On Tuesday, April 6, 2021 at 1:10:55 PM UTC-4, Frank Krygowski wrote:
On 4/6/2021 12:05 PM, Mark cleary wrote:
I notice that the Conti GP 5000 I have and even the old GP II 4's, have a direction of rotation on the sidewall. Now mind you I so far have put the tires with the proper rotational direction, but what happens if you don't.. My guess is if you put them on the opposite way then does the bike go backwards when I start pedaling? Do the tires wear out different, or possible be off balance. But seriously what is the catch?
Deacon Mark
Schwalbe says that for road tires, it's essentially cosmetic.
From https://www.schwalbe.com/en/profil
"Why are so many treads direction dependant? [sic]
"In the case of a road tire the rolling direction is mainly important
for aesthetic considerations. Tires marked with arrows simply look more
dynamic..
"Off road, the rolling direction is far more important, as the tread
ensures optimumconnection between the tire and the ground. The rear
wheel transmits the driving force and the front wheel transmits the
braking and steering forces. Driving and braking forces operate in
different directions. That is why certain tires are fitted in opposite
rotating directions when used as front and rear tires.
"There are also treads without a specified rotating direction."
--
- Frank Krygowski
Even off-road directional rotation doesn't make much difference - you have to really push the limits of the tire in order to realize a difference, which is generally much more aggressive than any non-racer would attempt. I remember an article in velonews probably 20 years ago where an engineer for Specialized was interviewed on this very subject. He said choosing the right tread for the terrain is vastly more important than being concerned about the direction of the tread. He even gave the idea of front/rear specific off-road designs a big "meh".