I am running 31x11.50 with 3.73 gears. How much would changing to 4.10 gears and going to 35x12.50 change my mpg? Would it be better to keep the 3.73 gears and run 33x12.50 or do the gear swap and bump up to the 35's?

 

if you're going to regear, you really should go no less than 4.88's with 35" tires. that'll bring you back to about stock performance. if you want more pep, 5.13 is what you'd want but, you should know that on the highway, your rpm's will be a bit higher. if you're just going to 33's, your 3.73's will be just fine. hell, i would even run 35's with 3.73's and have in the past. yes, you will feel power loss but it's tollerable.

 

I've got 5:13 and a auto with 35" tires gets around 15 MPG on average its better now with this than it was with stock tires and gears MPG little lower now but I can live with it. If u put 3:73 in u can get by but u will not have much performance and I think your MPG will really suck with 35" tires

 

nah, i've done it for about a year and i actually got decent mpg. heck, i even ran 37 falken at's with 3.73 for about 4 months and still managed to get about 14 mpg. a lot of mpg depends on the tires you are running and how much rolling resistance you have.

 

If you're sticking with the stock gears for a while, you can get a Superchips Flashpaq to help put a little more "oomph" back into the Jeep when you get the bigger rubber. Doesn't help with the MPG much, but at least it will help with the driveability a bit.

 

Was nemo a Auto or 6spd? Just curious on how it ran with 35's.

 

It won't tare up the tranny running 35's with 3.73? The service guy at the dealership said never go over 33's unless I regear atleast a 4.10.

 

^^^^


I have been running 33x12.50's with 3:73 for 3 years and have not torn up my rear end or clutch/manual tranny. I know a few guys on here that run 35's, 3:73 and auto tranny with no issues and few run 3:21's with 35's.

 

Yes, it will put more strain on the drivetrain. Enough to cause issues? Maybe. Enough to have a dealership service department want to deny warranty? Depends on the dealership, but they have denied for less cause.

There was a thread a while back from a guy that went in to get his tranny replaced. The dealership asked if he had re-geared for his 35" tires. He said yes. They approved the repair. If he had been on stock gears, they would have denied. (you can also find posts from people stating the exact opposite, so take it for what it is worth...)

 

I guess the best move is call the dealership and ask what they will warranty before making the change