When it had Discount tire fix 2 leaks, they recommened it go to a different size of tire since the 255/70/R18 is hard to find. They recommened 275/65/R18 which is the same size (only 0.01" larger in diameter) and only 0.8" wider. Discount said that size are more commonly used as LT's on F250's & F350's trucks.

George suggested 265/70/R18 which are 0.55" larger in diameter and 0.4" wider, however when my speedomter says 70MPH, I'd be going about 71.2.
Anybody using any tire sizes other than stock? I'm not looking for something real wide or tall. I want to keep the ride comfortable, not screw up the speedomter too bad, and no clearance issues.