It's the width of the rim. The hub width is somwhat irrelevant since the real limiting factor is the width of the swingarm. By the time you get a 180 tire on a 5.5" rim, you've got a bigger package than anything with a shaft in the 80's had. Most bikes in the 80's ran 3.5" rims on the rear with skinny tires. The VMax from '85 may be an exception but I doubt it. Wide rims were appearing on sport bikes in 1987 but I don't recall a shafty with wide rims until later.Superfly said:Is the 5.5" at the tire, or is that at the hub?