Bumpy ride with Eibach sway bars

[pibirdman]

I installed the Eibach front and rear sway bars and the rear is really bumpy. Before the install the ride was not too bad even with all the suspension mods. Any ideas?

My suspension mods:
Cobra Jet f/r springs
Tokico Blue f/r shocks/struts
J&M upper and lower control arms
BMR panhard bar
Drake front adjustable end links
Eibach f/r sway bars
Ford Racing stut mounts

 

[mac10chap]

You're in Houston bro. 90% of my daily driving is bumpy here. I dont see how sway bars would make your ride bumpier though.

 

[DRock]

sway bars should of made the ride better if anything

 

[Justin_H]

Stiffer anti-roll bars will make the ride worse over one wheel bumps- it's just the way they work. If you go straight over a speed bump, it should be exactly the same as before the bars. If you go a little crooked, it should rock you around more side to side.

The only way they'll make the ride better is if you go smaller. If the bar isn't a lot bigger, make sure you greased the bushings well, and check that nothing is contacting a hard part. Disconnect both ends and see how smoothly it rotates- maybe it's binding excessively. If it's rougher going straight over a speed bump, something isn't moving freely.

 

[Kobie]

I switched to the Strano sway bars, set on full soft, and my ride and handling improved greatly over my previous setup.

 

[Davenow]

Swaybars definitely can and usually DO make the ride worse over bumps.

Why?

You are tieing the wheels together. The stiffer that connection, the less independant those wheel can move of each other. Which means if you hit a bump on your left wheel, it will transfer some of that shock to the right wheel. Which means that bump now is overcoming not just the spring and damper on the left, but a little of the right. They wont make any difference over bumps that BOTH wheels hit at the same time, but they will make a difference (in terms of a stiffer ride) on bumpy roads that have random bumps all over.

That is grossly oversimplifying it, but it gets the point and why out there.

But it has nothing to do with Eibach and everything to do with stiffer bars.

Anyone that tells you they went to a stiffer bar and said the car rides smoother, is kidding themselves. It is physically/mechanically impossible. Want to feel a cushy ride over bumps? Disconnect your swaybar and see how much smoother it is. What does that tell you about going to a stiffer bar than stock?

 

[Sleeper_08]

Justin_H & Davenow

Thank you for the valiant efforts using science and physics to battle the placebo effect.

I find it amusing when people say they install a certain relatively insignificant part and the result is "the car now handles like it is on rails". Especially when they are driving on the street and for everyone's sake should be driving nowhere the limits of the car even as it comes from the factory.

If you want your car to handle better then my suggestions are;
1) get the best high performance tires and light weight wheels you can afford and can live with on the street. Wide tires can tramline and be annoying. Sticky tires wear out faster
2) a set of Koni Yellows
3) the correct set of springs for your requirements
4) the proper set of Sam Strano's 3 way adjustable sway bars for your requirements
5) Steeda HD front strut mounts

This assumes you have also upgraded the brakes with DOT4 fluid changed annually, proper pads for how you drive the car on the track, Brembo front brakes and, if required for the tracks you run, front brake cooling.

If after you install the springs the axle is too far off center then get an adjustable panhard bar to center it.

Then spend as much money as you can afford learning to drive the car from a good instructor on a road course.

At some point you might want to upgrade the panhard bar to a FAYS2 Watt's link.

If your really get addicted then you will need a set of track only wheels and tires. R compounds are way too much fun but first learn to drive on street tires.

 

[Norm Peterson]

I installed the Eibach front and rear sway bars and the rear is really bumpy. Before the install the ride was not too bad even with all the suspension mods. Any ideas?

Since swapping the bars in, have you been driving any faster?

Separate from the fact that stiffer bars will increase the "stiff-leggedness" of the ride going over one-wheel bumps, the speed at which you hit them also matters (and would tend to increase the amount of bump damping force coming through the shocks).


Another way of looking at the bars' effect on one wheel bumps is to realize that bumping just one wheel up puts the axle into a roll situation relative to the chassis - and it's precisely this relative roll that stiffer sta-bars are going to resist with greater forces.

That also means that you should expect to feel the effect of bumps that are hitting both wheels at almost but not precisely the same time . . . more than you did before. Chances are that many of the bumps you hit fall into this category.


Other than your Mustang, what other cars/vehicles do you have as a basis for comparing ride quality? The bar change might feel greater if the rest of your experience is in vehicles having smoother/softer ride motions.


Norm

 

[kevinatfms]

^ could they increase spring rate? i would think so if they are mismatched to a certain spring type....

added spring rate on stiff springs=bumpy ride?

 

[Norm Peterson]

In one wheel bump mode, a bar absolutely does add wheel rate at the wheel being bumped upward (regardless of whatever rate the springs themselves happen to have). A stiffer bar simply adds more.


Norm

 

[Sam Strano]

FWIW, the suspension posted is real mix-mash of parts.

Cobra Jet springs, as in drag type springs? Well those and bars aren't usually a good match. Also Eibach has more than one rear bar, and if it's a huge one that's not helping. And these endlinks you have, are adjustable, yes? Well if you have them adjusted wrong--that won't help either. Add in any sort of binding like the bushings aren't well lubed and you have a lot reasons why that aren't necessarily the "fault" of the bars.

I gotta say, a rough ride is not a complaint I get on my bars. And I sell Eibach too, unless you have some bar the size of my forearm you have something else going on.