Rear Suspension Sitting Lower Than Front.

[Zeuseidon]

Hey guys... I have recently installed a set of Bilstiein B8's paired with Swift Spec - R Springs, and SPL Rear LCA.

** EDIT - I've elaborated my description because people were having a hard time comprehending the numbers**

The rears are sitting about 1/8" lower than the front. As opposed to the roughly 1/8" higher than the front like it should be. For a total of about 1/4" lower than it should be. This is also accounting for the "stock" numbers that read 1/4" higher in the back were wrong on my particular build and assuming they were square (as I didn't measure my stock numbers). So the rear could be as much as 1/2" lower than it should be sitting.

I have checked spring perches to see if they are sitting correctly, checked to make sure I didn't install the front springs in the back (which from what I can tell wouldn't even be possible since the spring diameters are different), and can't seem to figure out why it's sitting that way.

I have checked with the supplier and they checked some pictures out of the install and said everything seems okay and they do not know why they are sitting that way.

I thought maybe the front springs needed some time to "break in," but its been roughly 1k miles and still the same measurements.

Any suggestions are much appreciated.

[skylinekin]

Just a thought.... what you are seeing could be the result of "natural" rear negative camber gain being greater than front camber gain from lowering the car. More negative camber will lower the ride height.
I am assuming you have OEM rear lower control arms. Maybe some adjustable rear arms and taking out some rear camber would level things out for the small amount you are experiencing.

[Scrappydoo]

Checked the trunk?

Seriously though - maybe check with the people you bought them from?

[Zeuseidon]

Forgot to add in a couple things! I do have SPL Rear Lower Control arms as well. I also was talking with the company I purchased the package from and communications seemed to stop once I checked everything they asked me too.

Even sent pictures of the LCA's to make sure they were installed correctly.

Also I was comparing the Stock wheel/fender measurements to what mine are currently. That's where I was getting the measurements from.

[solidONE]

So it's is sitting 1/8" lower in the rear relative to stock AND SPC rear lower control arms?

One way you can check whether if the rear springs are too short or if it's the RLCA mounting holes are different to factory (most likely case, IMO), is to mount the factory RLCA and check the height again. If it sit at the same height then you know it's the springs. If the heights changes then you will have narrowed it down to the SPL arms as the cause for the rear sitting lower than it should. Shouldnt take more than 30 minutes to do each time.

[Zeuseidon]

Originally Posted by solidONE

So it's is sitting 1/8" lower in the rear relative to stock AND SPC rear lower control arms?

One way you can check whether if the rear springs are too short or if it's the RLCA mounting holes are different to factory (most likely case, IMO), is to mount the factory RLCA and check the height again. If it sit at the same height then you know it's the springs. If the heights changes then you will have narrowed it down to the SPL arms as the cause for the rear sitting lower than it should. Shouldnt take more than 30 minutes to do each time.

That's actually a good idea... I have a new exhaust coming this week, so I'll check then when I'm down there...

Also looks like there's three mounting holes for the SPL arms. If I put it to the outer most it should raise the ride height in the back.

Just trying to make sure I'm not compensating for a faulty part.

[Tcoat]

You are really worried about a 1/8th difference? How did you even measure a difference that small?

[strat61caster]

Did you re-install the rubber thingy at the top of the rear springs? That'd probably be about 1/8" difference if you forgot it. Did they come with new bumpstops or were you supposed to re-use OE?

That's about all I can think of to raise the rear up. You could add additional rubber gasketing between the spring and the perches (upper would be easier imo) or maybe add spacers to the bump stop to have it engage sooner, basically increasing the rear stiffness.

Originally Posted by Tcoat

You are really worried about a 1/8th difference? How did you even measure a difference that small?

A tape measure, not rocket science.

But I concur, if it's legitimately 1/8" I wouldn't sweat it, changing the ride height to have front or rear higher or lower is a common way to tune balance, nothing will be hurt aside from the OP's OCD.

