Handling never been the same since suspension work...?

[rraedeke]

I know that when I put on the OME shocks and torsion bars on my cruiser it changed the geometry of the IFS. But ever since having this suspension work done, the cruiser has never handled right again. The truck seems to wander and I guess you would call it hunting. The steering just doesn't feel solid. Yesterday I drove on a section of road that was in the process of repaving. I had the left wheels on the new blacktop and the rights about 4" down on the grooved. The steer wheel was pulling to the left and when I let go I thought it would run right off the road... When driving on the highway the truck just seems to start heading off to either direction - perhaps an effect of the semi tractor-trailer ruts.

I've lifted each front wheel one at a time to see if there was any play and I get a little, but nothing major. I see the arm attached to the rack and pinion move a little.
I just rotated my tires to see if poor tire wear was the cause and that hasn't changed things.

When I make a sharp turn my tires squeal as if they are not aligned, and if I turn it sharper it feels like one of the wheels is jumping as if the differential is binding up. Slee did a full alignment in January after they installed upper control arms, so I'm not thinking it's an alignment issue.

I've looked at the bushings, etc. and nothing jumps out at me as the culprit.
Slee, another 4x4 shop and my neighborhood garage all have looked at it and report nothing out of the ordinary.

Is this lift job / geometry change really to blame and is this just normal. With so many 100's having had after market suspension installed I'd think there would be some discussions about this.

Anyone have some recommendations for me... other than go back to stock.
Thanks

 

[paflytyer]

First, check to make sure your center diff isn't locked. The indicator light may not be working. That could explain the "jumping" on pavement during turns. Then, try lowering the front a little via a tbar adjustment. Even 1/2 inch could make a difference. The front end should be about an inch lower than the rear.

EDIT: I see you've already been to Slee. They will take care of you either way.

 

[rraedeke]

Ben at Slee said they were going to adjust that down from the level stance attempted by the 4x4 shop. I assume you would measure from ground to the underside of the wheel arch... if so - the front is actually 1/2 higher...??

Since the time that Ben's team lowered the front end (when they put the UCAs on and did the alignment) I have installed their rear bumper. A beast that could account for the new stance? I have toyed with installing an ARB front bumper that might counter balance it, but think I will put some new NITTO tires on first.

I'm not real sure I want to mess with the T-bars myself, so perhaps another trip to Slee is in order.

The last time I engaged the differential lock the light came on - I will try again... How else can I tell if its free?
I also wonder if the combination of the abrupt down angle of the axle and the rotation of the wheel isn't causing an issue with the CV joint that might bind it up enough to slip that wheel...

 

[paflytyer]

Level stance is no good on the 100 series. You need a "raked" stance for the truck to maintain a happy ride on the road.

PM sent

 

[spressomon]

#1) Set the front ride height...then adjust the rear accordingly.
Q: What are your current alignment and resting suspension height specs?

#2) Set the resting front suspension height to no more than 20.5" as measured straight up from the centerline of the front hub to the lower lip of the front fender and you're life will be mobetta in the steering, durability and handling departments of a UZJ100.

#3 You will also benefit, given a raised 100, aftermarket upper control arms (UCA) that allow increased caster adjustment compared to stock. Caster is one measurement that will bring improved stability to highway speed cruising and general off-road usage. Based upon reviews here the new-ish SPC UCA units seem to offer superior benefits whilst avoiding some of the glaring negative performance and/or durability issues of other types/brands of UCAs for the 100 platform.

 

[TeCKis300]

Caster

You didn't mention if you upsized the tires, but that is typically the modification that exascerbates this issue.

Rake, as mentioned above with the front end being slightly lower than the rear, also affects caster. Basically as you lift the rear, it changes where the angular position the front tire will contact the ground, which is part of the parameter the defined caster.

Do you have a print out of the last alignment? I'm not sure the caster is directly adjustable on the hundy, other than indirectly via rake.

 

[rraedeke]

The Slee alignment was done in January - I have the print out at home. The rear bumper install was in May - I assume that added weight will throw off the alignment somewhat.

Slee installed the SPC UCA and then did the alignment - as I recall it looked nearly perfect. I can scan the print out and post it later.

A quick measurement from center of wheel to underside of wheel well is about 22" all around?
I was under the impression that the rear ride height was a given based on the springs and shocks and that the only adjustment was the front by way of the T-Bars. I'm still learning.

I have stock wheels and tires - if bigger tires is going to make this worse, I need to rethink that.

 

[spressomon]

A quick measurement from center of wheel to underside of wheel well is about 22" all around?

If your front resting ride height is truly 22" then this is your culprit. Lower, as I mention above (plenty of 'how to' threads for adjusting t-bars for a little search time), the front ride height to 20.5" (or less) and test it. You will find much better stability at all speeds but especially at highway speeds. You will also gain durability enhancement for CVs, steering rack and all related parts due to the relatively more friendly angles of same.

Having said that I'd be surprised if Slee set the front ride height at 22".

Regarding the rear suspension height: Different coil springs and/or coil spring spacers will be how to adjust rear ride height. You could also deploy air bags inside the coil springs to allow further load and/or height adjustment; however as with most things they are not perfect...but for certain applications provide a net positive sum for some folks.

