I'm in the process of adapting street wheels to my dual sport (1994 Yamaha XT600E). The bike is always used on the street except for the occasional trip to Colorado. I want the cast wheel look and the convenience of easily swapping between knobbies and street tires. The front wheel is a FZR400, it appears that it won't be much of problem to adapt. I'm using the Suzuki GS500E rear wheel. Unlike most swaps, I have plenty of room, machining the sprocket hub won't be necessary.
Here's my question: The disc on the GS500 wheel is about 3/4" larger in diameter than the stock Yamaha disc. I can make a new mounting bracket and all that, but my concern is that the larger disc will create too much braking force on the rear and cause a lockup at the wrong time. Is this small difference in diameter something to worry about? What have been other's experience when changing to a larger disc on the rear? I can't turn down the disc on a lathe as then there would not be enough area for the pad to sweep the rotor. Any feedback?