Originally Posted by kkesp
I'm going to do a 18" rear conversion on my F800GS. You recommended a 2.5" width. I'm going to want to use a more road oriented tire 80% of the time. What would be the largest size I could use easily on the 2.5" rim. I was thinking a 3.5 would be better for me to running a 140/80. Thoughts?
the 2.5 width is optimal for mostly dirt oriented use,,with the proper tires it works finon the street,,if you're on the street more than the dirt we use a 3.5 x18..it's narrower than the 4.25 which can bend too easy sticking way out to the left/right of center-line...it works better on the the 140/70 lower profile...
remember the lower the profile the stiffer the tire will be on the road,,ie the sidewalls are almost vertical so they don't flex nor want to distort and tuck under the main thread.
herre's a tire fitment chart link to my website..peruse it and notice the correlation between aspect ratio and rim width