Hey guys. I've got an 09 rubicon
So 3.8 with 4:10 gears
Are 37s worth the extra money? How much of a difference do they make?

 

Minimal imo. Ive wheeled with guys on 35 and damn near stock that crawl everywhere some modifed guys on 37s do. Hell hes even done some buggy climbs. Will it make stuff easier, sure, but will the tire size make or break a trail for 99 percent of people? No.

 

I agree 100%. It will make it a bit easier imo but you can do blacks with 35's...actually 33 3/4's if you have BFG's...I would recommend some control arm skids though, mine are beat up pretty bad at this point.

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Depends on how you use the jeep. Improves diff/axle clearance, little increase to break over, but you could just pick a better line

With the 3.8, you'll need/want to regear, even as low as 5.38. You've got a rubi, so your D44 should be fine with some upgrades, c-gussets, chromolly shafts and you'll also want a tuner to recalibrate the new gear ratios, tire size, etc etc...lot more than just slapping new bigger tires on.

The 35x12.5R17 KM2 is nearly the same weight as the 37x12.5R17 KO2, weight is always something to consider...not only for the MPG aspect, but changing a 120+lbs tire alone on a trail can suck.

 

I vote yes!!!

 

I vote yes for what I like to wheel. ROCKS. I need all the clearance I can get. I am on 35s now but 37s hopefully next year.

 

I will echo what Cedo stated in his post and add the below.

Ran toyo 35's for a could of yrs no issues. Had a chance to pick up some beadlocks and 37's for an awesome price. About yr or so after wheeling the 37's, found that the front tires were leaning in. Long side of the axle was bending up due to the weight and wheeling with the 37's. The axle was a dana 44 but had no sleeves or gussets. Upgraded the axle tube to a ProRock44 and all has been well. Upgraded all the axle shafts to RCV's in the front and factory ten in the back. Not sure if they were needed, just wanted the added insurance.

Also, if you run 37's you will need open fenders. You will also probably need to trim your fender wells and if your rear bumper bends around the rear quarter panel that too will need to be trimmed.

If you end up going this route the jeep will perform well off road. On road it will be a dog, even with the 5.38s. To overcome this we put a power adder on the jeep.

 

I would stop at 35" tires unless you want to deal with the extra expense and headaches that 37's can cause. It really comes down to what your plan is with it and if you are not sure I really doubt you need 37's

 

What he said......
Not many even NEED 35s but almost everyone WANTS them and has them. 37s are even less of a NEED but many WANT them. It's life,a game of NEEDS and WANTS. Just try and balance it out.

 

I broke both u-joints and grenade the spider gears this weekend on 35" duratracs. One of the u-joints was brand new and this was on a trussed and gusseted front axle with poly performance ball joints. If not for the armor God knows what else would have broke.