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How Stock Car Suspensions Work

        Auto | NASCAR Racing

Stock Car Sway Bars

When a car goes around a corner, its weight shifts from side to side. Anyone who's ridden in a car has felt that effect, when your body is pulled in the opposite direction of the turn. It's such a common experience that most people wouldn't notice it in an average car ride -- not unless their driver is going a little too fast.

­As stock cars race around oval tracks at high speeds, they deal with an extreme version of this effect. This body roll affects tire grip and performance. How well a tire grips the track depends on the weight pushing the tire into the track. When weight shifts off a tire during a turn, it has less grip and therefore less speed. And anytime parts of the tire leave the track, the driver has less control over the vehicle.

A sway bar helps prevent weight transfer. It connects the suspension of the car, the chassis and the body. Because each racetrack requires a different sway bar with varying stiffness, prepared teams often keep many sway bars in stock [source: Burt].

The stiffer the sway bar, the tighter the connection between the suspension and chassis, which minimizes body roll during a turn. But it's important to remember that sway bars that are too loose or too stiff could also present problems.

Sway bars twist when one of the tires goes over a bump. If both tires go over the bump evenly, the sway bar does nothing, but if one tire goes over a bump the sway bar counteracts the movement to keep the weight of the car from shifting [source: Diandra].

­ The chassis plays an important role in stock car suspension, too. Read on to learn more.