my dad has an '04 silverado base model 2dw truck, 4.8 v8. it came with some ugly plain 16" wheels and 255/70/16 tires. the tire diameter is 28.8 (+ or - .1) on the stock 255/70/16's. He wants to put the 16" aluminum wheels or aluminum 17's on the truck. the tires on the 16" aluminums are 265/70/16 which measure out to be about 30", and the 17's with 265/70/17's measured out about 30.5" diameter. my question is; can i put either of these wheel/tire combos on this truck without reprogramming the computer for the difference in the tire diameter. i know these computers have tolerances, but I'm not sure on how big these tolerances are.

 

The 16's are close enough not to reprogram but the 17's are too big if he went with a 265/65/17 to be close enough not to have to reprogram.

Here's the site I used to figure it out.

http://www.miata.net/garage/tirecalc.html