Center Roll Adjuster-- Pros/Cons

[03.5MSP]

Roll Center Adjuster-- Pros/Cons

I was wondering if it is worth getting roll center adjusters which to my understanding is the same as a lower ball joint for the front control arm. I know hardrace sells a set for the protege and to my understanding for lowered vehicles they help bring the cars suspension geometry back towards the way it was designed. Also if I am not mistaken the CRA helps reduce the body roll, increased stability, sharper steering response, enhancing the cornering force.

However I am pretty sure I have heard of some CONS for running the CRA's. People have said that its not really the best way to adjust the cars geometry, as well as quality/durability...etc

So please post your experience knowledge about the CRA's and what you guys would recommend for lowered vehicles.

 

[43975]

subbing

 

[hornsfan10609]

I know on lowered Mustangs you run a bumpsteer kit to correct suspension geometry but i'm not familiar with a Center Roll Adjuster.

 

[NStone79]

Personally, I wouldn't mess with the roll center for a number of reasons. For starters I can't say I've heard of Roll Center Adjustment kit before, so I'm gonna go out on a limb and say they aren't very common so you probably should stay away. Second... Roll Center affects a lot of handling characteristics (body roll, roll couple, steering feel & response, weight distribution & tire loading, etc etc) A slight change could cause screwy and possibly dangerous handling. So it's best not to mess with that unless you are pretty well versed on suspension dynamics. At a minimum, you'd want to plot out all these specs on paper and figure out exactly what you are trying to accomplish. Also... the strut setup on our cars is not very adjustable and is far from ideal in many ways including it's effect on the roll center, specifically roll center dropping below ground level on compression.

 

[03.5MSP]

I know on lowered Mustangs you run a bumpsteer kit to correct suspension geometry but i'm not familiar with a Center Roll Adjuster.

Bumpsteer kits are the same as CRA's to my understanding, but have different name for some reason.

 

[03.5MSP]

Personally, I wouldn't mess with the roll center for a number of reasons. For starters I can't say I've heard of Roll Center Adjustment kit before, so I'm gonna go out on a limb and say they aren't very common so you probably should stay away. Second... Roll Center affects a lot of handling characteristics (body roll, roll couple, steering feel & response, weight distribution & tire loading, etc etc) A slight change could cause screwy and possibly dangerous handling. So it's best not to mess with that unless you are pretty well versed on suspension dynamics. At a minimum, you'd want to plot out all these specs on paper and figure out exactly what you are trying to accomplish. Also... the strut setup on our cars is not very adjustable and is far from ideal in many ways including it's effect on the roll center, specifically roll center dropping below ground level on compression.

The reason I ask is because when you significantly lower the car you throw off the stock suspension settings. The CRA's are suppose to compensate for the lowered ride height so that the suspension works like it was designed to.

 

[NStone79]

Ok, I think you might be talking about something different, possibly a camber correction kit or something similar? Here's a good diagram of instant/roll centers on a stock & lowered car also comparing a strut vs dbl wishbone setup

Also, I don't think a bump-steer kit is the same. Not sure what a bump-steer kit is, but I'm quite familiar with bump-steer and how to correct it (primarily from dealing with lifted trucks). In truck terms, when you lift something more than 3-5" the steering linkage is no longer parallel to the control arm geometry. Therefore as the suspension cycles, the steering linkage is pivoting on a different arc than the control arms. The end result is that the difference in the arc-path of the two manifests as the wheels can turn in and out. When you hit a bump; even though your holding the wheel straight the vehicle acts like you turned the wheel slightly on direction or another, hence the name "bump-steer".

 

[hornsfan10609]

Bumpsteer works the same whether lifting or lowering the suspension, as long as it's modified from stock it could use correcting. Look for a bumpsteer kit for our cars, I can't say that i've seen one but I haven't had my car very long either.
I'm pretty sure a bumpsteer kit consists of new tie rods for the steering rack that are adjustable.

 

[03.5MSP]

Here is what I found out doing some "research".

It doesn't come as much of a surprise that almost anything and everything for the MSP and proteges in general has to be custom made and suspension stuff is not any different.

The roll center adjusters are pretty much longer lower ball joints that replace the OEM pieces.
-The first benefit of this is that they change the angle of the LCA's back to OEM geometry.
-The second is that the roll center is also changed back to OEM geometry, which reduced body roll.
-The down side of the longer lower ball joints/ RCA's is that it is not really the ideal way of adjusting/correcting the roll center. Ideally it should be done at the point where the lower control arm mounts the the chassis, or fabricating a custom lower control arm which will allow for theses adjustments.

A bumpsteer kit/ adjusters replace the tie rod ends, with new pieces. The new pieces are longer in the distance from the knuckle to the tie rod, keeping the tie rod parallel to the ground when the car is lowered, allowing the suspension to rotate and function as designed.

 

[03.5MSP]

I got in contact with Hardrace and they advised me that the roll center adjuster kit is now discontinued. So it looks like the options now are custom control arms, or custom lower ball joints.

 

[HighSpeed]

get some camber plates or get a set of coilovers with them built in. camber plates will get you a ton of adjustment unless your wanting the body to sit on the ground.

 

[03.5MSP]

I don't think we are talking about the same thing here. I have AWR Coilovers and adjusting camber has never been an issue. Adjusting/ changing camber will have no impact on the cars roll center. The only way to adjust the roll center is to either get the roll center adjusters (longer lower ball joints) or custom fabricate both the control arms and the control arm mounting points.