[1nicerAnd1]

Hi All!
I despair about the conversion of my car.
My G87 was recently converted to KW HAS and Edelweiss rims (10.5x19 - 275/35/19 & 11x20 - 285/30/20 PS4S) and the ride comfort is unbelievably bad.
The car rocks with every slight bump and I rock from left to right in the car.
The lowering is discreet and not maximum on the ground...
Who has similar experiences or an idea what the problem could be?
It drives as if the suspension is permanently set to sport plus. strangely enough, hard bumps are absorbed relatively well

Thanks for your help!!

[Carefree]

Have you experimented with different tire pressures?
Just a thought…………..

[DomMuc]

what is the car doing with OEM Tyres and Rims ?!

[daddyjaxx]

I have PS4S, too, and changing the tire pressures makes a noticeable difference in drive quality. For example, for two months, I ran 38 psi (cold) in the rear and 36 psi (cold) in the front. Then, I changed all the tire pressures to 34 psi (cold). This small change made highway driving less comfortable (harsher ride and increased "felt" road imperfections). However, during spirited driving, high-speed turn-in felt more confidence-inspiring.

[M_Power Rob]

Bouncing or stiffness/harshness, yes (though I dont have those issues with the MP HAS) but I dont get the "rock from left to right" description.

I know you are sticking with the oem tires but the may be one size small for the rim sizes.

[chris719]

Lowering springs and HAS always degrade ride quality. Shorter springs mean less travel, and to make sure you stay out of the bump stops and manage travel, the shorter spring needs to be quite a bit stiffer.

[1nicerAnd1]

I have tried different tire pressures in a range from 32 psi to 42 psi. It changes the driving experience but does not eliminate the problem.

I know that lowering always has an effect on ride quality but my problem is not heavy bumps, its the small road bumps that that cause the car to sway unnecessarily..

It feels like its locked in sport plus for damping.
But I do not get any error messages

[1nicerAnd1]

Originally Posted by DomMuc

what is the car doing with OEM Tyres and Rims ?!

if I don't find the reason I will try it with my winters on OEM wheels

[ZPD]

Are you sure that you reconnected your sway bar?

[JCoR]

Originally Posted by ZPD

Are you sure that you reconnected your sway bar?

Yeah sounds like potential problem with the install. I have KW HAS and don't have any issues.

[Ravenseal]

You probably need to revisit the installation of the HAS kit, as well as the alignment and ride height. Make sure everything is mounted correctly and torqued to spec.

[1nicerAnd1]

Short update:
The whole installation got checked and everything on mechanical side should be fine.
I have now changed back to winters on original wheels and … it’s better
Not really good but significantly better….
Don’t know how to handle that information

[Tag]

Originally Posted by 1nicerAnd1

Short update:
The whole installation got checked and everything on mechanical side should be fine.
I have now changed back to winters on original wheels and … it’s better
Not really good but significantly better….
Don’t know how to handle that information

Check the scrub radius on your summer setup. You can use a wheel/tire calc like this one and compare it to stock which will be your baseline. You already posted the figures for your summer wheels and tires. Only other figures you need are the wheel offsets for F/R.

[Ravenseal]

Originally Posted by 1nicerAnd1

Short update:
The whole installation got checked and everything on mechanical side should be fine.
I have now changed back to winters on original wheels and … it’s better
Not really good but significantly better….
Don’t know how to handle that information

Unironically, you probably need wider tires. You're pushing the lower limits of the recommended sizing for your rims. If I had a 10.5/11.0 setup I'd be running 285 or 295 front and 295 or 305 rears.

[1nicerAnd1]

Originally Posted by Ravenseal

Unironically, you probably need wider tires. You're pushing the lower limits of the recommended sizing for your rims. If I had a 10.5/11.0 setup I'd be running 285 or 295 front and 295 or 305 rears.

Yes I will have to think about it…
But then it should be fine with winters and it wasn’t. It was a bit softer and better but the rear end still moved too much. The car always rocks/swings up/left to right.

[1nicerAnd1]

Here some images (love the look and yes it’s not clean :P )

[DailyDownshift]

I have horrible roads downtown where I'm at and experience the left to right movement as well with KW HAS. A HAS kit is going to make bumps feel more shitty, no way around that fact. I just suck it up and tell myself its a race car lol

[1nicerAnd1]

Originally Posted by DailyDownshift

I have horrible roads downtown where I'm at and experience the left to right movement as well with KW HAS. A HAS kit is going to make bumps feel more shitty, no way around that fact. I just suck it up and tell myself its a race car lol

Not what I wanted to hear! 😅
I have talked to KW and many dealers in advance and they praised their product - now they have to find a solution…

[DailyDownshift]

Originally Posted by 1nicerAnd1

Not what I wanted to hear! 😅
I have talked to KW and many dealers in advance and they praised their product - now they have to find a solution…

Well then you've been mislead. It's going to be a harsher ride but I still don't think it's brutal, just depends on the type of roads you have around you. If you have nice roads then you probably wont experience a deterioration in ride quality at all in exchange for a stiffer, more sporty feel. Gotta live with it, otherwise you have that horrifying stock ride height look.

[Sleeper]

Age old case of not enough dampening and not enough travel when paired with lowering springs. The mitigation is always higher spring rates to avoid hammering into the bump stops constantly, so ride quality will suffer, as will dynamics when the car hits weird/uneven surfaces. It comes with the territory.

The stock dampers were designed around the stock springs (at the 4x4 ride height). Reducing the ride height with anything but a cup kit or full coilover solution is going to have compromises.

For me, I didn’t even take delivery of my car until the KW HAS was installed, and wound all the way down . I’m good with the compromise!

[1nicerAnd1]

Originally Posted by Sleeper

Age old case of not enough dampening and not enough travel when paired with lowering springs. The mitigation is always higher spring rates to avoid hammering into the bump stops constantly, so ride quality will suffer, as will dynamics when the car hits weird/uneven surfaces. It comes with the territory.

The stock dampers were designed around the stock springs (at the 4x4 ride height). Reducing the ride height with anything but a cup kit or full coilover solution is going to have compromises.

For me, I didn’t even take delivery of my car until the KW HAS was installed, and wound all the way down . I’m good with the compromise!

Yes, I get it and I knew about compromises but the ride quality atm isn't even a compromise atm...let's see what the guy at the shop has to say today/tomorrow.

Are you riding on standard tire/wheel combination?

[Sleeper]

Originally Posted by 1nicerAnd1

Yes, I get it and I knew about compromises but the ride quality atm isn't even a compromise atm...let's see what the guy at the shop has to say today/tomorrow.

Are you riding on standard tire/wheel combination?

If it’s really crashy and unsettled, sounds like something might be off (although hard to mess up the install).

Sorry if I missed it, but did you have the car aligned after install? If so, can you post your settings?

And yes, I’m on stock wheels and MPS4S tires (with 18/15mm spacers).