Control arm bushing comparison

[boxer246]

Before I get blasted....I read through as many previous posts on control arm bushings and couldn't really find the info I'm looking for.

I'm a little confused on front control arm theory......it seems there is two different options that to me, sort of contradict each other.

On the one hand you have the OEM replacement rubber bushings, offered by several different manufacturers, each one claiming their superiority. In watching videos and reading material on rubber bushing removal and installation, it seems as though the amount of force required to install them, and subsequently rotate the front bushing mount to its proper angle, is such that when installed on the car, the control arm would have significant resistance to rotation around its longitudinal axis.

On the other hand you have several different "low friction" bushing options, even "Self aligning" type offered by a couple different manufacturers. Clearly, the idea here is to place the control arm in a position which it is allowed to rotate along its longitudinal axis as freely as possible.

Now in my simple way of thinking, one would ideally want the lowest friction type which would allow the torsion bar and shock absorber to do their jobs un-hindered. To have additional friction would just be absolutely working against the job of the shock and torsion bar. Using a comparison to a motorcycle, if one has the front forks out of alignment such that there is significant "stiction" on the fork sliders, those forks will work poorly.....and it is a very noticable difference between those and ones that are exactly parallel and true.

So my question is, despite a arguable difference in ride quality (OEM rubber bushings theoretically more comfortable), is there a real difference in the low friction type allowing the suspension to work properly? I.E, is the extra drag/friction provided by the stock bushings noticeable in comparison?

I have come to the realization that my control arms are out of alignment, and are both sticking significantly.....they creak and move in a jerky fashion, and the ride quality is absolutely horrible, despite brand new Bilstein HD's on all 4 corners. In fact the front Bilsteins accentuated the problem. So weather I choose OEM Rubber, or expensive low friction type, I know for sure I need the self-aligning kit offered, as that is my real problem I believe.

[DRACO A5OG]

The aftermarket, even supposed OEM rubber ones will not stand up like the original factory ones, over a short period of time they may squeak go out of round. At least that is what my Netrix are doing in the rears.

I uped to Rebel racing fronts and found the ride to be stiffer but handling is outstanding, No noises after years of daily driving and occasional AX/DE. I highly recommend them caveat, make certain your frame is straight and Rebel has zero tolerance for a bent frame. My other option was the grease filled ones but I did not want to have another maintenance task, But I read other love them.

You may also consider uping the T bars while you are at it

[Flieger]

The rubber bushings operate with essentially zero friction. They do add spring rate however, since you are twisting the rubber. So on the one hand they are great. On the other hand, they allow the control arm to move around. This is good for taking the edge off of bumps, but can cause the handling to be a little less sharp or at least give you less grip due to radial compliance.

Porsche tried bushings much like the urethane ones you can get but found the stick-slip caused terrible handling so they went for the silentblocs.

The Rebel Racing ones are a different material and are much better at reducing friction than urethane is, and they are so thin that there is very little radial deflection. You also don't have to worry about grease attracting dirt like in other designs.

So, the aim of the aftermarket bushings is reducing the radial deflection (so as to provide better wheel control) while still providing adequately low friction. You can't make a rubber bushing too much thinner or else you won't have enough suspension travel.

One thing to note is that you loose spring rate with the non-rubber bushings, so it will make the ride softer in some ways. I think I heard that the rubber was the difference between a 19mm and 20mm torsion bar in front, so not insignificant.

[boxer246]

Thanks fellas that clears it up, and makes sense...that the rubber bushings do provide some degree of help in terms of spring rate to the torsion bars. So in a way the low friction bushings would soften the ride some due to a reduction of spring rate.

[tirwin]

From my reading, there seems to be another difference. I think the polybronze and similar technology bushings are trying to avoid pinching/binding along the torsion bar axis.