance issue and recently switched to a 25c up front and found it a better fit for the heavier bike. As Tobu noted, unless you are on a smooth TT course or in a velodrome stick with what works well which is a 23c.


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## alienator (Jun 11, 2004)

brushman said:


> Guess more scientific knowledge in tire physics and aero-dynamics would be helpful here in regards to rolling resistance and performance. The basic idea I'm exploring is to utilize the _optimum _tire size that would provide the best overall performance based on rider size and weight...not just the stock, most commonly used roadtire size - 23c. I mean, relatively speaking, we are all built differently, and weigh different amounts, so why the same sized tires? Why should I, at 5'6" & 130lbs, ride the same size tire as someone 6' & 190lbs? As most serious cyclists striving for the "perfect ride" constantly analyze practically every part of their machines (frame size, components, etc...) for weight and efficiency, I would think tire size would be an area worth optimizing as well. Am I missing something here?


Well, somewhere there was a study or two that indicated the optimal tire size with which to minimize rolling resistance and aerodynamic penalties was a 23. The benefits of the 23, in addition to better rolling resistance and minimal aero penalty compared to a 20, are that you can run at lower pressure. The lower pressure means you end up with tires that have a lower spring rate which means a less harsh ride. A more comfortable ride, in most cases, will result in a rider that is less tired over a long distance and one that can perform a bit better at the end of that long distance. Also, the lower pressure will mean you get a larger contact patch which means better grip which means being able to go throw corners faster and safer. The larger contact patch makes the tire less likely to lose traction due to crap on the road. The 23 will also be less likely to pinch flat.

Unless your on a glass-smooth surface, like a velodrome has, then there really is no upside to using 20's.


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## carbfib (Jul 15, 2005)

tobu said:


> Right. I'm 163cm, 61 kg. That's why you should stick with the 23. Anyone who's 190lb might consider using 700x25. This is what I suggest for you -- a supple 700x23 racing tire with a high quality light weight tube. Run your tires at 6-7 atm depending on the road/weather conditions, usage, riding skill, and tire type. Some riders have a little more pressure in the rear compared to the front.


Technically (for Me) that's a higher concern --- really -- when I change wheels: like Open Pro to Hyperon, on the same bike. From metal to c-f. As I've done on one of My bikes. Michelin not work its optimum @ the max recommended psi; it must be a bit above it.


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## brushman (Jul 17, 2006)

Very interesting comments! While I see your perspectives, I can't help but continue to believe that proportionality and rider weight/size ratio must play a role in tire handling and performance. Why do you suppose most tubulars, often the choice of hardcore professional racers, are in the 20-22c range?


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## Karbon (Oct 13, 2005)

alienator said:


> Well, somewhere there was a study or two that indicated the optimal tire size with which to minimize rolling resistance and aerodynamic penalties was a 23. The benefits of the 23, in addition to better rolling resistance and minimal aero penalty compared to a 20, are that you can run at lower pressure. The lower pressure means you end up with tires that have a lower spring rate which means a less harsh ride. A more comfortable ride, in most cases, will result in a rider that is less tired over a long distance and one that can perform a bit better at the end of that long distance. Also, the lower pressure will mean you get a larger contact patch which means better grip which means being able to go throw corners faster and safer. The larger contact patch makes the tire less likely to lose traction due to crap on the road. The 23 will also be less likely to pinch flat.
> 
> Unless your on a glass-smooth surface, like a velodrome has, then there really is no upside to using 20's.



Here is a reason for 20's....


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## Guest (Jul 18, 2006)

Back in the day ( the '80's) when I was young and racing I tried what at that time was supposed to be the way of the future.

A Continental clincher that was available in both 18 and 20 ( the Grand Prix I think).

It rode like crap, it was harsh, unyeilding and pinch flatted like mad. Kind of like riding a buckboard.

I always thought those tires were a good advertisement for either 23's or good tubulars. Sadly silks are no longer available.


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## alienator (Jun 11, 2004)

carbfib said:


> Technically (for Me) that's a higher concern --- really -- when I change wheels: like Open Pro to Hyperon, on the same bike. From metal to c-f. As I've done on one of My bikes. Michelin not work its optimum @ the max recommended psi; it must be a bit above it.


NO tire works at its optimum when operated at the max recommended psi. In fact, if you're running tires at or above that--unless you're riding on a velodrome--your not running as efficiently as you could. That is a fact. High psi only feels fast because the tires bumps all over the place. I guarantee you that you are not getting the most out of your tires.


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## alienator (Jun 11, 2004)

Karbon said:



> Here is a reason for 20's....


I'll give you $100 if you can show that 700x23 tires won't work in that frame. You won't be able to.


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## Karbon (Oct 13, 2005)

alienator said:


> I'll give you $100 if you can show that 700x23 tires won't work in that frame. You won't be able to.