Tire size: With the SPC arms you can get enough caster adjustment to play friendly with 35" tires if this is your intended direction. 35" tires actually have other more serious considerations IMO: Clearance issues, braking differences, effective gearing issues, power transmission issues, etc., than their effect on caster and/or steering (relative to your SPC arms). None of these are insurmountable but you do have to think it through so you are prepared to deal with them as/if needed (always good from a budget perspective ).

Dan

 

[rraedeke]

I'm going to measure more accurately when I get home. Knowing the reputation that Slee has in this industry, I too would be surprised.
The jeep 4x4 shop that I initially took it to a couple years ago... well that's a whole different story!
I assume the print out I have at home should tell me what those heights were when they did the alignment.

I was thinking of getting some Terra Grapplers in a 285/75 16 - but it sounds like I need to do some more home work to be sure I don't cause myself unintended consequences.

Thanks for the help.
Richard

 

[Bloomer]

I recently installed a 2.5 OME suspension with Slee heavies. Originally had stance almost level and experienced some of the same type of symptoms you mentioned. I lowered the front end 0.5 inch to 21 inches and handling improved tremendously. That's still a little higher than recommended above, but I noted a big improvement in handling after lowering just 0.5 inch.

The other thing I noticed is that it handles and rides much better when loaded up. I have the Slee rear bumper but can tell it rides and handles better with additional weight in the cargo area (thinking that's justification for a drawer system and fridge).

I don't think it will ever handle as good as it did before installing the suspension.

 

[spressomon]

Everyone's tolerance of the change in gearing effect larger tires have on any rig will be different. For me, then living and exploring at ~5,000'+ left me unhappy with the stock gearing and 33" tires (then 285/75R16 Goodyear MT/R). The shift points were off and generally felt awkward. In fact the next change with 35" tires and 4.88 gearing on my '99 resulted in better overall performance, including slightly better MPG, for me/my '99 despite the heavier and larger diameter tires.

The advantage you have: There is a plethora of data within not only the 100-Series forum but also MUD in general for which to make better decisions when it comes to alterations on your 100!

 

[rraedeke]

Here is the alignment document from Slee -
As expected the front was set at 21.85" and when I measured this tonight - it's spot on.
The back was set at 22.85" and it too now measures 21.85".
So more than likely the 1" drop is due to the added bumper weight.

 

[spressomon]

Here is the alignment document from Slee -
As expected the front was set at 21.85" and when I measured this tonight - it's spot on.
The back was set at 22.85" and it too now measures 21.85".
So more than likely the 1" drop is due to the added bumper weight.

Caster is spec. Lower your front, via t-bar adjustment, 1" and you'll be golden. If you feel and like the difference at ~20.5" then you might want to have your alignment checked again. FWIW I'm running almost 4 degrees of caster and its great. So as you lower your front suspension height your effective caster # will come up a little...all good in my book.

 

[rraedeke]

I'm going to drop the front today as suggested. Per some other posts, I am going to mark the current position so I can see how far I've turned the bolt.

I would imagine each torsion bar will be different, but does anyone have a roughly right rule of thumb.. How many turns on the bolt per 1inch of lift or drop on the front end.

Other than raising each wheel and turning the bolt, driving it around the block and measuring the new height, is there anything else I need to be doing?

Thanks

 

[spressomon]

About 1/8" in height per torsion bar adjustment bolt 360. After you upset the apple cart, by adjusting the torsion bar pre-load, it will take a little time on the road/trail for the resulting suspension height measurement to become static. For your shake-down test drives post adjustment turn the steering wheel rapidly back/forth to load/unload DS and PS...helps settle the t-bars.

Yes...always take the weight off the suspension when adjusting the torsion bar preload and Better to take measurements on flat level ground.

 

[rraedeke]

Each side took 8 full turns. Seemed to drop the front to 20.5".
I am going to drive it this week and measure it again on Friday.
It feels a little too angled, but the initial test drive was promising.
Will know more tomorrow.

So here is a question.
What keeps that bolt from just rattling loose and backing the torsion bars down?
There is no keeper pin or anything.

 

[rraedeke]

So I finally got around to remeasuring the truck after my T-Bar adjustments.
Measured from the center of the wheel to the bottom of the wheel well.
Rear - 22.5"
Front - 20.5"
Looks like dropping the front, has raised the back a half inch.

It has taken a little bit getting used to the new angle, but it handles a ton better.
The drop on the front has flattened out the angle on the CV joints. And the jumping I was experiencing when turning sharply has also disappeared.

Might consider 2 turns back into the bars, but I am going to drive it up to Breck next weekend and see how she handles I-70 before I make any further adjustments.

Next steps for the truck:
Replace the muffler with a Magnaflow.
New tires... Just need to decide which ones.

 

[SWUtah]

Slee did mine at his shop, I wanted it level. Rides great, never a problem and even tire wear.

 

[Sari AlHiari]

#1) Set the front ride height...then adjust the rear accordingly.

How do I adjust the height of the rear?

 

[spressomon]

^ Different springs; coil spacers; internal coil air bags; mass

Also if you run mono-tube nitrogen charged style remote reservoir shocks, 2.5" or larger are more effective, (Fox, King, Radflo, etc.) you can, by altering the nitrogen pressure inside the remote reservoir, get a little (1-2") increased height/load leveling [as well as increased effective compression damping (with top mounted hose on the shock)...].