Gas Mileage

[Sierra5.3]

I've always wondered if you could Run bigger tires and still retain the mpg you get with stock size tires. Thanks

[Shaners]

There's no doubt you lose a little mpg even if you reprogram your tranny.

 

You'll have greater rollling resistance, and a slightly different gear ratio.

 

I don't think it would be much, but you'll probably lose 1/2 mpg.

 

(alot depends on the tire too...  some tires require more HP to turn than others... )