My KTM 690 enduro came with a 140/80/18 rear tire and I am having a hell of a time finding a good replacement in that size. I have been through 3 sets of tires already, pirelli mt21 (lasted a while but traction was less than satisfying) interco teraflex size 150/90 (rubbed the gas tank and was squirrely in the corners although straight line traction was A+) and a pirelli scorpion pro (traction was fair but it only lasted 400-500 miles and was f-ing expensive)

The bike is ridden 90% offroad and the tire need not be DOT approved but it seems like my options open up greatly if I go down to a 120/100/18 or there are even a few 130/90/18's (motoz x-circuit) that I am considering. The rear wheel is 2.5 inches wide as opposed to a more typical 2.15 that I had on my 250's and 450's. Is there any real concern running a narrower tire on this wheel? Height would be about the same either way.

Anybody run a 2.5" rear wheel on their dual sport/ dirt bike? If so, what size tire are you running?