[Zeuseidon]

Originally Posted by Tcoat

You are really worried about a 1/8th difference? How did you even measure a difference that small?

Lol, yes I measured.

An 1/8 of an inch lower than the front, is roughly 1/4 of an inch lower than it SHOULD sit. Not hard to notice wheel gap imo.

But I noticed because I had a tire rub ring on my rear tires after an Autox event.

[Tcoat]

Originally Posted by strat61caster

Did you re-install the rubber thingy at the top of the rear springs? That'd probably be about 1/8" difference if you forgot it. Did they come with new bumpstops or were you supposed to re-use OE?

That's about all I can think of to raise the rear up. You could add additional rubber gasketing between the spring and the perches (upper would be easier imo) or maybe add spacers to the bump stop to have it engage sooner, basically increasing the rear stiffness.



A tape measure, not rocket science.

.

On a perfectly level glass surface? You can get more that a 1/8th of an inch variation on any other surface. It was a rhetorical question intended too point out how ludicrous worrying about a bloody 1/8th of an inch is. Shit just put more or less fuel in the tank and you can vary the rear by an 1/8th of an inch.

[Zeuseidon]

Originally Posted by strat61caster

Did you re-install the rubber thingy at the top of the rear springs? That'd probably be about 1/8" difference if you forgot it. Did they come with new bumpstops or were you supposed to re-use OE?

That's about all I can think of to raise the rear up. You could add additional rubber gasketing between the spring and the perches (upper would be easier imo) or maybe add spacers to the bump stop to have it engage sooner, basically increasing the rear stiffness.



A tape measure, not rocket science.

But I concur, if it's legitimately 1/8" I wouldn't sweat it, changing the ride height to have front or rear higher or lower is a common way to tune balance, nothing will be hurt aside from the OP's OCD.

The Bilsteins have internal bumpstops. No need to use them. Everything else was reinstalled.

And yes a lot of it is my OCD. But I bought the Spec R springs over the Tarmac springs because of the spring rates mainly, and the rake secondarily. Not the biggest issue if this is just the way they'll sit. Just want to make sure nothing's "faulty."

[strat61caster]

Originally Posted by Zeuseidon

The Bilsteins have internal bumpstops. No need to use them. Everything else was reinstalled.

And yes a lot of it is my OCD. But I bought the Spec R springs over the Tarmac springs because of the spring rates mainly, and the rake secondarily. Not the biggest issue if this is just the way they'll sit. Just want to make sure nothing's "faulty."

Oh, missed that you were using Bilsteins.

Um the rears do not have internal bumpstops, you need to re-use the OE bumpstops on the rear and that's probably why it's sitting lower.

Edit: Also I reccommend putting the little bushing shown in the picture here on top of the top hat, not underneath, I had it under and I believe it was causing the damper to bottom out prematurely.

[Zeuseidon]

Originally Posted by Tcoat

On a perfectly level glass surface? You can get more that a 1/8th of an inch variation on any other surface. It was a rhetorical question intended top point out how ludicrous worrying about a bloody 1/8th of an inch is. Shit just put more or less fuel in the tank ad you can vary the rear by an 1/8th of an inch.

Haha TCoat, I know you like to stir pots. But I don't think a total roughly 1/4 inch is "nothing" and OCD.

If my post about height differences offends you, you could have simply scrolled past.

[Zeuseidon]

Originally Posted by strat61caster

Oh, missed that you were using Bilsteins.

Um the rears do not have internal bumpstops, you need to re-use the OE bumpstops on the rear and that's probably why it's sitting lower.

Edit: Also I reccommend putting the little bushing shown in the picture here on top of the top hat, not underneath, I had it under and I believe it was causing the damper to bottom out prematurely.

Damn... I was told by a couple sources they did. Oh well.

If that's the case, would the bumpstop actually effect static height?
Seems to me they would only effect compressd height?