A friend of mine is going to change out his tires on his GMC and give me his old ones, which are still much newer than mine. They are Goodyear Wranglers size P265/70R17. I was just wondering if I would be able to swap these for my 255 Generals. I did not know if there would be any clearance issues or problems with going to a large size tire. Any info would be appreciated.

 

They will fit fine on yours, my brother runs the 265 size on his 06 XLT. They are only 10 millimeter wider than your stock tires, and therefore will not be that much taller at all based on the aspect ratio.

here is some helpful reading about tire sizing:
Tire Tech Information - A Guide to Tire Sizes

Tire Tech Information - Calculating Tire Dimensions