What will 12.5 inch wide tires do to the handling on a 400EX with the stock 9 inch wide rims?

 

Aren't stock rims only 8" wide? Take a look it is stamped on the inside of the rim. I always switch to ITP 9X9 rims to get a little extra width. It costs extra money, but out here in dune country you need a second set for your sand tires anyway. The widest I have run is 11" wide Holeshots, with no problems.

 

i have seen a 300ex with 22x12.5x9 super-swampers on stock rims.