jppe

Got this information as a part of an email from one of my bike part suppliers...........



The skinnier and higher pressure the tires, the faster the bike, right? Well, no, actually. Speed comes down to a variety of factors, and even many pro road riders these days are choosing wider rubber for training and racing.

So what should you be considering when you're weighing your tire width options? First up is, well, weight. A 20mm or 23mm tire is just plain less rubber than a 25mm tire -- so it will weigh less than the wider tire, resulting in lower rotational weight, which means you'll be able to spin your wheels up to speed that much quicker.

But weight isn't the only thing to consider. Rolling resistance, aerodynamics, grip, and ride quality all play an important role in how fast you ride. 23mm tires still have 25mm tires beat in terms of aerodynamics, but with the newest aero rims, which tend to be wider than previous incarnations, that advantage is negligible, and 25mm tires perform better in pretty much every other way.

You mean 25mm tires actually offer less rolling resistance than 23mm tires? How does that work? Yes, it's true! A 25mm tire at slightly lower pressure has a wider contact patch that actually allows the tire to conform to imperfections in the road surface much more effectively than a hard, bouncy 23mm tire, resulting in lower frictional forces and, yup, a faster roll. That greater contact patch also gives 25mm tires better grip through corners, meaning you can roll through them at higher speeds with greater confidence. And, of course, wider tires provide a softer, more comfortable ride -- which doesn't seem related to speed until you consider that the better you feel, the harder you can push.

So consider widening the gap between you and the competition by widening your tires. Our favorite racing and training tires are all available in 700c x 25mm sizes.

bruce19

I went from 23 to 25 last year on my Masi. Liked the increased comfort but I was never really uncomfortable with the 23s. Couldn't tell you if one rolls better than the other. This year I bought a Guru steel that came with 23s. It was a lightly used bike. Went to 25s about 2 weeks ago and ran into frame clearance issues. Up on my work stand the rear 25 spun easily but with almost no space between tire and frame. When on the bike the tire bulged just enough to rub on the frame. Off with the 25s and on with the 23s.

fietsbob

2mm YMMV .. 28 is OK too spend more for better made tires..

volosong

Almost dumped a new Pinarello frame because every little expansion joint or crack in the asphalt sent a sharp jolt through the entire bike and into my body. This was with 23mm tires. As one last effort to mitigate the harshness, I tired 25mm tires. That FP-6 is now my most favorite and most comfortable bike. I've switched to 25mm tires on all my bikes.

Bill Kapaun

I like skinny tires, but at around 240 lbs., 23's give me too much "road buzz" on rough textured pavement which numbs my hands in a short time. I ride 26mm's (which actually measure 25 on my skinny rims) and it's much better. Still a little harsh, but I'll live with that.
The extra width also gives me a bit more leeway RE: tire pressure. I had to top of the 23's everyday, whereas I can skip a day with the 25's if I want.

JanMM

25? That's still a skinny tire.
Nothing smaller than 32 on my bikes. If road surfaces were all Perfect, I'd be rolling thinner tires. But not much thinner.

DnvrFox

Tried 19's, 20's, 23's and 25's - 25's are what I use - especially better for a bit of gravel road or sand - noticeable positive difference.

Zinger

23s were a little harsh riding on my 1st stiff Trek 970. I stopped using them even on century wheels back in the '80s. If you wannabe faster, work on the motor.

mapeiboy

5'8" , 127 lbs , on 23s for years no problem .

wphamilton

I skip a week with 25's, sometimes two weeks.

25's are the slimmest that I've used. Honestly, if I didn't know whether I was riding 25 or 28 width I couldn't tell you from the ride. The quality of tire makes a bigger difference in the more affordable range of tires. I doubt that 23's would differ in that, other than pumping them up to higher pressures.

But if wider tires are almost as fast, more versatile and better comfort, then WHY were so many people riding 19's or 20's not so long ago?

chasm54

"Almost as fast" gives you your answer, I think. Really the only people riding riding 19s or 20s, in my experience, were those who raced.

The wider tyre has less rolling resistance only if inflated to a similar pressure as the narrower one, which negates some of the difference in comfort. And unless it's installed on a wider rim, which is a very recent innovation, it's a tad less aerodynamic as well as heavier.

Personally I still use 23mm tyres on my road bikes. I'm not uncomfortable and have just seen no reason to change. And if one is after comfort at the expense of speed, and has the clearances, why stop at 25? Why not 28s?

jppe

I've used 23's exclusively (except for a 19 or 20 on the front tire of my TT bike) and have found that they work great for me. I've ridden them on asphalt, concrete, gravel and dirt. Depending on the wheels and frame I'm riding, I might run a little lower air pressure.

I was thinking that maybe the retailer had an excess inventory of 25's and thus the purpose of the email**********???

wphamilton

I can't really feel the difference so I'm wondering why switch either way. A little narrower in the wind, a little less weight. Logically I'll switch to 23's on my next tire

camelopardalis

Scientific testing does confirm that wider tires roll faster. Can you argue with this analysis?

