"Floating" feeling in the rear after all new poly bushings

[ScHpAnKy]

Did the subframe, Diff, and RTABs in the iX along with poly offset CABs in the front - but I'm running into a wierd issue, and that's that the rear end feels like it's "floating" all over the place.

New bushings, new springs, brand new shocks, brand new sway bushings and endlinks all around - the diff is solid in it's mount, the subframe bushings are exactly the right height, but it feels like the rear end is completely disconnected from the car, so much so that a sweeping corner makes the car feel like the body is swinging away from the road and the wheels feel planted. Over bumpy roads the steering is all over the place as a result.

Some research indicates that the rtab brackets may not be tightened down entirely, I haven't had a chance to check it out - but would that be my issue?
If the RTABs are cranked down, what about the differential? Is it possible that the through-bolt would cause this issue when everything else is tightened down?

[jlevie]

If nothing in the rear is loose, it sounds to me like this is probably a spring rate/height problem that is resulting in too little weight on the rear wheels.

[LJ851]

It is not possible to change the weight on one end or the other of a vehicle with a few inches of ride height or spring rate. Not an amount more than splitting hairs anyway.

Did you reset your front toe after the offset CABs ?

[tinkerputzer]

Did you connect the rear sway bar?

[jlevie]

It is not possible to change the weight on one end or the other of a vehicle with a few inches of ride height or spring rate. Not an amount more than splitting hairs anyway.

Well, not really true. I can make a noticeable change in handling quality by just fiddling with the spring pads on my Spec E30. Twiddling with ride height is powerful stuff. And when you throw different springs into the mix...

[LJ851]

Well, not really true. I can make a noticeable change in handling quality by just fiddling with the spring pads on my Spec E30. Twiddling with ride height is powerful stuff. And when you throw different springs into the mix...

I didn't say it would not affect handling, i said it would not change weight balance. I stand by that statement.

[digger]

I didn't say it would not affect handling, i said it would not change weight balance. I stand by that statement.

laws of physics are a bitch;)

[ScHpAnKy]

If nothing in the rear is loose, it sounds to me like this is probably a spring rate/height problem that is resulting in too little weight on the rear wheels.

I don't think it's a problem with rear weight - I have a fuel cell from a previous owner where the spare was, and no gas tank under the car. Not ideal, but I'm working around it.

It is not possible to change the weight on one end or the other of a vehicle with a few inches of ride height or spring rate. Not an amount more than splitting hairs anyway.

Did you reset your front toe after the offset CABs ?

It's worth a shot, I guess, but the front of the car feels solid and overall just perfect, just the rear is flying around all over the place.. over bumps the rear does the same affect that a solid axle car would exhibit in addition to a linear "swing" going as low as 40mph through a sweeping curve

Did you connect the rear sway bar?

With all new hardware and bushings, yes

[ELVA164]

Something is wrong in the rear alignment-wise in my opinion. Either that or the rear is too stiff by a good amount. Perhaps it was stiff before but the softer bushings were able to dampen the effect some? What do you mean "the rear does the same effect that a solid axle car would exhibit?"

[ScHpAnKy]

The tundra @ 1:19 in this video is the feeling that I'm getting over bumpy roads:

[LJ851]

Why don't you tell us what parts you put on? What are the new springs, shocks, etc?

[ScHpAnKy]

Why don't you tell us what parts you put on? What are the new springs, shocks, etc?

h&r sports / billy sports
oem sway brackets/lonks/bushes
powerflex cabs, street hardness
revshift street hardness rtabs, dif, and subframe bushings
oem control arms/tie rods
NTB alignment

[Liquidity]

Just sounds like you need an alignment.

[LJ851]

NTB alignment

Just sounds like you need an alignment.

Assuming everything is bolted up tight, the only thing i can think of right now is that you have massive stiction in the poly rear trailing arm bushes that don't allow the wheel to stay planted on the road causing uneven/sketchy grip.

[ScHpAnKy]

Assuming everything is bolted up tight, the only thing i can think of right now is that you have massive stiction in the poly rear trailing arm bushes that don't allow the wheel to stay planted on the road causing uneven/sketchy grip.

So i went through the car with a fine tooth comb because after spending hundreds of dollars in repairs on the car, Ive only driven it four days since january just gettin it to the same state as my last car. It's frustrating to say the least.

Last weekend I put in a new steering coupler and knuckle and set it up to be solid mount to be certain there was no "give" in tbe front of the car.
Tested my steering rack afterwards, solid as a rock but the issue persists :(

So, per your recommendation I took a jack to both trailing arms to observe movement - looks great, full range of movement.

I did notice, however, that the differential mounting tab has a bend in it with roughly 1in space between the bushing and bolt head when loosened up. Is the tab supposed to stand straight up and down without any bend? Im going to put a spacer in this weekend and see if it improves, but Im really close to just parting the car out at this point.