Lift Advice

[Impact]

Hi,

 

I am wondering how much lift can you put in aa comanche before there starts to become major issues

where you have to upgrade the drive shafts and SYE? My intent would be to run 33 or 35 inch boggers.....

I'm guessing enough lift to fix 33's would be the limit... 5"? I now that with my cherokee I have 4.5" with minor

driveshaft vibs and have only had to replace all 4 drive shaft u joints on the jeep, probably more due to

high milage then lift. with 4.5" lift and minor fander trimming I could fix 33's on my cherokee.

[manche]

i have heard you need a 3" lift to clear 32s and with shaved fenders 33's :smart:

[Pete M]

MJs have a longer wheelbase and so a longer driveshaft. About a foot longer than an XJ. Driveshaft angles are never really an issue up to 6 or 7 inches of lift. Other problems crop up with that much lift, but not driveshaft angles.

[Motion Offroad]

The biggest question is what size tires are you going to be running. Boggers are typically an "odd" size and are wider than normal tires are. The extra width and depending on what size rim (8" wide or 10" wide) and the backspacing of that rim will greatly determine what size lift and how much trimming you'll need to do to clear them at full lock.

 

Based on a 12.5" wide tire this is what we recommend with our lifts WITHOUT any major trimming.

 

3" = upto 31" tires

4.5" = upto 33" tires

6.5" = upto 35" tires

 

Now with minor (or major) trimming and proper bumpstops you can fit a much larger tire than recommended above.

[pingpong]

As Adam pointed out... that is very accurate.

The issue with not runing a SYE is the run out on the slip yoke and how it travels out of round. Just if you don't use a SYE make sure you change the u-joints.. cause they get used to runnng at certain angles

[Impact]

As Adam pointed out... that is very accurate.

The issue with not runing a SYE is the run out on the slip yoke and how it travels out of round. Just if you don't use a SYE make sure you change the u-joints.. cause they get used to runnng at certain angles

 

 

So do you mean that I could run a lift kit of 6-7" and not need a sye or cv shaft but all i would need is a longer slip yoke?

I'm guessing that with this high and not using a sye that you would recommend using a t-case drop kit? using a t-case

drop kit though would make a worse front drive shaft angle.... would it not?

 

I was looking at running 35x14 on a 10" (12" would be too much eh?)wide rim.... I don't think they make a 35x12.5 bogger....

 

Is there a manufacturer that anybody recommends for MJ lift kits? and not for 3+g's... thats more for my TJ (future) lol

As for lift i was thinking 1.5 lift springs in a soa setup....

[Eagle]

Nobody mentioned a transfer case drop, except you.

 

Are you asking about MJs in general, or do you know if you'll be working on a longbed or a shortbed chassis?

[Impact]

Nobody mentioned a transfer case drop, except you.

 

Are you asking about MJs in general, or do you know if you'll be working on a longbed or a shortbed chassis?

 

I'm looking a a short box... ya i guess your right, i was the only one that mentioned a tcase drop... is it recommended?

[Motion Offroad]

i was the only one that mentioned a tcase drop... is it recommended?

 

The general rule of thumb on lift height and need for an SYE on the MJ due to the longer wheelbase is at 6.5" of lift. This will vary based on a SWB vs LWB as well as what rear axle your MJ originally had as the driveshaft length vary among these variables.

 

These are general guidelines, and you will hear people needing SYE's at 2" and you will hear of people running no SYE and 6" of lift - it is all dependent on the vehicle and the owners description of "Fine".

 

If you put on a lift, and then notice driveline vibrations, this is most likely due to the rear driveshaft, and could possibly be that you need a SYE and cv-style rear driveshaft.

 

While you may be able to live with your driveshaft vibrations and how that affects you, it is certainly not good for the t-case bearings and seals.

 

The main issue with the factory slip yoke is the increased angles on the rear driveshaft after lifting your MJ. The more lift, the steeper the angle. The increased angles can cause issues with yoke clearance on the factory slip yoke and increased wear on u-joints. A common fix to cure the yoke bind issue is to use a Slip Yoke from a YJ Wrangler. But be advised that what you gain in length, you loose in spline engagement and it's just about a wash (in our opinion).

