Join Date: Nov 2009
Location: Lander, Wyoming
The 90mm width tire supposedly is suppose to have a 90% tall aspect ratio. So supposedly 81mm. And supposedly these are supposed to be Carcass measurements, not tread width to carcass measurement.
And when one looks in the books, the street tires differ from dirt tires when converted to simple Inches!
So like I said, 'approximates' or maybe better yet just a WAG!
Modify at "YOUR OWN RISK"!
Still riding my 1987 KL650-A1. 85,000+ miles & counting