I have heard of and seen some people with vintage bikes at the track that run a reverse front tire on their rear rim becaue they can't find tires in the size needed. Does this still work with newer tires that have plies laid in directions that are not 90 degrees? Of course this is dry weather only. I found this quote on a Norton message board.
"I've had to fit front tires onto narrow rear rims on my road race AJS. I was assured by various tire reps (people who, unlike me, actually *really* know something about tires!) at the track that this was safe. Just reverse the direction of rotation if the tire is a bias ply. On a true radial tire the arrow won't matter, either direction works."
i have heard of many people running race slicks either direction, as well as dunlop d208's backwards, apprantly they have better rain characteristics that way... im sure this is useless to you but its all i know :P
this is my...boomstick!
Tread pattern is an issue in the wet and that is the main reason a tire is directional or not. A radial carcass won't have a right way and a wrong way to rotate.
BTW, a modern tire is one with it's plies laid 90* to the bead. That's what "radial" means. Bias ply tires have the plies laid at 30 or 50 or whatever degrees, crossing each other.