Jeepin76

I have a 2015, stock 6 speed manual. I have been researching upgrades for about 4 months so I can hopefully determine my plan of attack on my rig. It honestly makes me nauseous thinking about how much this is going b to cost, but I'm doing it anyway. Damn mod fever. Gets me every time!!!

Anyway, I'm probably going to head in this direction. Please let me know what extra mods I need to for or provide any suggestions / alternatives.

* 3.5" RK X-Factor Mid Arm
* Fox 2.0 shocks
* BushWacker Flat Fenders
* 17x9 wheels (Procomp 7005 or 7105)
* 37x12.50's

Will I need a front drive shaft (Tom woods?)? I read that I most likely won't need a rear. Hopefully that is true.

Do you think my axles will last a couple of years until I can upgrade them and do a 5.13 regear?

This is my daily driver with a 20 mile commute each way. I make a valiant attempt to hit the trails or just go explore once a month. My main reason for the 37's is to get my clearance angle close to what my TJ Rubi had with a 2" lift and 33's when going over sharp hill crests. I bottomed out the other day in the JK on a hill the TJ would drive right over. I was not happy.

Thanks,
Matt

Tripletsi

If you're worried about break-over angle I'd protect the underside of the JKU first. Armor it up so you'll slide and not damage anything. Then buy a winch second. Recovery gear is very very important. Third I'd gusset and sleeve the front axle and put in some heavy duty ball joints in preparation for those 37's.

5.13 is a very steep gear for the new Pentastar. Where do you live that you need that kind of gear? 4.56 should be plenty for a DD on 37's.

Good luck!

Tripletsi

P.S. Yes you'll need a new front driveshaft.

D_engel

With 37's, I'd definitely look into some front axle reinforcement (sleeves, truss) with c-gussets as the very minimum. You may also want to add some chromoly rear axle shafts since Georgia wheeling has a lot of slippery climbs that demand a fair bit of wheel spin.

I'd say do a front driveshaft and just get it out of the way. I'm not sure if you still need an exhaust spacer with an after market shaft, so that may be necessary too.

As a general recommendation, I also advise running a set of wheel spacers as well. With 37's and ProComps standard 4.5" backspacing, your tires will rub your control arms like crazy, and adding washers to the steering stops are only going to further limit the Unlimited's already poor turning radius. Spacers will alleviate that problem.

Jeepin76

I did recently add a LoD lite mid width bumper (non recessed) winch mount with a Zeon 10S.

About the 5.13 gears. I shouldn't have been that detailed. I don't plan on regarding until next year or so. I'll do that with the axle upgrade.

Regarding the gussets, are these ACE Engineering ones similar to what I need?
https://www.aceengineeringandfab.com...7.html#page-65

Jeepin76

Check. I'll add that. Is a Tom Woods ok? I probably need a certain length, but I'll figure that out when the time comes.

Jeepin76

I haven't been able to wrap my head around the backspacing numbers yet. I'm guessing I'll need a certain minimum backspacing spec for 35x12.50's or 37x12.50's, since they're both 12.50's. Will the backspacing be the same for both tire sizes because the width is the same? Also, will a higher backspacing number move the inside of the tire away from the axle or vice versa?

I'm starting to think that I should just go with 35's over the 37's. I really like the idea of extra clearance with the 37's, but it sounds like it's a real PITA to prepare for them! Are 35's less of a hassle to run? If I go that route I'll still need the front drive shaft, 3.5" lift, wheels and tires, but I won't need the flat fender flares, chromoly axles and re-gear. I'll may just have to face the fact that my JKU Rubi won't be able to follow my buddy's TJ Rubi (3.5" RE lift on 33's) where ever he goes.

About the sleeves/gussets. Can someone send me a link of who sells them? I found some gussets on ACE Engineering, but no sleeves yet. I would like to have these welded on when I make those RK recommended welds after the RK 3.5" X Factor kit is on.

As for the front drive shaft, I guess I just shop around for a Tom Woods front shaft that is designed for a JKU with a 3" lift, right?

Monte417

First off dont get discouraged or feel overwhelmed from doing what you want to do. If you want to run 37s then run 37s a lot of guys do. Is it more work than running 35s? yeah but its not going to kill you its fun if anything but yes more expensive. It sounds like youve got your build off to a good start with the parts listed. To answer some of your questions you will need a total of 3.5" of backspacing to run 37s and 4.5" to run 35s. Both tires may be the same width but its the height that will make contact with the frame/control arm when fully turned in either direction. The lower the number backspace the further the tire from the axle. You can buy wheels with 3.5" of backspacing to clear 37s or a combination of 4.5"/5" backspaced wheels with a 1.5" wheel spacer to clear. Your front driveshaft may or may not fail if you wheel it every rig is different. Mine never failed but replaced it anyway and sold my stocker to offset the cost. For your front 44 I would without question gusset the c's and add lower control arm skids. If you want add a truss or sleeves but thats your call I have done neither. I will say regearing is the best mod I ever did when I got 37s. I literally can crawl up obstacles I used to have a hard time with. Lastly you will fry your stock balljoints and tie rod ends sooner than later but those you dont need to swap right away only when they are toast. For the rear axle a set of chromoly shafts wouldnt be a bad idea this way you can keep your stockers for trail spares same goes for the front shafts. Keep in mind all this shit you can do in stages

nthinuf

There is information on backspacing, and backspacing -vs- tire size, in both of the threads stuck right to the top of this modified area...


Higher numbers move the rim into the wheel wells, lower numbers move them further out. A 4.5" bs is a fairly common recommendation for a 35x12.50. Down around 3.5"-3.0" is more common for a 37" tire. But there are no one-size-fits-all answers, since builds vary, rims vary, actual tire sizes vary, etc

Quite a few companies sell housing upgrades. Inner sleeves, outer sleeves, truss, c gussets, ca skids, hd mounts, etc. Teraflex, Synergy, offroad evolution, Nitro makes some hammer-in inner sleeves, Rockslide Engineering makes a bombshell inner/outer/gusset kit that is worth looking at, Artec has a very popular truss kit. There are all kinds of options, just depends on your use, needs and budget.

If you go to Tom Woods website, you will find information on how they want you to measure for the new shaft. But they have done enough JK shafts over the last 7/8 years that a lift height should be all they need.

Jeepin76

I really appreciate the info from you guys. Ya boosted my confidence to stick with the 37's path. I can't let my buddy's TJ Rubi have all the fun. I did love my TJ Rubi, but this JKU Rubi drives like a frickin' Cadillac! I can't wait to get most of the build done so I can play on the trails!

One more thing. I'm sure there's a sticky on this, but how do I post a pic in my profile? I did is back when I was on the Vette (C5) forum, but that was pre-wife & kids time frame. I will have another Vette again along with this Jeep by GOD!