23mm vs 25mm tire for climbing
Moderator: robbosmans
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ever since i made the switch from 23mm to 25mm about a year ago, my flat & rolling speed have improved but climbing have suffered. not very sure if its the tires or the few kilos i've gained so would like to hear it from fellow climbers out there. i'll stick to 25mm's for my aero bike with aero wheelset but i have another climbing bike with climbing wheelset and would like to maximize its potentials
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Probably the kilos, but I have wondered what, if any, effect, a lower pressure mushier tire has on power transfer. What kind of pressures were you running in the 23mm vs. 25mm? I have noticed that with my 28mm tires at about 20psi less than I would run in a 23mm, you can really feel them squishing during hard standing climbing efforts when the bike sways side to side. There could be effects on the wheels ability to transmit force to the ground, but more so I am thinking of the deflection perhaps reducing the ability to put force into the pedal. Not saying anything for certain, but if you are someone who thinks that frame/crank/wheel flex can compromise power transfer then the same principals apply. Now having said all of that...there is a long and fairly recent thread on the frame stiffness altering power transfer question and the general conclusion was clear as mud, so good luck getting data on this one!
BTW, you said climbing speed suffered. How much did it suffer and how are you measuring it?
BTW, you said climbing speed suffered. How much did it suffer and how are you measuring it?
TheKaiser wrote:if you are someone who thinks that frame/crank/wheel flex can compromise power transfer then
... you are probably wrong
Tire pressure does affect rolling resistance, but wider tires are harder / resist compression better at identical pressure compared to narrower tires. Most or all of the reported lower rolling resistance of wider tires is due to this fact, and is lost when they are pumped to provide the same level of comfort as the narrower rubber.
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LOL, it is the kgs. 23mm to 25mm will make sod all difference in the real world. If you are noticing a difference in your climbing speed and you have gained weight, that is the reason.
If you went from a 23mm tire with very low rolling resistance to a 25mm tire with lousy rolling resistance, you might notice a difference. From memory its about 10w per tire from the lowest to the highest resistance reasonable race tire.
If the tires are the same brand and model they are probably very close in rolling resistnce. And in fact the 25mm might be lower than the 23. They often are. In that case it's the body weight, winter, bad day, etc.
If the tires are the same brand and model they are probably very close in rolling resistnce. And in fact the 25mm might be lower than the 23. They often are. In that case it's the body weight, winter, bad day, etc.
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The width of a nickel is 1.95 mm. Not likely such a trivial change would impact your speed. Most likely psychological , training related or even weather related.
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Colnago C-64 disc(ultegra) with Bora 35 wheels
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