TJ ride quality

[maximumrob]

stock '06 rubi unlimited, and the ride quality off-road is pretty bad. Even with the longer wheelbase of the unlimited, I could swear there are leafs holding the axles on

On a short-arm (stock) type setup, is an OME kit enough to smooth things out or do I need to up my medical plan to afford the oncoming kidney transplant?
The ride quality is horrendous - rockier sections of trail or road come close to giving me a concussion.

Just curious what some other folks have done to make the longer hauls more friendly to children's teeth and my internal organs.

cheers
-isaac

I'm not sure what all the other posts have written in them, but I found the ProComp 2.5" spring lift with the adjustable MX-6 shocks to ride extremely well. I run with the shocks on the softest setting and it's great! When I ditched the stock LCA's with worn bushings for new JKS units, the ride improved even more.

However, the ride deteriorated greatly when I put the loosey-goosey AntiRock swaybar on it. Run the stock swaybar if you can stand not to mod it.



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[Matto0]

I'm a new LJ owner, and I have to agree, the ride is more trampoline like than I envisoned it would be. It flexs good and goes over rocks just fine, but it is extremely stiff on the road, and yet it bottoms out in the rear over very small whoops at very very low speeds.

It has a Currie 4" short arm lift kit, with Rubicon Express 4.5" springs, Rancho shocks, a 1" body lift, Currie Anti-Rock pnuematic disconnects, Currie HD steering damper and tie-rod kit, a Rubicon Express tummy tuck, and it's rolling on 35" ProComp XTerrain's on the stock Rubicon 17" rims. I would describe the ride a "disconcerting" at best, and "trampoline like" normally.

The ride is very stiff and bouncy, but that could just be a Jeep thing, I really don't know. But in cornering on the street, the rear end feels like it's tucking and wallowing. On the trail, the rear end bottom's out on mild woops on sandy trails, at SLOW speeds (10 mph or less). At exactly 50mph, there is a considerable "shimmy" in the truck, with the windsheild giggling side to side several inches, and everything rattles, but only right at 50mph. Above and below, it's pretty smooth if the pavement is smooth.

Anyway, with these problems, I'm really not sure were to start. I am confident this is not "right", but I don't know what I can do to rectify it.

Also, what's the deal with those tie downs in the rear? Can anything actually fit under them?

For the Shimmy around 50... get your tires balanced at a good shop (allot of shops will get them close, but close doesn't mean much with such a large, heavy tire).

For the lift stiffness, those RE 4.5" springs run 1"+ greater in lift and have an extremely high spring rate, and you are on short arms (even if they are some of the best out there). I would say thats the biggest issue.

Depending on your shocks, a better set of shocks my help some but 5"+ of lift on short arms will give a harsh ride. RE has a long arm upgrade kit so you don't have to buy a whole new lift, I'm not sure what you would need to use it. You could also consider shorter springs.

Keep in mind it is a Jeep, its not designed to go fast off-road, but I do think you could improve your on-road ride (long arms and good shocks would go a long way here). BTW... nice jeep man!

 

[madizell]

It isn't just a "Jeep thing." You are describing a badly tuned suspension. Nor is the problem that Jeep wasn't designed to go fast off road. My 5,300 pound CJ-7 with SOA leaf springs has often done better than 65 off road in Outback racing conditions, and more than 85 on rough dirt roads with only 13 pounds of air in the tires, but still handles nicely on the highway with finger light steering at 90+ speeds. It can be done. Now that I have coil-over in front, the speed limit has been raised by 10 or 15 for all conditions.

The TJ is even more capable, and there is no reason why a coil spring vehicle can't be made to articulate and also ride well with lift. Something is out of balance if you have bouncy stiff ride and no body control.

My guess is you need to reinstall anti-sway equipment to start. Currie Anti-Rock is very good here. Shocks are next, as they sound as if they are far too stiff to do the job. However, suspension is a complicated issue that probably can't be de-bugged online. Find someone in your area with the knowledge and experience to sort out your suspension.

I would not assume youe need to remove, replace, or grossly modify the suspension you have. You need to first find out why it rides a badly as it does. It could be something simple like way over-tightened long arm bushings.

 

[nwoods]

Hey guys, I had a long response typed out, then lost it in a screen refresh. SIgh...

I agree that I suspect the suspension is not tuned properly.

