a question about anti-sway bars.
 

I understand that the point of an anit-sway bar is to keep your car from learning when you go around corners, but what has never been explained to me is what is the difference in thickness of anti-sway bars?

Also, is there a disadvantage to using an anti-sway bar?

Thanks.

the thicker the anti-sway bar, the harder it is for the car to sway. The only advantages i know of for not running a bar is in dragracing

-Jacob

Someone else may explain it better but i'll give it a shot.

Sway bars allow the car to have more mechanical grip at the front or rear to help cure under or oversteer. High end sports cars and race cars have adjustable sway bars that allow you to fine tune the car. Basically it works like this, if your car is oversteering a lot (not power oversteer) then you'd want to loosen up the swaybar stiffness in the rear. If the car is understeering or pushing in corners, you'd loosen up the bar up front. You can work them both ways, but that's the jist of it.

From the Suspension and Handling Links sticky in the Suspension section:


Everything about Sway Bars by Grassroots Motorsports

You guys should check that sticky more often ;)

In a nutshell sway bars are used to adjust weight transfer between the left and right sides of each axle. A sway bar is a spring that acts in torsion. The thicker the bar the stiffer the spring.

So basically if my car is having a problem with oversteering, I should add a front sway bar?

It may be possible that going to a larger front bar would help. My first thought would be to vote for a smaller rear bar or no rear bar. Though you don't really give enough detail.

What car? What are you doing with it? When does the car oversteer? (entry, mid, exit?)

There are disadvantages to a large bar. Depending on what the car is used for and all of the other variables a bar may not be the answer.

I don't think anyone can give you a good, true and reliable answer without more detail.

Right, id ask firstly how you're driving the car before approaching the mechanics of it.

Just Solo2 Autocross. I'm still pretty new to the whole thing actually. I've noticed the car seems to oversteer just a bit, but once again, I'm pretty new to whole thing.

you should also let us know, what you currently have done to the suspension, what your alignment settings are and what tire/wheel sizes.

For an autocross car I would rather have stiffer springs and smaller (or no) sway bars. But if you drive the car on the street then you have to make certain concessions.

Umm, you still haven't given us any details about the car and current setup.

FB, FC, FD, Other?

Tires?

Other suspension stuff? Shocks, springs?

If you are experiencing just a mild oversteer you could adjust simple things like tire pressure to get rid of it. Or maybe the shocks if you have adjustables.

Is the oversteer seem to be on corner exit when you are putting the power back on? Is the oversteer at the corner entry? Are you releasing the brakes after you have turned in? Is the oversteer starting half way through a turn before you are back on the gas and after the initial turn in?

Without that type of info, a recomendation is just a shot in the dark.

"Also, is there a disadvantage to using an anti-sway bar?"

If you go too stiff with bars, you loose the independent suspension design (FD). Example: Soft springs and stiff bars is a bad combo for rough tracks.

advantages/disadvantages

I'll skip for the moment finding the right balance between front and rear traction.

The main advantage of stiffer sway bar is that the car leans less so the tires stay flatter on the ground. The second advantage is that a stiffer sway bar speeds up transitions. It reduces the time it takes to go from full lean on the right to full lean on the left.

The disadvantage is that it puts more load per inch of suspension travel on the tires. So the tire is more easily overloaded in bumpy ground. The car becomes less forgiving of minor road irregularities and driving style. It also becomes noisier.

By the way, springs and sway bars interact. It's better to have stiff springs and use a soft sway bar only to balance front and rear traction but that will be very harsh on the street. The usual compromise is softer springs and stiffer sway bars.

ed

Actually there are two schools of thought on the soft bar hard springs arguement, Colin Chapman of Lotus fame always tended towards softer springs and bigger anti sway bars, but others including BMW tend to go the opposite, it all depends on your style and what works best for you.

Start playing with your tire pressures, ie: a good baseline would be 36 front and 34 rear then experiment up and down, keep notes for future reference. Also try disconnecting your rear bar for a couple of runs and see how it works, dont go spending money until you've tried and learned from the basics. Make one change at a time or else you wont know what worked and what didn't.

With my FB I have removed the rear bar and now I am playing with bushings to tighten the front stock bar