I currently have a 2005 4x4 with the AS 2.5" leveling kit. I am thinking of going with a 315/70-17 tire on a set of 17x8.5" wheels with 5.5" backspacing. Do you think I will get any rubbing with this setup? Also, will I have a big power loss? I have a 3.73 gear.

 

thats a 34.5" tire- assuming you are right on 5.5" BS [which i believe is same as stock] you should be pretty decent- you may experience some minor rubbing on your control arms at full crank left right, and turning while in reverse... you will notice a bit of low end, acceleration loss with the larger tire, but nothing too drastic. if you've got an XCal II or an Edge Tuner either will make up that loss plus some on the performance.

 

Most people running that size tire (essentially 35x12.50's) are using OEM wheels which are only 7.5 inches wide with 5.5 inches of backspacing. You will probably have to do some trimming.