OlderMan53
New member
So i went and put 35/12.5/17s on the jeep and immediately lost 2 mpg. Getting ready to learn about gearing but if i can get suggestions that would be great, it's my daily driver and mostly highway driving to and from work.
35s
- Thread starter OlderMan53
- Start date
Unfortunately, bigger tires mean loss of power and fuel economy. Mud terrains will do worse than all terrains. That said, did you make sure to recalibrate your speedometer? If not, start there. If so, re-gearing will help restore power and improve what you’re seeing but you will still have less mpg.
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OlderMan53
New member
Power would be worth it. I piss off a lot of people going to work.
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bobfriesenhahn
Hooked
If I were to do it again, I might select a tire narrower than 12.5". An inch narrower is surely good for at least one MPG since the tire is more within the fenders, has less resistance to wind, and is lighter so it takes less power to speed up (and is easier to stop).
GP NOIR
Hooked
If you aren’t off-roading, the most practical choice is to return to a smaller tire.
What gears does your Jeep have now?
OlderMan53
New member
I have absolutely no idea. Jeep looks way too cool to turn back now.
OverlanderJK
Resident Smartass
Did you recalibrate your speedometer after the tire change?
juanbenae
New member
It's not just about the speedo recalibration, if you used JSCAN it will also sort the shift points in an auto trans. I use it 2x a year, in the winter reprogram for my smaller snow tires, and again in the spring for my 35's. When I went to 4.88s it would not even move until I reprogramed for the gear change.