View Full Version : Sway Bars - Hot Set-up?

01-09-2008, 09:45 PM
Any suggestions for a hot setup on sway bars (a/k/a roll bars) for a 1998 M-3 will be appreciated. I have seen a variety of sizes and manufacturers (below). Any guidance about which setup and/or manufacturer would work best for driver school/track conditions will be appreciated. Thanks.

Model Front Sway Bar Rear Sway Bar Front Stiffness Rear Stiffness
Stock '96-99 M3 0.905 (23mm) 0.787 (20mm) 0 0
UUC 1.0" (25.4mm) 0.9375" (23.8mm) 49% 101%
Racing Dynam 1.0625" (26.98mm) 0.875" (22.225mm) 90% 52%
Dinan 0.875" (22.225mm) 0.875" (22.225mm) -13% 52%

01-09-2008, 10:15 PM
depends on lots of stuff like spring rates, tire size, driver experience and driving style. there is no "hot set up" that works for all. they all work, but solve different problems.

bar diameter is not the only variable that effects the rate of the bar. end link position is a major factor.

they all work, but solve different problems. what problem are you trying to solve?

01-09-2008, 11:25 PM
Thanks for getting back to me. Assuming any sway bar I get has the same adjustability and I have the same set-up otherwise (tires, driving style, etc), which sway bar diameter will produce the best track times (on the same track)? Thanks for your guidance.

01-10-2008, 12:40 AM
again, there is no "fastest" answer...it depends. some folks run soft springs and stiff sways, some run stiff springs and no sways. sway bars are used to correct particular handling issues, not go faster. the balance between front and rear sway bars is different for different applications. for example, on my race car i have run no rear bar at all, the smallest stock bar available, and a ground control adjustable bar. which one was fastest? none of them. they were all used in conjunction with various spring rates and damper settings to change the way the car handled.

how much track time do you have? and back to my original question...what is your car doing on the track that you want to correct? sway bars are just one method to change handling.

01-10-2008, 06:10 PM
I believe sway bars should be used as a an very adjustment to handling of any car. The bars should be adjustable. Bigger is not always better when it comes to sway bars. And make sure the busihing for the sway bars are readily available and I would suggest buying spares when you purchase the bars.

Just replacing the the sway bars in your car with something larger may lead to ripping out the sway bar mounts or other problems,

Your car is 10 years old the shocks and struts need to replaced as do most if not all the bushings in the suspension if you are going to use the car on the track. The springs are also 10 years and fatigued and for a car that sees track time probably should be replaced. A well thought out suspension package is better than a haphazard thrown together mess. However, suspension packages from Dinan and Racing Dynamics et al are usually overpriced and rpomise more than they deliver. Springs that lower your car may not be stiffer and you need to know the spring rates etc.

And remember you get a better return on your investment by making the driver better not the car. Chances that changing the sway bars in your car will make it faster are about as good as changing all the air in all the tires in your car including the spare.

Dave Apker and the collies

Nick325xiT 5spd
01-12-2008, 11:31 PM
There are lots of things to do in conjunction with bars, but I recommend the H&R bars with the Turner adjustable front endlinks (ball joints, rather than spherical bearings).

01-14-2008, 07:42 PM
First, I'll underscore what MLYTLE is saying about 10 times. It just depends on what you are trying to do. Sway bars just effect the relationship between the left and right tires of the car. Balance *between* the bars, springs, and shocks is a whole 'nother story.
I installed UUC bars on my 98M3 trying to reduce body roll, which I thought was causing the inside front tire to go airborne on corner exit. Wrongo. Tire was in the air the exact same about of time, just 2 inches lower. Removing the spare tire helped more that that. Raising the rear spring rate cured the problem, and with a balanced increase on the front spring rate, and improved dampeners, vastly improved the handling. TCKline kit. Still like the bars, though.
If you do go with heavier bars, please get a rear swaybar reinforcement kit installed asap. Heavy bars will tear out the rear mounts right away.

Better to just leave it stock and go to about 20 drivers schools, then you will know what to do.

Good luck regardless.

01-16-2008, 11:18 AM
Everyone's advice is right on, but to give you a definitive answer....most find that a larger front adjustable bar (25-28mm) works best, along with a stock or smaller rear adjustable bar (19-22mm).

Like everyone else said, spring rates, damping, and especially alignment will all have a significant effect.