I got some closeout michelin pro races online really cheap as the pro2s are replacing them. They were mislabeled as 700x23s on the page and were actually the 20mm ones when I opened the box. (The actual tire box says 23 x 622 even though the embossing on the tire reads 20 x 622. I’m not faulting the website.)
I’ve only got one bike and one set of wheels. This is going to be my training/group riding/racing tire. (Hint: I’m on a budget and price is very important.) I really liked my last set of pro races. They lasted forever and seemed fast. The 20s actually fit my rim profile perfectly (they make 23s look huge!), so I suppose there will be an aero advantage, as well as the likely rolling one.
Will I destroy my behind? I took them for a quick spin and actually couldn’t feel any difference. I suppose I could only inflate them to say 100 psi for training if it helps. That’s still well within the spec, and I don’t care if they wear faster for the price.
I’ve got a custom bike with a VERY close rear-wheel cutout, so I have to train on 700x20’s. I’ve been using Continental GP3000 for several years without noticing any different ride than my other bike with 23’s. However, I’ve gone down when crossing sand that had washed over the road with the 20’s…that was no fun…they’ll cut through sand/dirt/mud noticeably quicker than a bigger tire and get squirrely, but on a normal surface, no difference.
I weigh about 150-155 and when I switch from 700x23’s to 700x20 I need to pump up the pressure by 10 to 25 PSI to avoid pinch flats. It wasn’t worth the harsher ride for me. Plus when you do get a flat, takes that much longer to inflate on the road, if it’s all possible to get close to the desired pressure. YMMV.
I’ve trained on 20’s and 23’s. The only difference between the 2 sizes will be your confidence in cornering. I wouldn’t worry about all that aero BS as the difference is going to be so small it won’t be noticable. You’ll get the same training effects out of a 20 that you would a 23 and anyone that says different is probably just pushing for a little more of your money.
This year I got a deal on a set of Conti GP3000’s in 20…I put them on my “training wheels”. The only noticeable difference I found is that on rough (chip seal) pavement they are a bit harsher and don’t seem to roll over those imperfections as easily. I’m not sure if this is effecting the rolling resistance at all or just effecting my “saddle comfort”…
I ride a 20 on the front and 23 on the back for training and for races. I decided that I might as well train on the same size tires as I race, so that I will be prepared for the difference in handling. The 20s are slightly harsher in the front, but that’s mostly because it’s a Conti 3000 as opposed to my standard Michelin Carbon. I have about 2500 miles on the front now and just picked up my first glass slice last Saturday… I still don’t understand how people get pinch flats all the time. In 10+ years of riding fairly high mileage in the midwest and now Floriduh, I have had exactly 1 pinch flat. Well, since the rim folded in on itself I don’t know that calling it a pinch flat is even right. BTW-I weigh 160lb.
Anyway, I found the 700x20 Pros to be very comfortable, way more than the 700x23 contis. Try it and see, worst case is you can race it like I do with 20s in the front. But purple…whew…not sure I could ride on that.
I similarly ride a 20 on the front and 23 on the rear. I find I need a 23 on the rear to hold corners when I bank heavily, but a 20 on the front noticeably reduces rolling resistance, should improve aerodynamics and I can’t feel any differance in either handling or braking.
BTW-I weigh 160lb.