Heavy rims dont matter that much on a chopper, i think i would even enjoy that gyro effect when hammocking down the road!irk miller said:The problem with Kawi mags is they weigh 312 pounds each. Im'a look anyway. And since you guys all hate Comstars, maybe I really should use them. As far as thumpers, I don't think this is the frame for a thumper. It's a CB750 frame, which means the cradle is pretty big. Most thumper motors will look like a Z50 in this frame.