Gear Ratio for 37s

[OL Sarge]

Hey All,
I am planning on running 37s on my JKU. I currently have 35s with 3.73 gears.
Should I run 4.10/4.56/4.88 with 37s. I dont do lot of crawling trails mostly

 

[swampdog]

4.88 or 5.13. I would not do 4.56 with 37s.

 

[BlueBox]

What trans?

4.88 for automatic or manual

You can squeak 5.13 on a manual if you don't mind revving a little high on the highway

Edit: also what motor? 3.6 see above

 

[MedixJK]

Depending on which motor/trans, id do 4.88 or 5.13

 

[hinrichs]

I have a 2015 4dr Auto 3.6L and I went 5.13 for my 37s....very happy :thumb:

 

[Exodus 4x4]

5.13......

 

[NevadaZielmeister]

I went 5.38 and am very happy given the weight of my vehicle, but live next to trails, so never commute with my 37's.

 

[utiadam]

I'm running 5.13 in a manual trans with the 3.6 engine on 37s. It's been great.

 

[DWiggles]

I'm running 5.13 in a manual trans with the 3.6 engine on 37s. It's been great.
View attachment 207592
View attachment 207593

Exactly. :yup:

Only its 40° warmer here

 

[NecessaryEvil]

I just installed 5.13s with 37s and am happy. I got about 14mpg on my recent trip to Arizona from Illinois. I had head winds to and from. Go figure the only time I drive back east I get westerly winds! Lol

 

[BitBucket]

5.13s with 37s, 3.6 liter, auto trans. Works great for me!

 

[tgoss]

Currently have 5.38's and I'm going to swap in my 5.13's asap. They are just a little too deep to commute on for my taste.

 

[JJK]

Another vote for 5.13's

 

[OL Sarge]

Thanks guys
I have auto with the 3.6 and its my DD

 

[Hammmerhead]

I'm running 5.13 in a manual trans with the 3.6 engine on 37s. It's been great.
View attachment 207592
View attachment 207593

I would have thought there would be more than 500 RPM difference from 65 to 85 MPH. Is this because of it being a manual?

 

[JohnnyWest]

We've got 5.38's in our 3.8L and 5.13's in our 3.6L. Both JKUs on 37" Cooper STT Pros. Happy with both set ups, though the 3.8 is definitely slower. Here are charts for both the 3.8 and the 3.6 that might help.

 

[spencerd45]

Another vote for 5.13's

Agreed 100%! I drove a friends with 37's and 5.13's in G2 axles. Power was incredible compared to my 35's with stock gearing

 

[Ddays]

5:13's all day. Ran 4:88's & they were ok but with new axle 5:13's proved to be the sweet spot for me.

 

[Ddays]

Wait...what axle are you running? If it's a D30 the 5:13 pinion will be awfully small. On a D44 you'll be ok

 

[Mike_JK_Houston_711]

I have 4.88 on my 37s and they work amazingly. 4.88 or 5.13...no lower than the two.