I,m using a Dunlop K505 140/70-17 on my K8 with no clearance or performance problems but I dont like it because , even with 2" shorter shocks it just doesn't fill up the wheel well . I think I would prefer an 80 or 90 series over this 70 low profile. But it does stick nice! I'm looking for something taller, think I may be able to fit a 150 in there, with the 140 I have 3/4 " to the swingarm, but chain and brake stay are closer
Good Luck,
George