well i am after the best fuel mileage. right now i have 285/75/16 tires w/4.10 gears.(tires came on the truck) is it better to get a little taller tire to help your gear ratio & achieve better mpg, or does it hurt you. i would not get an extreme tire but would like to know how big of a tire starts to kill the mpg.
thanks guys.
p.s. right now other than tires the truck is a straight up stock. 130k

 

I am running 295/70/16 with my truck with a smarty and am getting 20mpg. I think you should be ok with up to 315 with no problem.

 

The biggest factor in mileage is wind resistance, not rpm although that is still important. If you can stand it, you would be best off to run something like a 235/85/16 and slow down to a max of 60mph. 315's would kill your mileage because they raise your truck a little and are much wider. They also have significantly more rotational inertia.

If mileage were your only concern, we would all be running very small, narrow tires with really numerically low rear end ratios.

 

I agree with the skinny tires. Big, fat tires are like a barn door going down the road.
Don

 

I have always heard a tall, skinny tire will net the best mpg. But no test to prove that.
Cory

 

well thanks guys. i may try to have the uncoolest truck in town but i am going to get the tallest skinny tires i can with a stock setup.