Of course original tire sizes were 100 aspect ratio, meaning a 3.25-19 had a sidewall height basically 3.25" and a width at a matching 3.25". These tires fit and look better than the 100/90-19 to me, although not a big deal. 80 profile would be wrong for sure. Not sure what tire the stock 18" front Kawasaki like the Z1R used. Maybe a 3.50-18, just guessing, but maybe they had a wider wheel.
321,000 miles on KZ's that I can remember. Not going to see any more.
