im going through the same issue ( 09 850 xp ) , you can not put a 11" on the rear because of the rear swaybay. it will definetly hit on stock rims. either have to get aftermarket rims with offsets or go with a 27x9-14 all the way around. saw a xp at the dealer the other day with the gbc grim reapers in this size and it didnt look bad , . at least there wont be any power loss and those tires are pretty aggressive, better than our stock tires. thats the way ill be going , not spending another 300-350 in alum. rims just to bang them up. i think in 09 polaris screwed us knowing people usually upgrade the tires hoping you buy polaris rims, just my opinion

 

sorry , had a brainfart, thought u had a 09. 2010 should not have a problem, with existing tires (stock ) u have about 2.5"- 3" between tires edge and swaybar. 27x11-14 should fit.

 

Mud....Have an '09 (need to update my sig). I'm going to do the much spoken of sway bar modification (bending with straps). It's worked for lots of folks and I'll heard no ill reports back. Pretty simple and costs nothing to do.

I guess the 27" diameter is not a concern, but just wanted to check with folks. Going to search some more old posts and look around. Let you know if I find anything of value.

Check out that GBC line. There's some nice rubber for just over $100 each delivered.