Wide Rims
run a 100-90-10 on a wide rim on the rear (Yokahama pro-fire, and have another part worn to replace it, great tyres, but no longer available) great roadholding, ran a wide rim (original AF) on the back for years, no problems. tried one on the front , made the scooter steer like a wheelbarrow. then , when i fitted a hydraulic front disc, it wouldnt fit , the caliper was in the way. standard front with a michelin, and wide rear with a Yokahama, thats what ive got on at the minute. 100-90-10 up gears it a bit , so i"d say i"m running a 19 and a half front sprocket