I was doing my gas mileage calculations and I remember reading a post on lifted jeeps and actually going 1.1 or 1.2 miles per mile that the trip gauge says it is going. Onyone have a definite on this? I have a 1990 4in with 31's. thanks

 

yes, you have to get the right gear for your speedo

 

Yes, you actually do, go it gets off..which in return can make your mpg "look worse.

 

A tire that is 10% larger than stock will drop the speed and odometer readings by 10%.

 

A lift won't affect speedometer readings but different tire size definitely will.

 

Jeep Speedometer Gear Chart

-Joe