What gear ratio are you running with 37"s?

 

Motor and transmission plays a role - but here is a good chart most go by.

 

And...

 

There are about a thousand other 'what gears should I get?' threads for you to read through, those charts are just a starting reference point. Then you look at the engine/trans combo. 2door or 4door. Elevation and terrain (flat roads at sea level or constant hills/mountains at 6 or 8 or 10 thousand feet). A lot of high speed freeway or mostly in town or offroad. Build/overall weight. Actual tire height, since that can vary quite a bit by mfg/psi. And then just plain ole personal opinion.

But for me, 5.38 is the only choice for 37's.

 

more info on what you have for a jeep would make answering this much easier. auto? standard? year?

 

5.13 on 2012 Automatic

 

I'm running 4:88 on 37's with 3.6 and AT. Seems about right for my mods, weight, daily driving, off road terrain, etc. Avg. mileage is 14 mpg and I drive it like I would any of my other vehicles.

 

5.13s on 3.8L with AT and it seems to do okay. I probably would've been better off with 5.38's, but it's still much better than the stock 4.10s my rig came with! The 3.8L is very anemic, though, so even 5.38's aren't going to make it perfect. The minivan motor just sucks all the way around.

 

I was running 5.13 with 37s, just switched to 5.38 noticeable difference with the 3.8 auto. Set my 5.13s up in my dad's 07 he is running 35s worked out well for both jeeps.

 

2009 JKUR Auto 37's 5.38's