'99 TJ - 3 Inch Lift Advice

[MarkAllan]

I'm thinking this has been asked and answered a 100 times on this site but I'm new here so bear with me as I ask. I'm in the midst of installing a 3 inch Zone Off-Road lift on a 1999 TJ. The kit includes springs, shocks and sway bar links. I have stumbled across people online saying this will throw off the caster which makes sense. I did a bit of math and it will push the rear and front axle off center by about 7/16 of an inch. Is this enough to make adjustable control arms necessary and if so do I get all 8 as adjustable? The kit instructions recommend installing aftermarket alignment cam bolts on the front end because they are not factory installed after 1997. It doesn't say anything about adjusting the caster on the rear axle so that's a little curious, does the rear axle just not matter as much? So in short three questions:

1) Are adjustable control arms necessary with a 3 inch lift?
2) Do both upper and lower control arms need to be adjustable?
3) Is caster adjustment on the rear axle necessary with a 3 inch lift?

This will not be a rock crawler. Some light duty trails (at most class 3 trails) and a fair bit of street driving with some flat towing behind an RV.

 

[AndyG]

Your off center axles require adjustable track bars (which are control arms) and you should get them- you are introducing a 3rd angle into the driveline.

Rear caster is a non issue - rear pinion angle is - you are likely to need adjustable arms and a slip yoke eliminator - you won’t know until it all goes in.

Front caster is very important and you may need at least the 2 uppers adjustable - it is likely going to need more caster and will need the toe reset as well post lift.

There is far more to it than my responses entail- the short of it is 3” is about the threshold where geometry changes have consequences.

Some guys get a complete set and some guys start with 2 front and back and go from there.


Use this forum and you can get there.

 

[MarkAllan]

Your off center axles require adjustable track bars (which are control arms) and you should get them- you are introducing a 3rd angle into the driveline.

Rear caster is a non issue - rear pinion angle is - you are likely to need adjustable arms and a slip yoke eliminator - you won’t know until it all goes in.

Front caster is very important and you may need at least the 2 uppers adjustable - it is likely going to need more caster and will need the toe reset as well post lift.

There is far more to it than my responses entail- the short of it is 3” is about the threshold where geometry changes have consequences.

Some guys get a complete set and some guys start with 2 front and back and go from there.


Use this forum and you can get there.

Thanks AndyG, I've heard 3" is the threshold but I'm committed to doing this right and maybe going a little better than necessary.

The rear pinion angle is a very good point and I'm thinking the upper control arm if adjustable could correct that..that's more a question than a statement.

The toe alignment I have on my radar and I have found some really great "how to" videos and ideas on that.

Your advise on the front caster I think is spot on.thx

I've only installed the lift on the rear so far along with doing new drums, shoes and gas tank skid plate. I'll be turning the jeep around in my garage next week and will start on the front then.

 

[Rickyd]

Here's a picture of how an sye needs adjustment

For the front at 3" lift if you aim the pinion at the tcase or slightly down you should have decent caster. If you use wide wheels it will exacerbate any steering issues

 

[TheBoogieman]

I'm glad nobody told me this stuff before installing my Zone combo lift 7 years ago. ZERO issues.

 

[JMT]

I'm thinking this has been asked and answered a 100 times on this site but I'm new here so bear with me as I ask. I'm in the midst of installing a 3 inch Zone Off-Road lift on a 1999 TJ. The kit includes springs, shocks and sway bar links. I have stumbled across people online saying this will throw off the caster which makes sense. I did a bit of math and it will push the rear and front axle off center by about 7/16 of an inch. Is this enough to make adjustable control arms necessary and if so do I get all 8 as adjustable? The kit instructions recommend installing aftermarket alignment cam bolts on the front end because they are not factory installed after 1997. It doesn't say anything about adjusting the caster on the rear axle so that's a little curious, does the rear axle just not matter as much? So in short three questions:

1) Are adjustable control arms necessary with a 3 inch lift?
2) Do both upper and lower control arms need to be adjustable?
3) Is caster adjustment on the rear axle necessary with a 3 inch lift?

This will not be a rock crawler. Some light duty trails (at most class 3 trails) and a fair bit of street driving with some flat towing behind an RV.

1. Yes
2. Yes
3. No

 

[Gilaguy23]

Consider this. I just did a lift on a 99TJ, 4cyl. As purchased all stock but with 31's. The front tires were less than 2" from the fender flares. At one point the owner installed 2" spacers in front to somewhat level it out. Still it was ass end high and the tire to flare was 4 3/8IIRC. We now have installed 2" lift BDS front springs with no spacers in front, a 1" spacer in back and the space from the top of the 31 to the bottom edge of the OEM flares is 6" at either end. It has the stock CA's, no T case drop or sye, and it has no vibes or weird drivability issues. That is also with NO sway bars at either end as its used mostly on forest trails but does get driven to town 20 miles away on 65mph 2 lane country roads. Like some others have indicated, they rarely ever come out the same once lifted. Coil sag from 25 years is probable. Id do the springs and shocks and bump stop extensions and go from there before wasting $$ on parts you may not need.

 

[GregBelleville]

I'm glad nobody told me this stuff before installing my Zone combo lift 7 years ago. ZERO issues.
View attachment 575868

Is your lift 3" suspension plus body lift? I'm curious because I'm planning to do a 3" lift on Currie springs and I'm curious whether I'm going to get vibes or not without adjustable control arms. I've got a 1" MML already installed which might work in my favor.

 

[MarkAllan]

Consider this. I just did a lift on a 99TJ, 4cyl. As purchased all stock but with 31's. The front tires were less than 2" from the fender flares. At one point the owner installed 2" spacers in front to somewhat level it out. Still it was ass end high and the tire to flare was 4 3/8IIRC. We now have installed 2" lift BDS front springs with no spacers in front, a 1" spacer in back and the space from the top of the 31 to the bottom edge of the OEM flares is 6" at either end. It has the stock CA's, no T case drop or sye, and it has no vibes or weird drivability issues. That is also with NO sway bars at either end as its used mostly on forest trails but does get driven to town 20 miles away on 65mph 2 lane country roads. Like some others have indicated, they rarely ever come out the same once lifted. Coil sag from 25 years is probable. Id do the springs and shocks and bump stop extensions and go from there before wasting $$ on parts you may not need.

Thanks Gilaguy, I'm inclined to follow your advice and get what I have installed and then go from there.

 

[MarkAllan]

Is your lift 3" suspension plus body lift? I'm curious because I'm planning to do a 3" lift on Currie springs and I'm curious whether I'm going to get vibes or not without adjustable control arms. I've got a 1" MML already installed which might work in my favor.

No body lift... that's a rabbit hole I've yet to look down.

 

[TheBoogieman]

Is your lift 3" suspension plus body lift? I'm curious because I'm planning to do a 3" lift on Currie springs and I'm curious whether I'm going to get vibes or not without adjustable control arms. I've got a 1" MML already installed which might work in my favor.

Yes. The Zone combo lift consists of a 3" suspension lift, 1" MML, and 1.25" BL. I swapped my ugly BL for a Black Magic one.

 

[TheBoogieman]

No body lift... that's a rabbit hole I've yet to look down.

No rabbit hole, just an hour of your time.

https://blackmagicbrakes.com/ols/pr...its-97-06-tj-and-tj-unlimited-all-trim-levels

 

[AndyG]

I'm glad nobody told me this stuff before installing my Zone combo lift 7 years ago. ZERO issues.
View attachment 575868

This is a key post-

You may have zero drama

You really don’t know til it is done-

The body lift gives you more height with less driveline change- raises the tub.

Thanks

Andy