Join Date: Mar 2002
Location: California Central Coast
The stock 170 rear is the widest tire that can be mounted on the stock 5.0 rim. It may be possible to mount the VFR800's 5.5 and a 180, but I don't know whether the clearance, offset, and bolt pattern are compatible.
And a wider tire won't improve cornering. In fact, in may slow turn-in. Some literbike riders are downsizing from a 190 to a 180 rear to improve steering.