The Hidden Cost of Sway Bars

Rupunzell

Bernice Loui
Happened across this video regarding anti-roll bars or "stability bars".
https://www.youtube.com/watch?v=WhWZ57baTOw

Stock exxe have none, some add them, some alter spring/damper rates as required. Overall, there is no one "perfect set up" only a mixed set of trade off to meet a limited set of conditions and chassis/driver requirements.

Yet the exxe chassis is tune-able and alterable enough to accommodate many variations in chassis set up.


Bernice
 
Bernice, I started to watch the video but the guy sort of mumble at the start and I got tired of looking at his mug. I have a feeling you could do a better job of explaining.
 
Yes, the video presentation is current gear head fashion. As the video moves forward, he does point out difference between bars and no bars.

FCM is considered THE place for suspension expertise on Miata's and others.

Happened across this as I'm currently dealing with problems with the front anti-roll bar brackets on a Miata.. Design and production FAIL...



Bernice


Bernice, I started to watch the video but the guy sort of mumble at the start and I got tired of looking at his mug. I have a feeling you could do a better job of explaining.
 
Yeesh. Seems like a nice guy with some interesting info to share, but rambled a lot.

I think he was saying that a stabilizer bar can sometimes reduce the contact patch and grip (on the inner wheel?) because the bar causes the wheels to work more in unison. So the inner wheel is more likely to lift and over bumps the left-and-right wheels cannot function independently as well.

Which totally makes sense and somtething I've always considered as well. With the size of our addco front stabilizer bars and the bushings which take up some of the slack (and I expect would dampen the overall effect) I like the experience for spirited street driving. The X rolls a little less and "feels" a little more planted (even if it's not -- I have no empirical data).

Bernice, I started to watch the video but the guy sort of mumble at the start and I got tired of looking at his mug. I have a feeling you could do a better job of explaining.
 
Yes, getting past that rambling, current moto fashion personality is part of the challenge of watching this video.

At the core, it's message is anti-roll bars essentially tie the wheels together to varying degrees taking away their independence which negates the design concept of independent wheel suspension.

Over the years much has been discussed over the exxe not having anti-roll bars and adding them to reduce roll angles. As with most things, there are trade offs involved as to adding the bars or not.

Over the years of tinkering with the exxe chassis, I'm pretty much in the no anti roll bars camp and prefer significantly increasing spring rates with proper dampers to control them over adding the bars. This is NOT the solution for all roads or driving conditions as spring rates that are too high does not work well at all on bump roads. In this case, the bars with lower spring rate and again, proper dampers works better.

Then there is an entire world of how one wants the chassis to behave near or at the limit..

None of this is simple, yet the chassis in the exxe can be adjusted and set up to accommodate most chassis needs and driver expectations. This is the true value of the exxe chassis and what makes is so very special.



Bernice




Yeesh. Seems like a nice guy with some interesting info to share, but rambled a lot.

I think he was saying that a stabilizer bar can sometimes reduce the contact patch and grip (on the inner wheel?) because the bar causes the wheels to work more in unison. So the inner wheel is more likely to lift and over bumps the left-and-right wheels cannot function independently as well.

Which totally makes sense and somtething I've always considered as well. With the size of our addco front stabilizer bars and the bushings which take up some of the slack (and I expect would dampen the overall effect) I like the experience for spirited street driving. The X rolls a little less and "feels" a little more planted (even if it's not -- I have no empirical data).
 
Transferring bounce from one side to the other is the first thing the vid refers to and I agreed so that was another reason to switch off because I already knew it all.lol. For some reason I thought I should have sway bars on my 1975 X19 when I first got it. Probably because the 128's I had were equipped with them. Anyway I stuck a set on my 75 and the difference was noticeable in hard cornering but on the bumpy streets around here I decided it was not the best setup so I took then off. When I got my 84 X19 I thought about installing the bars but the everyday ride is a lot better with out, but I will hang on to the bars just incase something comes up that I want them.
 
I believe the Addco bar is 7/8". With soft (180lb/in) front springs, you definitely notice the less sharp turn-in when running the bar. In my case, the reduced roll outweighed the numb response and grip reduction. In a 45' slalom, maintaining chassis composure and being able to change direction quickly made a huge difference. The guy made a good point about using as little bar as necessary. The firmer your springs, the less bar you need. Running a huge front bar with soft springs is a recipe for understeer and poor turn-in.

I had a huge front bar on my 350Z for a long time and battled with poor initial turn-in. I removed the bar and put the stock one back on prior to selling the car. Going back to the stock bar made a huge improvement.
 
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