suspension tuning Q

Ok, so this isn't "tuning" like I'm on coilovers or building a JS rig, but...
I'm running ZJ V8 coils & a 5/8" spacer up front, Upcountry leaves & a 1.5" shackle in rear, JK (black) shocks all around.
Going straight over bumps, I like how it handles just fine. Could even go stiffer without complaints.
Over uneven bumps / potholes, though, it rattles me side to side. Irritating - don't like driving the rig.
I have the stock 1" bar with poly bushings at the frame and end links.

So, what is my best bet to keep her riding level side to side? Rear sway bar? Stiffer shocks? Shackle relocation?

My shackle angle is 90 degrees, so I want to fix that anyway, but where should the first bucks go towards fixing the stability?

How's the sway bar in the front?

Stock, intact & with decent bushings. Could try freshening them up, see if that makes a difference.
I may also get a ZJ bar at the JY... already have bushings for the 28 mm...
any other ideas?

Sounds like you want to remove the anti-sway bar so that the suspension can absorb the impact on one side without trying to spread the force through the bar.

It sounds like you are describing death wobble i would check your track bar and the condition of all your tie rod ends, you probly need a good adjustable track bar i had the same issue until i replaced my track bar.

Well, shackle relocation brackets will help.. but also more lift. Boomerang shackles will help.

yossarian19 said:

Ok, so this isn't "tuning" like I'm on coilovers or building a JS rig, but...
I'm running ZJ V8 coils & a 5/8" spacer up front, Upcountry leaves & a 1.5" shackle in rear, JK (black) shocks all around.
Going straight over bumps, I like how it handles just fine. Could even go stiffer without complaints.
Over uneven bumps / potholes, though, it rattles me side to side. Irritating - don't like driving the rig.
I have the stock 1" bar with poly bushings at the frame and end links.

So, what is my best bet to keep her riding level side to side? Rear sway bar? Stiffer shocks? Shackle relocation?

My shackle angle is 90 degrees, so I want to fix that anyway, but where should the first bucks go towards fixing the stability?

Click to expand...

If you are getting thrown side to side then I would think running wider wheels, like 4" or 3.75" backspaced cragers or wheel spacers would help. It adds stability. My rig is lifted 4.5" with a rather firm suspension and I have stock 16's and 32" tires. I'm being rocked back and forth all the time because of the narrow width combined with added height. It did not do this when I had 4" backspaced cragers and 31's. When I hit a dip or pothole on the passenger side, I get tossed that way a little and it rocks back. It gets annoying during a long ride, I know.

Lowering my tire pressure to the lowest I can go without sacrificing tire wear helps just a little because the tire will absorb the bumps better. Downside to that is loss in MPG.

This is my narrow/tall setup that rocks back and forth:



This is my wide/tall setup that had no side to side instability:

Y'know, I'd forgotten about it, but for the 2 weeks I ran wheel spacers it did feel a lot better. I've been hoping to avoid new wheels ($$) but I think I'm back in the market.
Hell, I might need them for axle plans anyway. Thanks for the advice!

yossarian19 said:

Y'know, I'd forgotten about it, but for the 2 weeks I ran wheel spacers it did feel a lot better. I've been hoping to avoid new wheels ($$) but I think I'm back in the market.
Hell, I might need them for axle plans anyway. Thanks for the advice!

Click to expand...

yeah it's crazy how 2" of extra width can make a huge difference. I love my current wheels/tires but I hate the rocking so I might be swapping the wheels out for some 16" cragers and using 4" backspacing. Just gotta keep em under the flares or PA cops will have a hissy fit.

Hmm.
Stock, the Cherokee is 64" tall and 70" wide (with tires). Height = %91 of width. It's pretty stable.
Lifted 3" w/ 31s, 68.5" tall & 71.5" wide. Height = %95 of width. This is my rig, and I say "not that stable". 4% makes a difference!
Same lift & tires with 4" BS wheels, we get
68.5" tall x 74" wide, Height = %92.5.

Just a few numbers to play with, guesstimate stability of mods (if you are keeping vaguely stockish spring rates & shock valving, anyway)

I don't mean to jack your thread but I believe I'm having the same issue. My jeep feels like it's on the verge of death wobble all the time is that what it feels like. I'm trying to fix mine also. Just got new tie rod ends and all new ball joints and I'm trying to get my track bar bracket welded so it stops coming loose. I'm only running a three inch lift up front with lower arms and stock leafs kinda have the prerunner look. Till I can lift the rear back up.