JK high school build

[JK_OWNER_]

Hey everyone, just signed up at this forum, and I’d like introduce myself, just turning 17 soon, (lol) but this lovely 2012 JK sport 2dr was not my first car, I had myself a bmw and my bros kept pushing me on getting on off-road rig, so I took all my savings and got myself an old Montero, and it blew up after being in shop for over 4 months and sold it for same price, and finally bought this JK, fully stock, 96k on odometer, I’m on a budget but I wanna build this rig right and trail rated, that will do rubicon trail.

 

[JK_OWNER_]

So far, only 2 mods has been done to it,
GenRight front Bumper
Badland 12k Apex
Trying to figure out what kind of lift should go for, 3 inch lift or 3.5? Metaloclock or teraflex? Suggestions? (Going on 35s for sure) I wish I could go to 37s but that’s something impossible for me

 

[JK_OWNER_]

Already took it on Walker valley, and was absolutely disgusted and hated it, not because of a horrible trail, but the limits it had, I knew that sway bar links were restricting the flex and play, but when it comes to “almost flipped”, it was definitely sketchy, and I could’ve just grabbed 13mm socket and unbolt the front sway bar links, but I thought i would be fine…nope…. So that made me motivated to get and decent lift, that will significantly increase my uptravel and down travel, and ofc, can’t forget about getting swayloc, something that needs to be done, ASAP.

 

[Qaddiction]

You are off to a great start. Genright has high quality parts. You will be fine with Teraflex, or Metalcloak as well. However, you can't put on a Teraflex suspension while sporting that Metalcloak windshield banner! lol

 

[Dirty Dog]

You're starting from a good place.

A stock JK Wrangler is already capable of running the Rubicon Trail. Doing so is part of the Jeep development cycle, so you're all set.

A 3-3.5" lift and 35's will do you just fine. Avoid the error of too much wheel and not enough tire. You need tall sidewalls for off-highway use. Get a cheap inflator so you can air down. Lower tire pressures smooths out lumps and allows the tire to wrap around obstacles. That wrap means a larger contact patch. Which means better grip. Which means less stuck. Because winching isn't wheeling.

That combo will rub a lot when flexed. At minimum, you will want to do a bit of trimming on your flares and the lip of the wheel well. If you can, replace the plastic junk with good high clearance metal flares.

Quick Disconnects for your swaybar are a must.

You're going to want lockers. When people say they're "on a budget", that often means things like ARB and Detroit are out of the question, so look at lunchbox lockers. They're very inexpensive. And since you're in there doing the lockers, re-gear. You've most likely got 3.73 gears (or worse... 3.21...) and you're going to want more.

You can never have too much gear in the rocks. Like pretty much everything else on the market, the non-Rubicon Wrangler has a 2.73:1 low range. OK, but not stellar. The Gold Standard would be to swap in an Atlas 4 speed transfer case and pick anything up to a 10:1 crawl ratio as needed. But that's not budget friendly. I think the least expensive good option is a Rubicon transfer case. That 4:1 low range makes a big difference.

 

[JK_OWNER_]

You're starting from a good place.

A stock JK Wrangler is already capable of running the Rubicon Trail. Doing so is part of the Jeep development cycle, so you're all set.

A 3-3.5" lift and 35's will do you just fine. Avoid the error of too much wheel and not enough tire. You need tall sidewalls for off-highway use. Get a cheap inflator so you can air down. Lower tire pressures smooths out lumps and allows the tire to wrap around obstacles. That wrap means a larger contact patch. Which means better grip. Which means less stuck. Because winching isn't wheeling.

That combo will rub a lot when flexed. At minimum, you will want to do a bit of trimming on your flares and the lip of the wheel well. If you can, replace the plastic junk with good high clearance metal flares.

Quick Disconnects for your swaybar are a must.

You're going to want lockers. When people say they're "on a budget", that often means things like ARB and Detroit are out of the question, so look at lunchbox lockers. They're very inexpensive. And since you're in there doing the lockers, re-gear. You've most likely got 3.73 gears (or worse... 3.21...) and you're going to want more.

You can never have too much gear in the rocks. Like pretty much everything else on the market, the non-Rubicon Wrangler has a 2.73:1 low range. OK, but not stellar. The Gold Standard would be to swap in an Atlas 4 speed transfer case and pick anything up to a 10:1 crawl ratio as needed. But that's not budget friendly. I think the least expensive good option is a Rubicon transfer case. That 4:1 low range makes a big difference.

