Rim question

[250xridamatt]

I am looking for new rear rims after trashing my beadlocks thanks to loose lugnuts. What would be the difference of running 9x9's or 8x8's with my 18" klaws. I know I have 8" now, but what would happen if I ran 9"?

[chapmanmd]

Less sidewall flex which isnt necessarily a good thing for MX.