6 Speed and regear for 37s?

TerraJL

Member
I have the 6 speed manual in my 23 Rubicon. I'm sure this question is asked often, but with 37s and the 6 speed and 4.10 gearing, will I be ok to drive around like that? I already don't use 6th gear except MAYBE on the interstate above 70, which is rare.

TIA,

TerraJL
 

black pearl

Hooked
4:10 and 37s are fine if you’re always going downhill. I went to 5:13 but I also tow so I wanted a little more pep. I know most people are happy with 4:88s.
 

GP NOIR

Hooked
Crawl ratio for a JL with the manual is 83:1 (First gear is 5.3:1).

RPM at 70 mph in 6th gear with 35s tires is 2026. RPMs with 37s would be 1903.

4th gear is 1:1, 5th is .81:1 and 6th is .72:1.

I don’t why you couldn’t try 37s with your current gears, but you’ll probably want those 4.88s sooner rather than later.
 
I don’t why you couldn’t try 37s with your current gears, but you’ll probably want those 4.88s sooner rather than later.
This ^

I personally don’t have experience with 37s on a manual JL, only the 8 speed auto, but would definitely try it, drive it, and wheel it with stock gearing 100% before I spent all that money. It just might be livable. For a little while anyway.
 

waynem

Member
I have the 6 speed manual in my 23 Rubicon. I'm sure this question is asked often, but with 37s and the 6 speed and 4.10 gearing, will I be ok to drive around like that? I already don't use 6th gear except MAYBE on the interstate above 70, which is rare.

TIA,

TerraJL

Definitely going to depend on where you live. Mid-west flats, Florida... you will probably survive. If you are in the mountains, 4.10 will be miserable. We are out in the PNW and went with 5.13s on my wife's JL (manual on 37s) and she couldn't be happier.
 
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