Any problems running 35’s with 4.88’s

BFHolt

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Oct 1, 2021
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Location
Birmingham
I put 2.5 full suspension lift and 35’s on my 2016 Rubicon. I was immediately unhappy with the power. I am Upgrading to 4.88. The shop started out talking about 4.56 but when I suggested I might eventually got to 37’s, we settled on 4.88. Reality is setting in and I don’t think I’ll likely ever go to 37’s. Is it a problem to run 4.88 with 35’s?

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I had 35 on my 08 JK manual with 4.88, ran them for 3-4 years. Off road they were great on road high RPM. Past Summer went and upgraded to 37 and now this is the sweet spot. My gas mileage improved from 13 MPG to 15.5 MPG city and getting close to 17 highway. If you have the 3.6 and staying with 35 the 4.56 may be better for you.
 
I'm running 4.56 with 35's and like it. I average about 17 mpg city. At 70mph the tachometer is reading about 2800 rpm's. My Jeep was not stock when I bought it so I have no idea what the rpm's would be at that speed if it were stock.
 
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Here's the gearing chart for the 3.6 manual and auto trans. The goal is to put your JK in the sweet spot (green). As you can see with the suto trans, your JK will run at 2576 RPM @ 70mph with the 37" tires, and 2723 RPM with 35s. Both in the high RPM range for a daily driver.
The 35" and a 4.56 gear puts you right where you want to be.

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I know it's apples and oranges, but I have a 2007 H3 with 4.56 gears and a detroit locker in the rear.
I really like the Hummer for a winter/trail beater.
It has a lot of miles, and it is a Michigan vehicle, so restoration or accessorizing doesn't make sense.