I think it depends on whose 23c tires you want to fit.

I don't have one of those frames, so I can't show it. I can show you how if I use anything other than a Veloflex Pave I risk scraping the back of a carbon tube on my Paduano though....Vredestein and Vittoria 23c's won't fit without rubbing. it's a combination of short stays and a 72deg seat tube angle...


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## tobu (Dec 19, 2004)

brushman said:


> Very interesting comments! While I see your perspectives, I can't help but continue to believe that proportionality and rider weight/size ratio must play a role in tire handling and performance. Why do you suppose most tubulars, often the choice of hardcore professional racers, are in the 20-22c range?


Without getting into a discussion of tubulars vs. clinchers, most tubulars used on the road are 22 or 23mm. A Vittoria CX at 22mm is pretty much the same width as most 23mm clinchers. Tubulars also usually have a rounder profile (although I think some people argue otherise). Tubulars are harder to pinch flat so you can run a narrower tire. Tubulars usually have more supple casings (higher TPI) so they tend to have better shock absorption and cornering grip, so you can get away with a slightly narrower tire.

Like I said before, I think you're right about proportionality, but my opinion is most riders are undersizing their tires. For many applications, bigger riders should probably be on 25's or 28's.


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## alienator (Jun 11, 2004)

tobu said:


> Without getting into a discussion of tubulars vs. clinchers, most tubulars used on the road are 22 or 23mm. A Vittoria CX at 22mm is pretty much the same width as most 23mm clinchers. Tubulars also usually have a rounder profile (although I think some people argue otherise). Tubulars are harder to pinch flat so you can run a narrower tire. Tubulars usually have more supple casings (higher TPI) so they tend to have better shock absorption and cornering grip, so you can get away with a slightly narrower tire.
> 
> Like I said before, I think you're right about proportionality, but my opinion is most riders are undersizing their tires. For many applications, bigger riders should probably be on 25's or 28's.



Good post, except for the rounder profile bit. 

You have to remember, too, that tubulars, in general, have more rolling resistance than clinchers. Granted, there are several factors in rolling resistance, but tire size is one of 'em. Why tubulars are predominantly more narrow than clinchers, I don't know. It could be historical inertia. It could be mythology. I have clinchers and tubies. The clinchers are 25mm tires and the tubies are 21mm Vittoria EVO Corsa CX skins. I like the way the tubies and their wheels roll, but I can't specify why. They're on 46mm deep rims, so I suspect the aero advantage could be larger than the rolling resistance penalty. At any rate. The 25mm clinchers and their wheels roll nicely, too. "Rolling nicely," though, is a completely subjective qualification.


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## Karbon (Oct 13, 2005)

tobu said:


> Without getting into a discussion of tubulars vs. clinchers, most tubulars used on the road are 22 or 23mm. A Vittoria CX at 22mm is pretty much the same width as most 23mm clinchers. Tubulars also usually have a rounder profile (although I think some people argue otherise). Tubulars are harder to pinch flat so you can run a narrower tire. Tubulars usually have more supple casings (higher TPI) so they tend to have better shock absorption and cornering grip, so you can get away with a slightly narrower tire.
> 
> Like I said before, I think you're right about proportionality, but my opinion is most riders are undersizing their tires. For many applications, bigger riders should probably be on 25's or 28's.


My fave training tire is the 24c Vittoria Open Pave. Can't fit them in my regular training frame though (doh!). I'm over 6' and 195lbs....it's being used as a good excuse for another bike build... 

I don't think width is the issue as much as height is, tires of different makes have different heights, and that affects pocket size (the room the tube has to inflate into) and handling as much as anything (remember the Panaracer Rapide tubular?). Tubulars tend to have a lower height than the typical 23c clincher does, if you take a Vittoria CX and an Open CX 23c, they measure differently in height by quite a margin, enough that the equal in size tubular-clincher is the 20c.


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## brushman (Jul 17, 2006)

So...what's your recommendation? 23c or 20c clincher?


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## Keeping up with Junior (Feb 27, 2003)

*23c*



brushman said:


> So...what's your recommendation? 23c or 20c clincher?


Well if you have been following the discussion and did not get distracted when someone drifted off in the professional/tubular drift the consensus is *23c* clincher with the pressure adjusted appropriately for your weight and riding conditions. If you really want to ride a 20c then ignore the advice you got here and go buy one and ride it.


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## Karbon (Oct 13, 2005)

brushman said:


> So...what's your recommendation? 23c or 20c clincher?



22c Veloflex Pave... 

Actually it's all subjective. I'd suggest 23c, but I would also say try other sizes and makes (sizes differ between makes a lot) if you want to. You'll find what suits you and don't forget to play with tire pressures (no matter what the tire size I use 110-125psi depending on make based on my own experience and road conditions). Have fun with it. :thumbsup:


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## tobu (Dec 19, 2004)

alienator said:


> Good post, except for the rounder profile bit.


