Gear Ratio for 37s

O

OL Sarge

-

• Jun 10, 2016

• #1

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

New member

• Jun 10, 2016

• #2

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

 

BlueBox

New member

• Jun 10, 2016

• #3

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

-

• Jun 10, 2016

• #4

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

 

hinrichs

Caught the Bug

• Jun 10, 2016

• #5

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

 

Exodus 4x4

New member

• Jun 10, 2016

• #6

5.13......

 

NevadaZielmeister

Caught the Bug

• Jun 10, 2016

• #7

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

LOSER

• Jun 10, 2016

• #8

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

 

DWiggles

Caught the Bug

• Jun 10, 2016

• #9

utiadam said:

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

Click to expand...

Exactly. :yup:

Only its 40° warmer here

 

NecessaryEvil

Caught the Bug

• Jun 10, 2016

• #10

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

Member

• Jun 10, 2016

• #11

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

 

tgoss

New member

• Jun 10, 2016

• #12

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.

 

J

JJK

Member

• Jun 10, 2016

• #13

Another vote for 5.13's

 

O

OL Sarge

-

• Jun 10, 2016

• #14

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

 

Hammmerhead

Member

• Jun 10, 2016

• #15

utiadam said:

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

Click to expand...

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

New member

• Jun 10, 2016

• #16

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.

 

Last edited: Jun 10, 2016

spencerd45

New member

• Jun 12, 2016

• #17

JJK said:

Another vote for 5.13's

Click to expand...

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

Hooked

• Jun 13, 2016

• #18

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

Hooked

• Jun 13, 2016

• #19

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

New member

• Jun 13, 2016

• #20

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