For sure. I would probably do an 3 inch lift and 35s nitto tires in a month or so, and I might start saving up for re gearing and getting lockers, maybe if I get enough financing; I’ll get an ARB dual compressor, which is really
Helpful, because I did deflate on Walker valley to 10psi (32s and 17inch wheel). And it did improve grip, I could climb on easy rocks but nothing too crazy, also, I heard many jk owners suggest getting two swaylocs, rear and front, is it worth it?

 

[JK_OWNER_]

You're starting from a good place.

A stock JK Wrangler is already capable of running the Rubicon Trail. Doing so is part of the Jeep development cycle, so you're all set.

A 3-3.5" lift and 35's will do you just fine. Avoid the error of too much wheel and not enough tire. You need tall sidewalls for off-highway use. Get a cheap inflator so you can air down. Lower tire pressures smooths out lumps and allows the tire to wrap around obstacles. That wrap means a larger contact patch. Which means better grip. Which means less stuck. Because winching isn't wheeling.

That combo will rub a lot when flexed. At minimum, you will want to do a bit of trimming on your flares and the lip of the wheel well. If you can, replace the plastic junk with good high clearance metal flares.

Quick Disconnects for your swaybar are a must.

You're going to want lockers. When people say they're "on a budget", that often means things like ARB and Detroit are out of the question, so look at lunchbox lockers. They're very inexpensive. And since you're in there doing the lockers, re-gear. You've most likely got 3.73 gears (or worse... 3.21...) and you're going to want more.

You can never have too much gear in the rocks. Like pretty much everything else on the market, the non-Rubicon Wrangler has a 2.73:1 low range. OK, but not stellar. The Gold Standard would be to swap in an Atlas 4 speed transfer case and pick anything up to a 10:1 crawl ratio as needed. But that's not budget friendly. I think the least expensive good option is a Rubicon transfer case. That 4:1 low range makes a big difference.

I do have 3.73, and for me, since I’m in WA, I’m not always into rock crawling but some mud stuff, so really 2.73 is good for me.

 

[JK_OWNER_]

I do have 3.73, and for me, since I’m in WA, I’m not always into rock crawling but some mud stuff, so really 2.73 is good for me.

3.73 gears in axles and 2.73 in t-case, but if I plan on re gearing, what kind of gears should I look for ? 4.88 ? Or 4.10? Or 4.56?

 

[Dirty Dog]

For sure. I would probably do an 3 inch lift and 35s nitto tires in a month or so, and I might start saving up for re gearing and getting lockers, maybe if I get enough financing; I’ll get an ARB dual compressor, which is really
Helpful, because I did deflate on Walker valley to 10psi (32s and 17inch wheel). And it did improve grip, I could climb on easy rocks but nothing too crazy, also, I heard many jk owners suggest getting two swaylocs, rear and front, is it worth it?

More flex is pretty much always worth it. The one and only reason for having swaybars (more properly called anti-roll bars) is to improve on-road handling, especially hard cornering. For hardcore off roading rigs, they're completely unnecessary. Our JK's both have them (with disconnects) but my YJ (a rig with very limited street time) was built without them, and with no provision for installing them.

 

[Dirty Dog]

3.73 gears in axles and 2.73 in t-case, but if I plan on re gearing, what kind of gears should I look for ? 4.88 ? Or 4.10? Or 4.56?

This gets posted a lot. It's invaluable in any discussion of gear selection.

 

[JK_OWNER_]

More flex is pretty much always worth it. The one and only reason for having swaybars (more properly called anti-roll bars) is to improve on-road handling, especially hard cornering. For hardcore off roading rigs, they're completely unnecessary. Our JK's both have them (with disconnects) but my YJ (a rig with very limited street time) was built without them, and with no provision for installing them.

Yeah, I know there is Anti Rock that is always on off-road mode ish, and swayloc which does Have two mods, City and off-road, and I like that idea

 

[JK_OWNER_]

This gets posted a lot. It's invaluable in any discussion of gear selection.
View attachment 124712

I saw it. And many ppl say, the higher gear ratio is, more weakness it gets and easy to break it, not sure if it’s true tho

 

[Dirty Dog]

I saw it. And many ppl say, the higher gear ratio is, more weakness it gets and easy to break it, not sure if it’s true tho

People say a lot of things. Not all are true, and some of what is true is irrelevant in the real world.

