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37s - not the tires, everything else around them....

2K views 18 replies 14 participants last post by  Freak 
#1 ·
So I'm debating moving to 37s on my 2-dr. The obvious things are gears and a set of 37s. But what about the rest?? Where does it pay to invest?

Front D44 is ready for 37s - trussed, gusseted, RCV'd. No worries there.
Rear D44 is stock except for Superior evo shafts. Should be okay, I think.
Factory lockers in both.
1310 driveshafts. Wondering about these....rather not move to 1350s unless I have to.

That about covers it? Any other thoughts or areas of concern? The Heep in question is a 2-dr soft top with a couple hundred pounds of Poly under-armor, a winch, and not much else - back seat is out and no heavy bumpers.
 
#5 ·
Driveline wise, you will be FAR more setup that I am when I go 37s. I don't think you have much to worry about. Bolt-on and have at it.

I'll be running stock D44s, just front gussets, and stock driveshafts. :grinpimp:
 
#6 ·
When I ran 37s with the factory 44 in the rear, I broke several Superior chromo shafts, but I didn't have a rubi so you have the bigger spline count. I went D60s and gave up on dumping money into 44s.

My 1310 JE REELS were fine with 37s, no issues. But when I went to 40s, I broke a couple of 1310s in Johnson Valley and have since sold those and went to 1350s.

The only thing I would watch is your Rubi lockers, which seem to fail more often as tires get bigger.

Rear pinch seems will need to be trimmed a little if you are running a real 37s (not a KM2). But this is a quick and easy job. I found that 2.5-3" of lift and tube fenders gave me a flexy little 2-door with low center of gravity with 37s.

Drivability: its funny that when you move to 35s, you really don't notice a difference. But that jump to 37s is where you start noticing the power loss, the benefits of hydro assist, the big MPG drop, and breakage if you don't take it easy in the rocks. At this point, your jeep has crossed the threshold of performing better off-road than on-road.
 
#9 ·
Drivability: its funny that when you move to 35s, you really don't notice a difference. But that jump to 37s is where you start noticing the power loss, the benefits of hydro assist, the big MPG drop, and breakage if you don't take it easy in the rocks. At this point, your jeep has crossed the threshold of performing better off-road than on-road.
That is a very good point. Seems like everytime I think about 35/37 next go-around I flip-flop. I just don't get out and wheel as much as I used to in Nevada. I hate the off-roading out here, it's hard for me to "cross that line", when I don't like the trails.
 
#10 ·
Ball joints....yeah, those are on the list as well.

Thanks for the insight - sounds like I'll be pretty well set up as-is. Other than the overall swine of the drivetrain (which is already a pig with 35s) sounds like I'll be fine.
 
#11 ·
Subscribed, I am on the fence with my 4 Dr whether to move to 37s as my 35s are almost done. But I don't have a nicely setup front end as you do, just a lowly d30 with gussets. You'd be fine.

sent from HTC Thunderbolt via tapatalk.
 
#12 ·
I'd be a little worried about turning 37s with a D30 in the rocks. My fear is that the R&P would become the weak link in the chain and that could make for a nasty break and some collateral damage as well, especially in a heavier rig like the 4-drs. I like that with a reinforced D44 the weak link stays the 1310s in the drive shaft....much easier and cheaper to replace. And, you can get it done on the trail lickety-split.
 
#14 ·
how many r&p failures have you heard of??? not many, yea there are some but very few. I have 4 door ARB locked with 5.13 running 37's that weigh 90lbs per tire alone (no rim no air). I blew through 3 stock axles from breaks at the ujoint then busting the ears or lobes. Now I have upgraded to RCV, sleeved, and gussets. Didn't want to press it too much. Any beating on something for 3 years is bound to break something

don't get me wrong, yea the pinion is smaller , but hell, if you wheel hard enough on 60's with 40's you can still break it. I just don't think people should buy into the hype of the d30 being sooooo weak and fragile. I'm going on 3 years now on that d30. There will always be a weak link no matter what u wheel.

I completely understand your point of view, but this has been debated for several years now and still not many actually proved cases of busted r&p.
 
#15 ·
Other than rim offset it sounds like you have it covered. I noticed a big change in 'feel' when I went from 32's to 35's. But from 35's to 37's, nothing seemed to change or feel different. My rig on 37's rides and drives great on the street and rockes offroad. Post pics after you upgrade!
 
#17 ·
Well after getting home 4am Monday from being broken on the trail for 12 hours, Im getting your setup for the front and rear end. I'm adding dynatrack ball joints for sure and Evo sleeves. I have 37s, 5.38, and blew up the LF axle shaft and ball joints.
 
#18 ·
If you rock crawl with a lot then a hydraulic assist steering would be good. We've broken all the stock steering gearboxes and sector shafts on our Rubi's. Same thing for drag link and tie rod. We beefed them up.
 
#19 ·
I would address the steering. I did everything short of hydro assist. Poly - track bar, drag link, tie rod
 
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