Originally Posted by
dsbrantjr
"They have opposite pointing arrows for <F-R>"
Well, that doesn't fit into either tread shape or internal construction categories. Esthetics?
Technically it's based on the tread shape since you want the front tire to have maximum traction when braking and the rear tire to have best traction for propulsion - therefore opposite directions. It makes a marginal difference in loose dirt/mud with tires that have substantial tread patterns - doubt it makes any difference with road tires or on pavement.