The argument is that lower (numerically higher) gears have more teeth in the same space, therefore they have to be thinner. OK, that's fine as far as it goes. But it ignores the fact that the same change in tooth size means the ring and pinion gears will engage more deeply, resulting in a larger contact patch.

It also ignores the fact that your Jeep doesn't exactly make a lot of power...

My YJ had 5.13 gears in a D44 and Chevy 12 bolt with lockers and beadlocked 40" Bias Super Swamper IROK rubber. Being spun by a 400HP EFI 383ci Chevy through a turbo 350 and Atlas 4 speed. Even with a 10:1 crawl range, and all the torque multiplication that implies, I never broke the differential gears. Plenty of other parts, but not the ring & pinion.

But I'm going to text one of my kids. I've posted his credentials elsewhere, but the short version is an engineering PhD and a job crashing and/or blowing up trains and finding ways to make them safer. Currently working on the Hyperloop project. I'll ask him for a definitive answer and post it when he replies.

 

[JK_OWNER_]

People say a lot of things. Not all are true, and some of what is true is irrelevant in the real world.

The argument is that lower (numerically higher) gears have more teeth in the same space, therefore they have to be thinner. OK, that's fine as far as it goes. But it ignores the fact that the same change in tooth size means the ring and pinion gears will engage more deeply, resulting in a larger contact patch.

It also ignores the fact that your Jeep doesn't exactly make a lot of power...

My YJ had 5.13 gears in a D44 and Chevy 12 bolt with lockers and beadlocked 40" Bias Super Swamper IROK rubber. Being spun by a 400HP EFI 383ci Chevy througha turbo 350 and Atlas 4 speed. Even with a 10:1 crawl range, and all the torque multiplication that implies, I never broke the differential gears. Plenty of other parts, but not the ring & pinion.

But I'm going to text one of my kids. I've posted his credentials elsewhere, but the short version is an engineering PhD and a job crashing and/or blowing up trains and finding ways to make them safer. Currently working on the Hyperloop project. I'll ask him for a definitive answer and post it when he replies.

Sweet, appreciate that

 

[Dirty Dog]

I saw it. And many ppl say, the higher gear ratio is, more weakness it gets and easy to break it, not sure if it’s true tho

Heard back from my son last night.

He says you can make the teeth as thin as you want, as long as you make it from a material that has a yield strength higher than the force to be applied. I think that's true, but also not terribly useful since we can't select gears on that basis.

He also said that the changes in tooth dimension and contact patch would tend to offset, but that they're unlikely to have a significant impact on overall strength due to their relatively small degree. That's kind of what I expected him to say.

His final comment was that the manufacturing process probably has more to do with failure rates than anything else. In other words, if a given ring gear regularly breaks prematurely, buy better gears.

NASCAR teams regularly use gears up to 6.30:1, so clearly you can combine super low gears with high power.

 

[JerryD]

I believe going easy on the skinny pedal and learning to drive with finesse is directly proportional to part longevity.

 

[Dirty Dog]

I believe going easy on the skinny pedal and learning to drive with finesse is directly proportional to part longevity.

Of course. But if your plans include the Rubicon (or similar) trails, the application of loud pedal compression techniques will be mandatory.

 

[JerryD]

Of course. But if your plans include the Rubicon (or similar) trails, the application of loud pedal compression techniques will be mandatory.

That is very true, too.

 

[Danarch]

If going to 3” or higher lift probably will need a different driveshaft(s), exhaust modifications at the crossover, and adjustable control arms. For the tire size will need to change the offset, I’d recommend proper rims, not spacers. I know some disagree with it and like spacers, but just my two cents.

 

[JK_OWNER_]

If going to 3” or higher lift probably will need a different driveshaft(s), exhaust modifications at the crossover, and adjustable control arms. For the tire size will need to change the offset, I’d recommend proper rims, not spacers. I know some disagree with it and like spacers, but just my two cents.

I am going to 3 inch lift, do I really need to get an adjustable control arms? Also, I know that Ill have to mess with the exhaust, which is no big deal for me, but the driveshafts are very expensive as far I know, and I saw few forums saying that for 3inch I dont need em, but some of them, say I do, so do I really need a new driveshafts for 3 inch lift? (and no, im not going higher than that)