A good place to start is measure the air gap you have now between the edge of your drive belt and the side of your rear tire (guessing, 150/something-16). The other limiting factor will be the same gap between the edge of the tire and the swing arm on the opposite side from the drive belt. Next comes the width of the rim. All three need to be checked and one will become the deciding factor. On my previous road star warrior I bumped up the rear tire from the stock 200 to a 260 but that needed some major modifications to the right hand side of the swing arm and I also had to have the rear wheel width increased from 6 inches to 8-1/2 inches. Tire life improved significantly, handling changed slightly but I adapted to it after a 20 minute "get aquainted" ride. After that I had the chicken stripes down to less than 1/4" and was back to scraping in the turns. And then there was the "coolness factor" which can't be described with words. The 260 came within 1/8 of an inch of the drive belt.
This picture shows the disfigured right hand side swing arm to make room for the 260 fatty:
Last edited by stratowart; 07-14-2011 at 01:08 PM.