Re-Gearing
- Thread starter Jeepin7
- Start date
MajD
New member
Your options with the carrier on the JLUR are 4.88s or 5.13's. 4.88's are totally fine to handle up to 37's and you will get 8th gear back (I did Yukons, they have a complete kit). If you think you're going to go larger then 37s you might want to look at 5.13s but you will lose some fuel economy for sure. Sorry if I'm assuming you are automatic trans
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WJCO
Meme King
315s on a JL Automatic with 4.10s is fine. I think regearing with that combo is unnecessary.
MajD
New member
I would agree with what he said, I kind of just jumped into the solution without reading your initial post. 315 70 R17's depending on manufacture are slightly larger than 34'' tires. The 4.10 gear ratio should be sufficient, they are just barely larger than the 33'' tires that come standard with the JLUR. I went with 37x12.5xR17's, also the KO2's and they are heavy enough to cause loss of 8th gear most of the time that a re-gear was needed. I would run it for awhile and see if it will hold 8th gear at highway speeds. You need to make a change to your vehicle display to show what gear you're in.
CalSgt
Hooked
Did you calibrate the PCM for the taller tires?
That will make a difference in how it drives.
I noticed a difference going to 4.88’s on my JLUR with 37’s and a decent amount of added weight.
honestly for the cost of a regear you’re not going to get enough out of it coming from the 4.10’s for that small of a tire change
That will make a difference in how it drives.
I noticed a difference going to 4.88’s on my JLUR with 37’s and a decent amount of added weight.
honestly for the cost of a regear you’re not going to get enough out of it coming from the 4.10’s for that small of a tire change
Yes. I did the PCM for big tires, and feels good. I agree with what I’m hearing. I do not think I’ll re-gear, unless I go bigger. Thanks all
2013rubirick
Hooked
I think if your staying with 315’s you shouldnt spend the money on re-gearing. I think it would be a waste for the added benefits. Now if you go up to a 37” tire you’ll definitely want to. 5.13’s and 37’s is the sweet spot for a jk.
I went to 37s and 4.88s not long ago. 4.56 would have been the numerical (rpm) equal to 4.10s and stock 33s. I was geting a lot of recommendations to go to 5.13s. But I like the engine loafing around at 65-70 mph.
From what i've read about those with 35s and stock 4.10s is that 8th gear is a rarely seen thing. I would think 4.56 would be the sweet spot for highway/street. Off-road won't change much, since the 4:1 transfer case is more of a mathmatical influence. My understanding is that you regear for street focus and that it has little impact on the off-road capability, unless you are going from really tall gears to really high multiplication gears.
From what i've read about those with 35s and stock 4.10s is that 8th gear is a rarely seen thing. I would think 4.56 would be the sweet spot for highway/street. Off-road won't change much, since the 4:1 transfer case is more of a mathmatical influence. My understanding is that you regear for street focus and that it has little impact on the off-road capability, unless you are going from really tall gears to really high multiplication gears.