New OME 2.0 lift questions

ac_ said:
I have that exact pack sitting in my living room right now so I could, and I am considering it. but I am leary to go up anymore in front because I am at the end of my new sway bar links and my steering is under-steering as it is. If I go up any more, I will need to add adjustable control arms. Not the end of the world but if I go down in the rear I think it will fix my understeer and save me some adjustable control arm moneys.

Besides all of that, I am thinking I might need to pull the rear spacers and add the 3/4 in front anyway, so I think I am going to start by pulling the rear first and see what I get from there,

I am excited to see how yours turns out.
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I'm my head by me removing the rear pucks alone it just didn't add up to me. I'm going to have to pull the pucks in the rear and add the 3/4 spacer. I may or may not have to stack them tho. That's the part that's going to be iffy. Do I stack it or just pull the fronts also and add the 3/4" spacer. We shall see
 
Starrs said:
I'm my head by me removing the rear pucks alone it just didn't add up to me. I'm going to have to pull the pucks in the rear and add the 3/4 spacer. I may or may not have to stack them tho. That's the part that's going to be iffy. Do I stack it or just pull the fronts also and add the 3/4" spacer. We shall see
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That is where I am because it is so much more work to do the fronts compared to the rears. I think you kind of want to wait and see how mine turns out but I want to wait and see how yours turns out lol. I have all of the same concerns and parts as you do so I can do that too.

My biggest worry is that if I stack them, I think I will definitely have to get some adjustable control arms, but if I take out the 10mms and replace with 3/4's then when all said in done I will get a tiny bit over 1/4 inch taller in the front(if I don't stack)

Basically if I take the rears out it will drop the rear almost a 1/2 inch and if I put the 3/4 in the front it will move up 1/4 if I don't stack. Ultimately I think that will be what I end up doing. but I am going to start with the rears and drive it with some weight in the rear and see how it goes.


For those interested, The light rears so far, i don't notice really any ride quality differences from the heavy to light. I do notice a little more body roll around corners, but it is kind of a cool jeep thing, but going over bumps not really any noticeable differences. I haven't been offroad but I don't see that as being any different. I think heavy fronts w light rears if you have no weight or oversize tires is the way to go so far. Now it is just the matter of shimming it to my/your liking.
 
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ac_ said:
That is where I am because it is so much more work to do the fronts compared to the rears. I think you kind of want to wait and see how mine turns out but I want to wait and see how yours turns out lol. I have all of the same concerns and parts as you do so I can do that too.

My biggest worry is that if I stack them, I think I will definitely have to get some adjustable control arms, but if I take out the 10mms and replace with 3/4's then when all said in done I will get a tiny bit over 1/4 inch taller in the front(if I don't stack)

Basically if I take the rears out it will drop the rear almost a 1/2 inch and if I put the 3/4 in the front it will move up 1/4 if I don't stack. Ultimately I think that will be what I end up doing. but I am going to start with the rears and drive it with some weight in the rear and see how it goes.


For those interested, The light rears so far, i don't notice really any ride quality differences from the heavy to light. I do notice a little more body roll around corners, but it is kind of a cool jeep thing, but going over bumps not really any noticeable differences. I haven't been offroad but I don't see that as being any different. I think heavy fronts w light rears if you have no weight or oversize tires is the way to go so far. Now it is just the matter of shimming it to my/your liking.
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Where did you do your measurements at to determine your rake?
 
Daz7 said:
If you lower the rear it will induce more understeer.

To add understeer - higher front or lower rear ride height
To add oversteer - lower front or higher rear right height
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Maybe I got that terms backwards I don't know, but to clarify here is what is happening
Before lift kit steered fine at all speeds,

After lift kit I could turn and the steering wheel would return fine to home, on the freeway, it would wander back and forth like a shopping cart with really loose front wheels.

When I lowered it back down 3/4 of an inch it still wanders but instead of starting at 40 mph it starts at 65mpg but still comes back to home on turns fine

I am assuming lowering another 1/2 inch in the rear will fix it even more.

If it doesn't, I will buy adjustable control arms and make it work right.
 
ac_ said:
Maybe I got that terms backwards I don't know
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un·der·steer
verb1.
  1. (of a motor vehicle) having a tendency to turn less sharply than is intended
*This can also be referred to as "pushing". It sounds like you are dealing with neither understeer, nor oversteer. Yours is wandering, which is an entirely different animal.
231px-Understeer-right-hand-drive.svg.png

Understeer: the car does not turn enough and leaves the road
231px-Oversteer-right-hand-drive.svg.png

Oversteer: the car turns more sharply than intended and could get into a spin
 
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That's castor, you'll need adjustable control arms to help dial that out.

Look, the OME kit isn't perfect but is a cheap way of getting up to 2.5" lift. This is without the hassles/cost of SYE's and control arms etc. The problems arise when people buy the OME kit because it is cheap and then start adding spacers to get even more lift as you start to run into the issues you'd having now.

