Hi there will a set of 26" mudlites fit on stock 2004 grizzly Rims

 

ttt

 

Yes they will. 26 x 10 x 12 (front) and 26 x 12 x 12 (rear) will give you the profile closest to your stock tire size (but they will be wider). However if you mount them on ITP C-Series wheels instead of your stockers, your quad will have a wider stance and will be more stable in return, plus having the extra wheels gives you the ability to easily swap tires for different conditions. Note however that with this setup you will get muddier because the tires will stick out farther than your fenders, so if you want to compensate for that you will have to add "over fenders"...