Front sway bar preload?

[VinceLA]

All,

Hoping to get some work done in that area. But throwing the above question out on the table first

Has any one found out if the front sway bar is preloaded from factory?

And if so, wondering if anyone has installed adjustable endlink?

Thanks.

[silverbrabus]

Preloaded? Is any car from factory? Preload is a corner-weighting racecar kind of thing, no?

Adjustable endlinks? Randy Zimmer was experimenting with bar mods in this thread: No more leaning in turns.

Sliding clamps would be even better.

[VinceLA]

Yes Randy and I speak on a regular basis. So I am aware of his mods. That modification he did has nothing do with with adjustable endlinks.

An adjustable endlink allows the length of the endlink to be varied, thus preventing preload when at rest. Ideally sway bar is not supposed to be preloaded at rest. A sway bar that is heavily preloaded can affect the rather "bumpiness" of the car when cornering or going over bumps.

[VinceLA]

Update:

Found some time to replace the driver's side of the endlink. Thing about using an adjustable endlink is that you only have to replace one side. The passenger's endlink is still a factory piece.




So what's the big deal with using this?

Ideally, the sway bar should not be loaded at rest from factory. Of course, the loading depends on the "wet" weight of the car, ie changing fluid level, driver's + passenger's weight. The goal is to get close to zero preload on the sway bar and even if it deviates from zero, let that deviation be small.

After installing the Eibach springs on factory 15", the front end will drop about an inch and with the fixed endlinks, that means the sway bar has to be preloaded at rest. The one way to test this is try to remove the endlink when the car is at rest with 4 wheels on the same level. Sounds impossible but it is in fact easier on the smart car. If the bolt on the endlink doesn't slide off the sway bar (or the side tab of the strut tower) easily, then yes you have a preload.

Now, the sway bar doesn't just prevent roll when cornering but it also prevents roll when one of front wheels hits a bump on a straight line. Reason being as the wheel moves up, the damper compresses along with the spring. This results in the strut tower attempting to move up, pulling up on the end link and thus on the sway bar. But of course the job of the sway bar is to minimize the movement of the strut tower. Another way to look at this is if the strut tower tries to move up, the job of the sway bar is to minimize that movement, thus "anti-sway".

After the installation, I drove around my usual routes, since I know where the road surface disturbances are. No hard data to back up but all I can say is that the bumps are less sharp and shocking on the front end.

Not a must-do mod but a good to have mod.

Here's a pic of the factory piece:

[gurps]

I'm planning on eventually getting a set of coil overs and lowering the car, so this sounds like an easy and cheap mod to me, but where to get the adjustable end link?

thanks
Tom

[silverbrabus]

Originally Posted by VinceLA

After installing the Eibach springs on factory 15", the front end will drop about an inch and with the fixed endlinks, that means the sway bar has to be preloaded at rest.

Don't claim to be a suspension expert, only going by personal observation, but unless I am missing something, this statement is incorrect.

From my experience, equal drop at both sides has no effect on sway preload, the bar will simply rotate at the body mounting points.

What will affect preload is unequal suspension height or weight distribution side-to side.

[VinceLA]

Originally Posted by gurps

I'm planning on eventually getting a set of coil overs and lowering the car, so this sounds like an easy and cheap mod to me, but where to get the adjustable end link?

thanks
Tom

I got mine from Ebay. Search for adjustable endlink. Or if you can try out:
Powergrid, Inc..

Originally Posted by silverbrabus

Don't claim to be a suspension expert, only going by personal observation, but unless I am missing something, this statement is incorrect.

From my experience, equal drop at both sides has no effect on sway preload, the bar will simply rotate at the body mounting points.

What will affect preload is unequal suspension height or weight distribution side-to side.

I am glad you pointed that out. My bad for making a vague statement.

But yes you're on the right track. So theoretically if each front spring/strut assembly are exactly the same and has the same exact compression travel, then yes if you have X preload prior then it should be X preload after.

Fact is no matter how you purchase a pair of springs and swap them in, both sides will have different drops. This coincides with what you stated as "...unequal suspension height". Added to that of course the driver's weight will definitely cause a greater difference. On the side note, the one company I know that actually sells springs in pairs within 10% rate is Hyperco. I didn't believe this until I scored 4 sets of springs from them and did a dyno myself.

The other thing about "equal drop" is as measured from what pt of reference. Equal spring travel may not be equal damper travel or fender height. Even if we somehow adjust everything such that fender heights are equal, I can assure you the spring/damper travel on both sides are not equal.

I think at some pt this discussion might bring in corner balancing...

[GHammerly]

So are you adjusting for zero preload with or without drivers weight?

[sunnyokanagan]

Found some time to replace the driver's side of the endlink. Thing about using an adjustable endlink is that you only have to replace one side. The passenger's endlink is still a factory piece.

I'm not sure what you mean here, Vince. Upgrading the one - driver's side - end-link is sufficient to dampen the sway bar action on both corners/sides?