Hello

can someone tell me why all mx quads are running 8" or 9" rear rims?
What is the difference between running an 9" rim with 20" tires, and running a 10" rim with 20" tires.

Is it just because of the larger sidewall?

I have 2 sets of rims, one with 9" at the rear, and one set which has 10" front and rear rims.
So i like to know which one i should put the mx tires on

most mx guys runs 18 inch tires on a 8 inch rim, the side wall will help, but i believe the biggest factor is tire choice, more 18 inch tires are available for a 8 inch rim, as for 9 inch, you can run them, you will have a little shorter side wall, and might bend your rims easier, i dont know if you will find any 18 inch tires for a 10 inch rim, most people with 10 inch rims run flat track, they want a low profile tire to help slide and such.

the 18 by nine works well with lower powered macnines. your best bet is to get a set of eights an some 18s. they seem to corner much better and are alot easier to correct your turns with. i also bought a set of 19,10,10 holeshots to try out on the more loose tracks and they work awesome for bieng on a ten inch rim.

well, it's not really for competition, just some fields and stuff.
Going to the track sometimes.

i always used 20" tires on 9" rims for the stuff i do, so i guess 20" on 10" rims will work just fine ? :)