[Hattrick]

08 GXP with ZOK springs, swaybars, and Koni yellow adjustable shocks, set on soft. I have 265/35/19 RE11s on the front also. Ride is way too stiff, If i switch back to a GXP swaybar would it help, or am i looking at diff spring combo or coilovers?

 

[kwtoxman]

19 REs on all that are really going to be dedicated (nice way of saying hard). Going back to the stock swaybar will definitely help if you have it. Softer springs and tires will help as well. Think of it as a trifecta, so to speak.

 

[Hattrick]

Yes, ill try the swaybar with the softer bushings first. Basically did it all at once. Big change. Thx.

 

[wspohn]

Ride is way too stiff, If i switch back to a GXP swaybar would it help,

Not at all. A sway bar has zero effect on how stiff the car is in bounce and rebound, that is all the springs and shocks.

 

[TomatoSoup]

:agree: ... and the 19" wheels (and thus, lower sidewalls) are really not helping. If you still have your OEM 18's, try swapping them back.

 

[kwtoxman]

Not at all. A sway bar has zero effect on how stiff the car is in bounce and rebound, that is all the springs and shocks.

Since the world is riddled with bumps that affect one corner of the car, yes, a softer sway bar will make the suspension act softer.



How sway bars work

A sway bar couples the suspensions on each side to each other, *AND* relative
to the chassis. If you could put the car up on a lift and actually compress
the suspension on one side by hand, then a sway bar makes the compression of one
side also try to compress the suspension on the other....

A sway bar effectively increases the spring rate on whichever side
is compressed the MOST. If the sway bar were absolutely solid with no
twist so there's a 100% coupling between each side then
an attempt to compress one spring actually becomes an attempt to
compress both springs. It doubles the spring rate. If the bar has some
twist, then it may only increase the spring rate by say 50% on whichever side
is compressed the most.

So you're driving down the road and you go over
a bump that goes across the entire lane. The sway bar
does nothing. Both sides compress normally. You go around a
corner and the chassis starts to lean and compress the outside
suspension and now it's as though you have a bigger spring
out there, so the car remains more level. That's the good part.
Here's the bad part. You hit a bump with only one side, and it
behaves the same way, as though you have a stiffer spring,
so you feel uneven bumps more. You feel it crossing anything
diagonally as well, such as coming into or out of a parking lot
or driveway curb.

http://en.wikipedia.org/wiki/Sway_bar

Drawbacks - Because an anti-roll bar connects wheels on the opposite sides of the vehicle together, the bar will transmit the force of one-wheel bumps to the opposite wheel. On rough or broken pavement, anti-roll bars can produce jarring, side-to-side body motions.., which increase in severity with the diameter and stiffness of the sway bars.

 

[TomatoSoup]

Sigh. . .

 

[LatinVenom]

Another question would be as follows:
What is your tire pressure set at?.
Although the posted article have some merit, I believe in his case the Konis are probably contributing to what he is experiencing, provided the tires pressure is set correctly.

 

[Hattrick]

I had to lower tire pressures to low 20 psi to get any compliant ride. Originally had them at 32 front. What seems weird is the back end is much less stiff . Anyone using zok springs out back have this kind of difference? There is a little more sidewall out back at 285/40/19. Thx.

 

[Hattrick]

Switching back to the GXP swaybar made quite a diff. with 32 psi. all around. One correction to previous post, rear tire size is 285/35/19. Im selling the ZOK front bar if anyone interested. Ill post it asap, thx.

 

[Hattrick]

Here's a heads up if anyone is planning this spring , shock and wheel, tire combo. I changed back to the way less beefy gxp swaybar. it totally transformed the front end ride. just compliant enough for street driving. And with 32 psi tire pressure. I really didn't think it would make such a big diff.

 

[kwtoxman]

Thx Hattrick for the feedback, both initially and more importantly over time. Very helpful, and some vindication.

I definitely agree that springs and shocks have most of the input to the suspension characteristics. But when everything is changed (springs, shocks, swaybars), and the vehicle becomes too stiff to suit one's preferences, do the simple changes first. It saves money and time, and in the OP's case, the issue was resolved.

 

[g8gt09]

what did you expect to happen when you installed ZOK suspension coponents? That is was going to ride softer?

 

[Hattrick]

No, def not softer, but compared to the rear of the car the front end felt like the springs werent moving at all. Darting and jumping about. The rear also has ZOK springs and swaybar plus a probeam and i wouldnt even classify the ride as stiff. Im thinking know the best suspension bang for the buck is a good set of shocks. I never liked the stock Bilsteins much.