what offset for rear rims

[Conner_S]

For XC? title pretty much says it..
thanks

[ccdhowell]

I use 9x8 wheels, 3 + 5. That's 3 inches backspacing and 5 inches frontspacing...and I race XC.

I have a set of 9x9 wheels that I'm gonna try, they are 3 + 6. Makes it about two inches wider without a new axle or spacers.