hey I have a '98 ext. z71 was wondering what the offset and back space specs were on the stock rim, cause I'm getting a lil' bit of rubbing on the back inside the fender will, from the inside of the tire, anywayz, was debating if it would be better to get wheel spacers or just bye new rims, but if I want to rims, need to know the specs so I can make sure that i have room, plus i'm about to go up a size on my tire, prob. to 275/75 maybe 285/75 thanks