effect of gas mileage

[T-MAC]

I drive a Jeep grand cherokee and was wondering how much of a difference tire size and tread type has on gas milage. Right now it has good year regatta 2's but I want to go with a little more agressive tire and a little larger.

[ogpog]

Whats your current tire size?

When i owned my Yj, and went from 29's, to 31's, then to 33's, i noticed the difference every time. My mileage went down the drain, so i regeared and was fine afterwards.

If you are just going two inches up or so in general tire diameter, i wouldnt really worry about it, especially with a grand cherokee (depending on the year). My yj had the same aerodynamic principles as a barn, so im sure that didnt help either.

So how big do you want to go?

[T-MAC]

Right now the tire size is 225/75-15, I was wanting to get a 2" lift and then 31x10.5. So not really too big a difference is it?

Would tread type affect mileage more than tire size? Because I am coming from pretty much a car tire.

[ogpog]

Originally posted by T-MAC
Right now the tire size is 225/75-15, I was wanting to get a 2" lift and then 31x10.5. So not really too big a difference is it?

Would tread type affect mileage more than tire size? Because I am coming from pretty much a car tire.

Well it can have its effects, thats for sure, but mainly when you are getting into very aggressive mud tires or boggers. What kind of 31 are you looking into? (BTW- Agressive tread will also cause slightly rougher and louder ride.)

If you slap on some 31 A/T or Mudders, i wouldnt worry about anything. You should be fine.

[T-MAC]

Nothing too agressive, just some light truck tires