Bicycle tires - puncturing the myths - BikeRadar

jimmuller 

I have 23s, 25s, a 28, a 32, and 32 on the tandem. I can feel the difference in weight. It's almost subtle, and I'm not racing anyone, not even myself. But I like the feel of the lighter tire and the fact that it at least seems to spin up to speed faster. I run all my tires a max rated pressure and I think they roll better that way. Some people argue that it isn't so. They don't convince me, but I don't convince them either. YMMV.

martianone

A few years ago, had an AL road bike; the ride was a touch stiff - 25 mm tires nicely softened the ride. When I ordered a custom steel road bike, spec 25 mm Conti GP 4 season tires. Some how they got 23 mm tires, which I didn't initially notice. The ride was quite nice, ran them at 95-100 psi. Hit some wire that ruined the rear tire. Put on a 25 mm tire, and ran with 23 in front and 25 in the rear. The ride quality improved, soon replaced the front with 25 mm. Had a nice ride with 23 mm, 25 is even better. Keep tire pressure around 95 psi. So 23/25 pressure and construction was very similar. Don't race, but didn't really notice any true speed difference between the two sizes. Did get much better wear from the 25. Mm tire. IMHO - if they fit, wear them.

bikepro

I read Velonews articles that said pretty much the same thing, but their test protocols weren't as rigorous as these. I have a 25 on the rear for the improved comfort. Unfortunately a 25 won't fit the front.

jimmuller 

Yeah, but...but...but...

If all of your riding is at a constant speed over a particular road surface then maybe the rolling resistance matters. However I never ride a constant speed. Conditions make me always accelerating or decelerating. Deceleration doesn't depend much on total tire and rim weight simply because brakes are good enough to stop the bike anyway. However my engine isn't as good at acceleration. The lighter the wheel and rim combination the faster it spins up, and that translates to reaching whatever speed I want faster. It certainly feels faster to me.

gregf83 

It's incomplete. They indicate about 2.5W @ 36kph savings going to 25mm but don't mention how much power is wasted due to extra aero drag.

In any case, 2.5W is in the noise so ride whatever tires you like

gregf83 

The amount of energy required to spin up a wheel, heavy or light, is very small. If you don't believe me put your bike on a stand and hook a spoke with your finger. Not a lot of power spent spinning a tire and rim up to 40kph. I can pretty much guarantee you wouldn't be able to measure a difference in acceleration between a 23 and 25mm tire.

Carbonfiberboy 

At ~160 lbs. I rode 23mm tires at 140 lbs. for years, though on a carbon frame. I've lost 10 lbs. and now ride them at 120 lbs. Narrow and hard is definitely faster. There is no tire testing that shows the opposite, though on very rough roads or road with giant chip seal, softer tires are faster no matter the width. That said, it is true that 25mm tires inflated to the same pressure as 23mm tires will have lower resistance. Except that no one does that.

I run 25mm tires on our tandem, which at 340 lbs. all up, needs them.

This store just wants you to hop on the latest "it's faster" bandwagon and sell you more tires. I got the email, too.

DnvrFox

I ride my 25's at 120/120 lbs. Have since I got my Lemond BA in 1999.

kingfishr

I weight 150 and am running 25 front and 28 back at 80 psi on both my CF and steel bikes and can't notice any difference in my speed, strava times, or watts produced and generally average around 20mph solo on varying terrain. But on the rough country roads we frequently cover on our three weekly club rides they are noticably more comfortable. The optimal width and inflation of a tire is dependent on the road surface. On a velodrome 19mm at 120psi might be right, and for Paris-Roubaix pros ride 28 or wider at much lower psi.
At least for me going to 28 back ended my search for a new saddle...

OldsCOOL

Weight is the main reason why I ride 23's. I built (and still building) a light/quick bike and there is nothing going on it that is heavier. It really is that simple.

I do not ride longer distances than 70mi and often do 60. Comfort isnt an issue.

Currently and on their last season of 3, Michelin Krylions have done the job. I chose them over the heavy 25's they replaced and have enjoyed them. This tire was tested to have a top 3 rating in rolling resistance.

irwin7638

I went from 23's to 25's on my road bike years ago to eliminate all the stress and activity from the chipseal in Michigan. The larger tires will roll faster over an irregular surface (like anything but tracks). There's more to think about also. Jan Heine from Bicycle Quarterly has written a number of articles and blog posts on the subject. The supple quality of the sidewalls also have a lot to do with it. They have done some extensive research to determine the "best" and most efficient profile and found that wider is generally better within a range. For instance, on rough tarmac 28mm might be a better choice than 23. On my touring bike, I found that 50mm Big Ben's are faster than 38mm Dureme, but neither obviously will be faster than 23's. They found that pressure is an issue and that a tire is most efficient if compressed 15%. All this led them to postulate that the front tire should be carrying less pressure since there was less weight on the front axle. There formula is 60% rear 40% front, and there are downloadable calculators available for this and I have trouble trusting the numbers I see, but I have been running 10-15lbs less in the front and am a happy camper.

Marc