Sizes are 180/55zr17 rear and 120/70zr17 front.

Ive got the standard Bridgestone BT014's on my K5 GSXR600 at the moment mate and im happy to stay with these really.

Its only the rear thats ready but id feel better replacing both.

I was also wondering today whether i could fit a 190 rear, but i assume the thou has a wider wheel to accomodate it?

Cheers.