What is an anti-roll bar?

Hidden away from our eyes beneath every car is a complex array of rods, levers, and springs that make up a suspension, but some suspension setups have a very interesting concept called an anti-roll bar. How it helps is in reducing body roll of a vehicle during fast cornering or over road irregularities. It does this by forcing each side of the vehicle to a similar height, thereby allowing for a firmer, more pliant ride.

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In a fast turn, a vehicle tends to drop closer onto the outer wheels, and the anti-roll bar, working away within the confines of the suspension setup, soon forces the opposite wheel to also get closer to the vehicle. As a result, the vehicle tends to hug the road closer during a direction change, where all wheels are closer to the body. After the fast turn, then the downward pressure is reduced, and the paired wheels can return to their normal height against the vehicle, which is kept at similar levels by the connecting bar.

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However, it is not a perfect solution to the problem of a car leaning over during turns. Because an anti-roll bar connects wheels on opposite sides of the vehicle, the bar transmits the force of a bump on one wheel to the opposite wheel. This can have an adverse reaction on rough or broken pavement, anti-roll bars can produce jarring, side-to-side body motions, which increase in severity with the diameter and stiffness of the sway bars.

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