Speed: I can't imagine driving this thing over 70mph on the highway, I am whiteknuckling it at 65mph. I can't image this thing hitting 90 mph unless I was going off a cliff

Off road, I have gone very slowly only, usually in a long train of other Jeeps. The bottoming out is happening at very slow speeds, typically less than 10mph, with two small kids in the back (and a heavy 35" tire) and two big adults in the front. Steel Hansen bumpers all around, with a Warn 9,000 winch in front. No hardtop, no tool boxes, cargo, etc... A pretty light set up all things considered.

The on-road wallowing is at slow speeds, such as turning a corner at an intersection. Rear end feels like it's tucking.

I learned that I have Currie 4" springs in front, Rubicon Express 4.5" springs in back, and Rancho RS9000 adjustable shocks at all 4 corners. I'm going to play with the shock settings this weekend.

Madizell, I have the Currie Anti-Rock disconnectable swaybar system in the front, and it appears to be working properly. "engaged" when on road, and disengaged pnuematically when off-road.

As for the 50mph shimmy, I should state that it seems to only occur on-road, when I am aired up (37-38psi with 35" ProComp XTerrians). The tires were recently balanced by a competant shop, and they moved a lot of weights around to get them to balance. They were really out of balance before hand. The shimmy is reduced in speed range, but still at the same strength at 50mph as before balancing. I was aired down (20psi) last weekend for a short portion of the road into town at the end of the trail, and it did not shimmy, but I am not really sure if I got up to 50mph. May not have. I will test that out this weekend.

There are hundreds of off road shops in SoCal, strangly, none near my home, and few open on weekends. Sigh.

 

[madizell]

I can't imagine why you would need 38psi in your tires for a relatively light vehicle. Running that hard a tire will make any alignment or steering component compliance issues that much worse, and you will only be running on the center of the tread. Air down to somewhere around 24psi, get your tread back on the road, and see if there is a difference. Running that hard a tire will also cause a bouncy and harsh ride no matter whose suspension you have.

Bottoming out at slow speeds on any but extremely harsh drops should not happen if you are not overloaded. Verify your shocks are working. I use Rancho 9000's as well, my rig is heavier than yours, and I don't have bottoming issues even when the shocks are set on soft settings (I am using 10-leaf National custom packs, built for the vehicle). If the shocks are working at all, your springs may not be up to the job, or your bump stops may be placed incorrectly. How much up travel do you have in the back? I would expect something like 5 inches more or less.

 

[outdoors]

How's it going..
Reguarding the shimmy, if it's truely in the rear 1st check your trac bar bushings and bolts first check every nut and bolt even check the shocks too. You should also check all control arms and bushings front and rear as well.
Also I never run over the recommended stock tire pressures even when running much bigger tires. Mine says 29 psi, so there's my max tire pressure for the Jeep. Nothing wrong with trying 24 but with the weight you have carrying passengers you may find 27-30 PSI works best.. I hope this helps... Also when you say bottoms out in back.. Is it hitting on the body or bumpstops?

 

[nwoods]

Hi guys, this is my first time owning anything with tires this large. Up 'til now, my 31.5" diameter 285/60/18's were the biggest I have had expereience with. So I am virgin when it comes to sorting out tire pressures on these tires. I recently lowered the pressure to 32 for street use, and didn't really feel any major change. I went off roading last weekend and went down to 18 psi and still barely had any deflection, though I had no traction issues, far from it in fact.

I will play with mid-20's for street pressure and see how that does. I don't want to jeapordize saftey (stablity) or rolling resistance (gas mileage and tire wear) too much, so finding the sweet spot is important to me.

As for bottoming out, the trail I went on last week (John Bull Trail in Big Bear, CA), is 5 miles of large granite rocks. I did not ever bottom out, and the articulation was awesome! So I'm not sure now quite what the right balance should be. When I did bottom out the previous week, it was just to the bumpstops, which are set to just clear the tires from inside the wheel wells without rubbing. I have about 7" of upward travel is my guess (not measured, just eyeballed).

I checked the Rancho RS9000 shock settings, and the fronts were set to the mid-point, but the rears were cranked as firm as they'll go. Could be that they've just too warn (though less than 6K miles on them?), due to all the off road use this truck has seen (viturally all the miles has been off roading)

I'm going to try a set of stiffer springs in the near future. Just need to research and see what springs are appropriate for me.

 

[outdoors]

Here's a run I went on with a group I am still a part of..
I usually air down to at least 13 psi, I can go down to 9 psi.
It really depends on the wheelin' conditions with traction being one of the biggest things..
My rig and comments of it (2) are 3/4's of the way down the page... I like to see what I can get away with and believe in taking your time choosing your placement route...
http://www.naxja.org/forum/showthread.php?t=955307&page=3