140 rear tyre
A guy I respect quite well advised me that sometimes if you put a tyre too large on the back, it makes the bike harder to turn. He put a larger tyre on his Tenere 660(?) and went back to the smaller stock size tyre. His other bike is a KTM400 I think. But he can ride...really ride....makes me look like I'm stuck in first gear.
Having said that I have run a K60 and a E09Dakar in 140 on my F650, and I think it's fine...but I probably wouldn't really know until I tried a smaller tyre again.
"That guy with the tag on the back of his jacket, he's got a different chip in his head..."