So I recently re-geared from 3.21 to 4.56 for the 35” tires I have on my 2015 JK 2 door.

PRevious owner had the 3.21 gears with 35s and it was a dog. Horrible acceleration and everything so after buying it I chose to re-gear after hearing and reading so much about the night & day difference it will be, how great the acceleration would be, barely have to touch the pedal from a stop to get going, etc.

So I got it re-geared last week and it doesn’t really feel much different to me? I was expecting a night & day difference from the time I left the shop but after driving the acceleration still doesn’t seem much different. I was advised of the break-in period and to take it easy, no off roading, no pushing the throttle too hard for 500 miles, etc. but shouldn’t it still feel different immediately? Or does it take a little bit of time? maybe my expectations were too high but I thought the difference would be obvious and it isn’t yet. Is this normal?

Also, I did change the gear ratio & tire size using the JScan app. Did I maybe do this wrong? I followed the steps correctly as I read them.

Any input from your experience would be appreciated!

 

It's all about personal opinion and expectation, but yeah, I think people tend to over-exaggerate at times. Regearing brings you back to a more proper power profile, but in no way is it a cheap alternative to swapping in a Hemi. The break-In period has to do with the physical health of the gears, it will have no affect on the power you feel. (don't cook the gears and make the metal brittle or whatever engineering term is correct to use. Heat/Cool cycles instead...) You can mess around with plugging in other gear ratios and tire sizes through the j-scan, but don't expect that to make a difference other than maybe slight changes in at what rpm's an auto will shift.

 

It is definitely not adding extra horsepower, you're just bringing the jeep back to more factory shift points. You moved 3 gear sets.....that was a big difference, but if you're expecting 100 extra HP, then no, I can see your disappointment. One spot you should notice a big difference is re-gaining your top gear. Do you have an auto or a manual? With an auto it's more noticeable cuz you're not downshifting near as much at the top end.

 

You are going to notice it more off road and on the highway where you will hold your speed and climb better over hills and overpasses. It does not act like a turbo adding HP.