I think I was referring to you when I said some people don't feel tubulars are rounder. I personally haven't measured or looked closely enough to see if that is the case or not. And I like both clinchers and tubulars.


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## brushman (Jul 17, 2006)

Thanks everybody for your thoughts, they've been helpful. However, as you may have guessed, I'm most curious about the 20's, so, I'll probably give them a try. Having ridden 23s for years, I'm up trying something new. I may regret the choice, but who knows? They're only tires....


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## carbfib (Jul 15, 2005)

brushman said:


> Thanks everybody for your thoughts, they've been helpful. However, as you may have guessed, I'm most curious about the 20's, so, I'll probably give them a try. Having ridden 23s for years, I'm up trying something new. I may regret the choice, but who knows? They're only tires....


I've kept in Mi Mindset the entire time ---- that this be the perfect chat setup by one who collect info for a tire manufacturer. All the perfect questions are asked in lure by this person, and the responses victimized by the members. I simply tried Mine, for the reason to see how extennnnsive this was going to go. He had to keep asking more&more questions -- as he kept thanking Us members for answering the previous ones. Thanking US in the xact context: in that he was not gonna ask anymore questions. All that was missing = the wording that he was finished with the thread. Not gonna ask Us anymore questions. As he aleady seems to have many of his own answers, already.


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## den bakker (Nov 13, 2004)

carbfib said:


> I've kept in Mi Mindset the entire time ---- that this be the perfect chat setup by one who collect info for a tire manufacturer. All the perfect questions are asked in lure by this person, and the responses victimized by the members. I simply tried Mine, for the reason to see how extennnnsive this was going to go. He had to keep asking more&more questions -- as he kept thanking Us members for answering the previous ones. Thanking US in the xact context: in that he was not gonna ask anymore questions. All that was missing = the wording that he was finished with the thread. Not gonna ask Us anymore questions.


The question is not if you are paranoid. It's if you are paranoid enough.....
*gasp* my computers has just been pinged from michelin.com 
RUN 
RUN 
TRASH THE DRIVES AAAAAARGHHHHH


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## brushman (Jul 17, 2006)

Umm....glad you think my questions are _perfect_...I'll take that as a compliment. However, you're being a bit paranoid in thinking that I represent some tire manufacturer, which I do not. Nope...just curious about 20c sized tires, and trying to focus the thread on the various issues of concern to me. With many views stated, why continue to beat the subjective dead horse? Thus, end of thread, atleast for me. _And_, by the way, thanking people for sharing their views is just a matter common courtesy...something we often neglect, especially online. Cheers!


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## carbfib (Jul 15, 2005)

brushman said:


> Umm....glad you think my questions are _perfect_...I'll take that as a compliment. However, you're being a bit paranoid in thinking that I represent some tire manufacturer, which I do not. Nope...just curious about 20c sized tires, and trying to focus the thread on the various issues of concern to me. With many views stated, why continue to beat the subjective dead horse? Thus, end of thread, atleast for me. _And_, by the way, thanking people for sharing their views is just a matter common courtesy...something we often neglect, especially online. Cheers!


!Cheers!!


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## danl1 (Jul 23, 2005)

Give 'em a go! 

In my experience you won't see the difference you are hoping for, but you're not me, so who knows. 

Just as a thought experiment, imagine grinding the hooks off the rims and painting on a bit of some rubber compound, dispensing with that whole inner tube silliness entirely. Essentially, taking the argument to the extreme. The result? A bike that won't hold a corner, and is slower than hell because every piece of gravel in the asphalt lifts the bike rather than simply running under the flexion of the proper tire. 

Now, you are thinking correctly that there is some difference available because of your lighter weight, and you could use that to either run narrower tires or to run lower pressure in 23's. Either choice would run more efficiently, but the 23's run at a lighter pressure will probably corner better than the 20's, unless you get rims that are sized more appropriately to the 20's - something that's hard to find. 

Regarding the tubular sidetrack, the measurement standards are about as accurate as women's dress sizes, and the two types aren't directly comparable. Certain 22 tubulars could easily be as big as some of the tighter 25 clinchers, depending on the rims.


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## pardue10 (Sep 26, 2005)

I had the same thoughts as you about 20mm tires and got a pair of Pro Race to try. I have about worn them out. Comparing them to 23mm Evo Vittorias, I like the Evos better. The 20s were a little finicky cornering at first. I got used to them and haven't had a problem but 23s corner better. I pump mine up to 120 and they aren't harsh. I have them on a set of Ks and a Vortex. I think the croud is right, get a good high end race tire like the Evo. The 20s are more Aero, but that is probably the only advantage.


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