You can run up to a 200 tire on the stock wheel. Same holds true for both the 650 and 100; can't say for sure on other models! I just put a 200 on my 650 and I can't tell any difference in performance or speedometer change. My dealer told me the differences would be so small that they really can't be detected.
I changed My rims and tire I was able to get 200 to fit without changing the fender or putting a wide tire kit in. I think besides looking great I have better traction and no i havnt realy noticed the speed chang. Go Big it Just is BETTER
If you use a 200 width to not see a speed difference you should be using between a 50 and 55 aspect ratio. Otherwise the circumference will be larger and you will be traveling faster at a given indicated speed.