 

The increased angle also causes a need to shim the rear axle to re-set driveline geometry and reduce vibrations. The problem with re-setting the geometry is that this causes the angles to be even steeper because in most cases, the pinion needs to move down and be parallel with the t-case out put. This increases the angles on the rear driveshaft more and more, and (the biggest issue) causes the slip yoke to be pulled out of the tail-cone more than is comfortable, and can cause the slip yoke to pull clean off the t-case mainshaft during suspension articulation.

 

If a lift kit is sold with a "transfer case drop", or a "high clearance slip yoke" - those are bandaids for a real problem - the REAL solution is to use a Slip Yoke Eliminator and a new cv-style rear driveshaft.

[Impact]

i was the only one that mentioned a tcase drop... is it recommended?

 

The general rule of thumb on lift height and need for an SYE on the MJ due to the longer wheelbase is at 6.5" of lift. This will vary based on a SWB vs LWB as well as what rear axle your MJ originally had as the driveshaft length vary among these variables.

 

These are general guidelines, and you will hear people needing SYE's at 2" and you will hear of people running no SYE and 6" of lift - it is all dependent on the vehicle and the owners description of "Fine".

 

If you put on a lift, and then notice driveline vibrations, this is most likely due to the rear driveshaft, and could possibly be that you need a SYE and cv-style rear driveshaft.

 

While you may be able to live with your driveshaft vibrations and how that affects you, it is certainly not good for the t-case bearings and seals.

 

The main issue with the factory slip yoke is the increased angles on the rear driveshaft after lifting your MJ. The more lift, the steeper the angle. The increased angles can cause issues with yoke clearance on the factory slip yoke and increased wear on u-joints. A common fix to cure the yoke bind issue is to use a Slip Yoke from a YJ Wrangler. But be advised that what you gain in length, you loose in spline engagement and it's just about a wash (in our opinion).

 

The increased angle also causes a need to shim the rear axle to re-set driveline geometry and reduce vibrations. The problem with re-setting the geometry is that this causes the angles to be even steeper because in most cases, the pinion needs to move down and be parallel with the t-case out put. This increases the angles on the rear driveshaft more and more, and (the biggest issue) causes the slip yoke to be pulled out of the tail-cone more than is comfortable, and can cause the slip yoke to pull clean off the t-case mainshaft during suspension articulation.

 

If a lift kit is sold with a "transfer case drop", or a "high clearance slip yoke" - those are bandaids for a real problem - the REAL solution is to use a Slip Yoke Eliminator and a new cv-style rear driveshaft.

 

 

Wow.... thanks for all the info.... are there any companies that make a full 6.5" lift? with new rear springs?

Whats your opinion on using a cherokee skyjacker subframe with control arms? I'm not really a fan of SJ because i have heard alot

of crappy things about their kits....

[pingpong]

Adam made just about every point to be made why you need to run a SYE on anything over 6.5.

 

 

Sky Crapper as I like to call them is ok for some things... not the subframe setup. I know some one who has this setup on an xj, and he has had to replace the joints on them at least once.. maybe more.

 

To be honest for the money there are better kits out there. Most of your MJ kits have you do a SOA swap. thats how we get the 6.5" of lift. Or you will see lifts up to 4" which in the rear is either new springs or a combo of AAL and a shackle.

 

I personally like the last setup I installed, but it is on an XJ (same in the front) I am running the Rock Krawler 3 link. It flexes great, and is really stable on the highway.

[Motion Offroad]

Wow.... thanks for all the info.... are there any companies that make a full 6.5" lift? with new rear springs?

 

Whats your opinion on using a cherokee skyjacker subframe with control arms? I'm not really a fan of SJ because i have heard alot of crappy things about their kits....

The Skyjacker subframe will not work on the MJ's due to the different lower control arm mounts and the way the sub-frame is different than the XJ's are.

 

As far as the rear goes, most 6.5" lifts on the market use SOA with your factory leafs. This helps with the ride quality as well as suspension articulation in the rear. The flatter the leaf is, the better it will essentially flex. Using a 6.5" leaf mean a lot of arch, and a thicker pack that won't flex real well. Not to mention being spring under axle also hinders ground clearance.

 

We tested some 6.5" leafs to use with our 6.5" lift and thought they did the job, however we felt that SOA was the better solution for the reasons stated above.