In truth, buy the OME kit and use it as it was designed for - a 31/32" tyre. Want larger get a more complete kit like a Currie 4" or the like.
 
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Squatch said:
un·der·steer
verb1.
  1. (of a motor vehicle) having a tendency to turn less sharply than is intended
*This can also be referred to as "pushing". It sounds like you are dealing with neither understeer, nor oversteer. Yours is wandering, which is an entirely different animal.
Click to expand...

Understeer is when you go into a corner and the car wants to go straight ahead.
Oversteer is when the back of the car wants to come out as you come into a corner.

In a TJ, you'll probably only ever see the differences in this on a loose dirt road or in the wet on the road then you come into a corner too hot.
 
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Squatch said:
Correct me if I'm wrong, but his toe-in/out adjustment can also create wandering (though I don't see how a lift height would have anything at all to do with that setting...).
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It's castor as when he dropped the front it got better. ie the axle housing rotated toward standard more, it's ball joint angles in the TJ or king pin angles in a normal car that your changing when raising/lowering.
 
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Daz7 said:
That's castor, you'll need adjustable control arms to help dial that out.

Look, the OME kit isn't perfect but is a cheap way of getting up to 2.5" lift. This is without the hassles/cost of SYE's and control arms etc. The problems arise when people buy the OME kit because it is cheap and then start adding spacers to get even more lift as you start to run into the issues you'd having now.

In truth, buy the OME kit and use it as it was designed for - a 31/32" tyre. Want larger get a more complete kit like a Currie 4" or the like.
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Bingo! The problem is driveline angles take precedence over castor angles.
Squatch said:
Correct me if I'm wrong, but his toe-in/out adjustment can also create wandering (though I don't see how a lift height would have anything at all to do with that setting...).
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Yup. Lifting a TJ can change the toe in angle because the axle gets rotated as the lift height changes. It's best to check after a lift or installing bigger / smaller tires. Body rake does change your castor angles on the TJ. Not a lot can be done about that though.
 
Daz7 said:
It's castor as when he dropped the front it got better. ie the axle housing rotated toward standard more, it's ball joint angles in the TJ or king pin angles in a normal car that your changing when raising/lowering.
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Yep. I know what caster/camber/toe-in is. I was just saying that if I recall correctly, toe-in/out adjustment can also create a condition where a vehicle will wander. :)
 
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StG58 said:
Yup. Lifting a TJ can change the toe in angle because the axle gets rotated as the lift height changes. It's best to check after a lift or installing bigger / smaller tires. Body rake does change your castor angles on the TJ. Not a lot can be done about that though.
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Now that is something I can honestly say I was unaware of. Thanks, @StG58.
 
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Holy Cow...This thread is getting good! Some good suspension knowledge coming through. I know enough to be dangerous (from driving FormulaSAE cars in college) but typically don't post much because I'm definitely NOT an expert. @Daz7 has got it down, so does @Squatch . Both on spot on with the wandering. Probably Castor angles, but toe out will cause high speed instability as well.

Anyway, Since I'm heading down the OME lift path as well, I told @ac_ I'd post up some before numbers. I measured in the same spots as the others. I'm sitting on 32's (255/75R17) BFG Mud terrains that are >75% tread, Full tank of gas, and 3/4" spacers on all 4 corners with factory springs. 04 Rubicon. My Driver Front measured right at 16", Driver Rear was 16 3/8", Pass Front was 15.5" and Pass Rear was 16 3/8. I also tried to measure my roll centers, front and rear. Came up with the Rear at 21 3/4" and the Front was 18 3/4. Those are estimates obviously...just some marks on my garage floor and eyeballing things. No frame jig to really get crazy.
 
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Ranger_b0b said:
Holy Cow...This thread is getting good! Some good suspension knowledge coming through. I know enough to be dangerous (from driving FormulaSAE cars in college) but typically don't post much because I'm definitely NOT an expert. @Daz7 has got it down, so does @Squatch . Both on spot on with the wandering. Probably Castor angles, but toe out will cause high speed instability as well.

Anyway, Since I'm heading down the OME lift path as well, I told @ac_ I'd post up some before numbers. I measured in the same spots as the others. I'm sitting on 32's (255/75R17) BFG Mud terrains that are >75% tread, Full tank of gas, and 3/4" spacers on all 4 corners with factory springs. 04 Rubicon. My Driver Front measured right at 16", Driver Rear was 16 3/8", Pass Front was 15.5" and Pass Rear was 16 3/8. I also tried to measure my roll centers, front and rear. Came up with the Rear at 21 3/4" and the Front was 18 3/4. Those are estimates obviously...just some marks on my garage floor and eyeballing things. No frame jig to really get crazy.
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Thanks for playing RB. It's all relative at this juncture, but it's cool that we can have some real world data that we can compare to.
 
