Designed by lawyers, is the term UUC’s Ben Liaw used to describe stock suspensions when we called to get information about the Sway Barbarians. Lawyers design cars to understeer at the limit. In anything, except for a limited-production, high-dollar sports car, lawyers have more to say in the suspension design than the designers themselves. What this means to you is less performance from your stock Bimmer—or more untapped potential, if you’re a “glass half-full” type like the UUC Motorwerks staff.
In most cases, if you go into a turn too fast, your BMW will plow, and the easiest way to get the car balanced again is by letting off the gas. It’s the ideal setup, as the general public’s first reaction to a car that feels as if it is out of control is to hit the brakes. A suspension that is set up to balance out if you let up on the gas makes a lot more sense than one that requires the driver to make a conscious decision to alleviate the potentially dangerous situation., If, however, your intent is to extract the most performance from your BMW and its renowned handling capabilities, then you will want to do away with lawyers... errr, rather the suspension settings that lawyers “design” into new cars.
With the advent of the independent suspension, sway bars became an immediate necessity if a car was to be driven and turned. While independent suspensions allow more of the tires’ treads to be placed on the ground in a turn, they can also create a lot more body roll. An independent suspension causes the tire to move in an arc as it is forced up or down. If each side of the suspension worked independently, and a turn was taken hard enough, the tires that bear the brunt of the car’s weight during that turn (The tires on the outboard side.—MAX) would be forced up into the fenderwell. The inboard side tires could then be lifted off the ground as the suspension went to full extension. Also, the body of the car would tilt or roll in the opposite direction of the turn. This, of course, limits a car’s performance abilities, as the car cannot maintain decent lateral traction if only two tires are in adequate contact with the ground and the car’s center of gravity is positioned somewhere over those tires. Sway bars force the car and its suspension to work together.
Sway bars link the chassis to the bottom of the suspension components and also link the suspension components to each other. By virtue of an independent suspension’s setup, your Bimmer’s chassis is linked to the top of the suspension at each of four points by the strut mounts and to a lower pivot arm that those struts attach to. The pivot arms could rotate freely with only their springs and dampers acting on them, if sway bars were not in place. Sway bars, however, provide another force that act on those pivot arms. The sway bars mount to the chassis at two points on both the front and rear of the car and also to either the shocks/struts, or to the pivot arms themselves. By mounting to chassis pick-up points and to suspension components, sway bars help to improve your Bimmer’s handling abilities, as well as do away with excessive body roll that would make a car extremely difficult to drive comfortably. And that’s where UUC picks things up.
What some sway bars offer is “show performance.” They appear to offer performance simply because they reduce body roll at the front of the vehicle, where it is most noticeable. In designing its sway bars for the E-46, UUC delved deep into the science behind sway bars in order to come up with a superior design that would offer real performance. Beginning with simple physics, UUC determined that if bushing material remains the same, mounting location remains the same, metallurgy remains the same, and there is no difference in end link characteristics (And therefore there is no difference in the way the sway bars interact with the car’s suspension.—MAX), then a simple increase in thickness of the sway bar will increase the rigidity by an easily determinable factor. Then, through experimentation, a numerical value for that ideal factor by which to increase the rigidity was determined. Next, UUC decided to change those characteristics that helped to determine the ideal factor in order to further improve upon the bars’ performance abilities. To begin with, UUC wanted to make a sway bar that wouldn’t suffer fatigue or break. Mild steel is used in the stock BMW sway bars, as well as many other aftermarket bars, so the company wanted to use some sort of steel alloy, as all steel has a similar resistance to deflection. This similarity in deflection resistances between different types of steel means that if sway bars are of the same diameter but constructed of different materials, their effective spring rates will be close enough that the handling characteristics they promote will be the same. Never ones to leave well enough alone, UUC found that an alloy of steel with chrome and molybdenumn it is more resistant to fatiguend will maintain its shape even after repeated flexing. The 4130 chrome-moly spring-grade steel that UUC uses costs about twice that of most of the mild steels used in other sway bars, requiring also a more involved manufacturing process because of the alloy’s resistance to change in shape. As an added bonus, the bars are given a thick zinc powdercoat to ensure longevity.
Though UUC doesn’t change the mounting locations of either the end links nor of the chassis pick-up points, it does make a few very important changes. By replacing the rubber bushings on both the front and rear bars with polyurethane ones, and replacing the rear end links with adjustable ones without bushings, UUC increases the bars’ effectiveness dramatically. Another extremely important design characteristic of UUC’s bars is their adjustability. By making the bars adjustable, they allow for the user to dial in his preferred settings, even if it is different from what UUC has set up as ideal from all of its calculations. What all this means to the driver is more neutral handling at the limit—the car will neither understeer nor oversteer—as well as a dramatic reduction in body roll and better lateral traction through turns. The thicker bars make the chassis remain flatter throughout the turn because their increased spring rate exerts a greater force on the chassis, which transfers this force to the opposite (Inboard.—MAX) wheel.
Installation and setup is a breeze. Simply remove your old sway bars and install the new ones. The new urethane bushings must be lubricated with the included grease, and the stock chassis mounting brackets must be re-used, but a total of sixteen bolts are all that is required to get your Bimmer well on its way to better handling. UUC recommends that the front sway bar is set at full stiff, using the holes farthest from the ends, and that the rear bar be set at full soft, using the holes closest to the ends in order to give the car the most understeer available with the Sway Barbarians (Which is much less than stock.—MAX). From there you can tune the sway bar setup to your preferences. Sway bars are necessities on today’s independent suspensions. UUC Motorwerks’ Sway Barbarians are a necessity for the BMW E-46 owner that is looking for the ultimate in handling from his Autobahn-bred machine. With less body roll, and better grip, you can be sure that you’ve gotten what you paid for and managed to pull one over on the lawyers of the world at the same time.