1990 Suzuki LT230E QuadRunner
 

I took the old 22" rear tires off and put some 20" rear tires on. This obviously changed my gear ratio and speed from about 55mph stock to 50mph now. I'd like to get that speed back, and it looks I can do so by putting on a 13T front and 40T rear. My question is, is it safe to put a 13T on the front, is there any grinding involved?