I am trying to figure out whether to go 700x20 or 700x23 on my Renn disc/ tripoke race wheels - right now I have 700x20 GP 3000s - I’ve read that the 23s may actually have lower rolling resistance, are more comfortable and alot more pro cyclists use this size than the 20s - (may be BS) I am curious what people here actually run on race day. Please post your weight as well.
700x23 Conti Supersonics - 170 pounds.
Conti Attack / Force combo. 22mm front / 23 rear. 170.
23s at 100 psi, and no higher. I weigh 152.
Conti GP3000, 700X23. 170 lbs.
Brett
bmacfarquhar,
I’m presuming that the racing you’re asking about is triathlon racing, which is generally more like time trialing than pack riding/drafting as road racing is.
I’m surprised that with all the expense and effort cyclists/triathletes put forth in an effort to obtain aerodynamic benefits and all the “aero” experts on this forum that no one is chiming in to point out that to achieve/preserve maximum aerodynamic benefit from your wheel, your tire width should be no wider than your rim width. Our recognized expert, John Cobb discovered this in his early wind tunnel research. Therefore if your wheel rim is 19 mm wide, a 23 mm wide tire is compromising the aerodynamic benefits of your wheels. A 25 mm wide tire would be even worse.
This deterioration of performance had something to do with the additional turbulence created as the airflow wrapped around the tire and then was disrupted by the unevenness from the tire’s widest point to the rim’s widest point. As the surface of the tire/rim combination became a more continuous straight line, the maximum aerodynamic benefit was achieved.
All this being said, unless the road is truly terrible, I ride 20 mm tires. Usually Continental Grand Prix Supersonics. If the road is marginal, I will use Grand Prix 3000’s. If the road is so bad that I’m worried about pinch flatting with the Grand Prix 3000’s, then I find somewhere else to race. But I’m time trialing, not road racing where aerodynamics play less of a part. But I think I’d still be inclined to race on 20 mm wide tires. I’m 6’ 0’’ and 185-190 lbs.
I weigh around 170, depending on my last meal/binge drinking episode/bowel movement/anerexia battle.
Clinchers: mostly 23mm tires, whatever is free…or kenda’s 165 gram clincher (when i’m not worried about punctures), or whatever michelin tire i can find for less than 20 bucks (bought a whole bunch of high lights at 19 bucks each, and a pair of carbon comps for 20 each).
I have ridden some 19/20mm kenda’s before, they were wicked light, fit the rim well, and seemed to get the job done, but they felt weird so i have them hanging up now to be used when i run out of tires.
When it comes to tubulars, i’ll ride whatever i can get/use/borrow for free, this has included vittoria’s top o’ the line tubies (22 or 23 mm i think, at 120 psi on a set of rolf’s, they rode quit nicely but flatted very easily), conti grand prix (19 mm rear tire on a disc, gives me the willies when cornering hard), 22mm tufo (on zipp 38mm carbons at 115 psi, they didn’t slow me down any).
I prefer a wider tire for comfort and traction reasons. For most triathletes, while traction is a moot point, you will benefit more from the extra comfort alotted by a wider tire than you could possibly gain from a more “earo” narrow tore.
conti compititions 22mm recommended by john cobb on hed alps and hed 3 also blackwell disc wt-165
The difference in a 19mm rim and 23/25mm tire is not going to slow me down and probably not many people on this forum either. That being said when you buy tires it doesn’t cost any more to get the right size.
Well thanks for that - it seems alot more people go with 23s - I am around 170 too on race day (sometimes 160ish). I bought the 20s cause I thought what is the point in spending close to a grand on race wheels and than sticking unaero fat tires on them - however I have found that the 20s aren’t very comfortable esp on bad roads/ paths and really long rides. I may keep the 20s on my aero race wheels but start training on 23s. I ride a saber and thats a pretty soft bike so it shouldn’t be as bad as my aluminum training bike (not to get into the frame materials discussion - I have aluminum MTB and road, 853 steel road, and Ti tri and there is definitely a difference - the titanium is the most flexy - when I torque the rear wheel hard I can see the whole thing bending subsantialy esp on the trainer - 853 steel is really nice and may be growing on me more than Ti - think its my favorite and my 853 frame is same weight or lighter than my Ti frame - would like to see something like a P2k made out of 853, Alu is stiff and great for sprinting but does beat you up a bit more - esp cannondale MTB!. I think tire fatness and pressure makes a much bigger difference than frame material though)