RECAP and UPDATE and SOLVED


I am not sure if @Daz7 understands or read the beginning of this thread, but I was not trying to get more lift out of my OME. I simply wanted it levelish. With the heavy kit on my Jeep it actually gave me just a touch under 4 inches of lift in the rear and barely 2 inches in the front. This did all sorts of crazy things to my jeep. I am also running 31 duratracs and do not intend on running bigger tires. I was just trying to figure out how to level it.

RECAP
The way the kit was I installed the heavy kit with the 10mm spacers front and rear because that is what comes with the kit. It wouldn't even roll out of my driveway that way. I had to lower the pan to get the driveline to turn. It bucked and knocked and was pissed. I did a 3/4 pan lower and it would drive but still vibrated on take off. My steering WANDERED really scary at 40 mph and above.

I wasn't satisfied that the kit had a 2 inch rake when it was only a two inch kit. Plus it handled bad even with the alignment. So I called ARB, and showed them a picture of my Jeep and they agreed that it had way too much rake and said it was because I had ordered heavies for the rear but have no weight or t big tires on the rear.

We talked for a while and he said that the spacers aren't always necessary and that all tj's are different and sometimes they have to cross the A's with the B's and add and remove spacers to get it right.

I don't believe anybody is buying a 2 inch lift then adding spacers for more lift. I think we are adding spacers to level it out because "All TJ's are different"

UPDATE
So He suggested I buy the light springs for the rear. I contemplated it for about a week then just went ahead and did it. And low and behold it dropped about 3/4 of an inch. The vibrations went away and then the steering got better. It started to wander at about 60 +. Still too much rake for my taste so tonight I decided to remove the 10MM spacers in the rear.

I was really sick today but decided to muster up some gumption and just getr done. I removed the rear spacers and drove it and it was super smooth and leveled out to about a 1/2 inch rake. I am pretty happy with that. I could remove the 10mm spacer in front and add a 3/4 spacer and that would level it out perfect but sometimes I do tow my quad on a light trailer so I will be happy with a 1/2 inch rake.

So breakdown what worked for me
98 TJ 4.0 5s /w winch and winch bumper and dual batteries.
OME 2.0 heavy lift in front with heavy shocks and 10mm spacer
OME 2.0 Light lift in rear with no spacers
left me with 1/2 inch rake.

After this I drove it and and it looked good so I brought it back in the shop and removed they tranny pan drop, and drove it again and with the exception of a slight take off vibration it is vibration free and the steering seems tight at all speeds now. I brought it back into the shop and re-aligned it and it was actually at 1/8 toe and I moved it to 1/16th. It didn't make any difference that I could tell on the test drive after that, but I think it is all done now.

So @bobthetj03 @Starrs @JMT @Ranger_b0b I think my journey is finally complete. Somebody mentioned earlier I think in this thread that I shouldn't have to lower my trans for a 2 inch lift and when I finally achieved that it seems to be true. I am hoping this helps others that have questions about the OME, but I think it is important to get the right springs for your TJ. There will be a lot less hassle if you do.

For me the difference between the light and the heavy wasn't ride quality as much as road height. The heavies gave me more ride height because I wasn't sporting enough weight.

Anyway here is a my done deal.
IMG-0059.JPG
 
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Ranger_b0b said:
Holy Cow...This thread is getting good! Some good suspension knowledge coming through. I know enough to be dangerous (from driving FormulaSAE cars in college) but typically don't post much because I'm definitely NOT an expert. @Daz7 has got it down, so does @Squatch . Both on spot on with the wandering. Probably Castor angles, but toe out will cause high speed instability as well.

Anyway, Since I'm heading down the OME lift path as well, I told @ac_ I'd post up some before numbers. I measured in the same spots as the others. I'm sitting on 32's (255/75R17) BFG Mud terrains that are >75% tread, Full tank of gas, and 3/4" spacers on all 4 corners with factory springs. 04 Rubicon. My Driver Front measured right at 16", Driver Rear was 16 3/8", Pass Front was 15.5" and Pass Rear was 16 3/8. I also tried to measure my roll centers, front and rear. Came up with the Rear at 21 3/4" and the Front was 18 3/4. Those are estimates obviously...just some marks on my garage floor and eyeballing things. No frame jig to really get crazy.
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Please keep us posted in this thread and let us know how your install goes. Not that I am a 4link suspension expert by any means, but it is fresh in my mind if you have any questions. Don't forget to post pics....
 
StG58 said:
Kudos, you done good wading through all that. Looks good, bye the way. Hope you feel better soon.
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Thanks I do feel better already knowing I am done tearing down my suspension for a while. I am going to install my new 5 1/4 speakers in dash tomorrow, and might have to straighten the steering wheel a tiny bit, but other than that I am going to take it easy tomorrow or should I say today hehe.

Thanks again.
 
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