Anyone interested in larger rear anti-sway bar

Count me in.

And FredWB, don't give up and don't take it personally. You are correct. It is what is commonly referred to as a "sway bar", "anti-sway bar" or "anti-roll bar". At least, I hope it is

 

OK this will be my last entry as sway bars are concerned. Once again the Prius has no rear sway bar. If anyone reading this goes to their window sticker and looks under mechanical and performance portion thereof they will see listed "torsion beam rear suspension". The bar that is being spoken of is the torsion beam. You cannot have a sway bar within an axle assembly. A sway bar has to have four mounting points: two to the suspension or axle and two to the frame or unibody, period. I have installed and modified enough of these to know what I am talking about, I do this for a living, and what you are talking about is not a sway bar on the rear. You can make this bar as large as you want, and unless you can connect it to the frame or unibody it is going to have no effect except to possibly change the camber on the rear wheels.

 

rutafox - This is not meant as flame bait. There is clearing a misunderstanding between us about terms. This is meant to spell out my understanding of the terms I am using. If I am using them incorrectly I would like to be educated.

The part in question is referred to by Toyota as the "Stabilizer Bar" which is functionally the same as a "sway bar" or "anti-roll bar."

According to Toyota, the Prius has a semi-independant torsion beam rear suspension with coil springs, strut-type hydraulic dampers and stabilizer bar. This is not the same as a "torsion bar" suspension.

A "torsion bar" suspension uses the bar as the spring to support the vehicle. If you remove the torsion bar, the vehicle can not be driven as the chassis will be sitting on the tires or wheels.

A "torsion beam" ties the right and left suspension trailing arms together to add strength. The torsion beam acts similar to a solid axle on some RWD car. The beam allows the rear suspension to be smaller, lighter and cheaper because it is simpler than a true independant suspension.

I was not able to find a picture of the 2004+ rear suspension, but here is the classic Prius suspension:

http://us1.webpublications.com.au/static/i...4/1458_14mg.jpg

It is not clear from this picture where the stabilizer bar attaches. If it is the way it looks in the picture then it would not reduce body roll, but if that is the case then why would Toyota put it on the vehicle. I guess I have to get underneath my car to make sure. Hope it stops raining soon.

Steve T









If it were, then FredWB would not be able to drive the vehicle without the bar, because the vehicle would be riding sitting on the tires.

 

That last sentence is obviously wrong, if you just examine the dynamics of the suspension movements. If the beam is attached to both trailing arms, and its axis of rotation is close to that of the suspension arms (or its center IS the axis of rotation), then the beam itself resists differential movement of the trailing arms through torsion, just like a sway bar. And the more resistant to torsion this beam is (through changes in size or cross section or material), the more resistant the suspension is to differential travel of the suspension arms.

This link shows a pretty good illustration of a torsion beam rear suspension. You can see here that when both wheels move together, the torsion beam has no effect, but when there is differential wheel movement (they don't move the exactly together), the beam will resist this differential movement, just like a sway bar. That's the whole purpose of the beam, to resist this differential movement. Without this beam, one wheel's travel will not affect the other, just like on a car with fully-independent suspension and no sway bar.

 

FredWB,
Good job, good initiative. Ignore the riff raff.
I'm interested, but need to know how big a deal to remove and install. Any special tools?

 

Just put my money down to get on the waiting list for a 2006. I think I'll keep after this thread and see how the first ones work, but might go in on the re-order if it looks like the upgrade works and is predictable.

I can attest to the efficacy of an aftermarket anti-sway bar on my current vehicle, a 1995 Impala SS. I've always liked vehicles that are extreme in some respect, but I'm not sure I can see myself looking for the spirited cornering in the Prius-to-be compared to my present car (which I'll trade).

 

Nice.. this is something i'm interested in. Put me down for the list as well, please.

 

This page describes what some suspension problems are and how to deal with it...

How Stuff Works describes what these "bars" are.

So what does the front sway bar look like?

 

any updates on the progress of the rear stabilizer bar? i'm definitely interested