What is an anti roll bar?
The anti-roll bar is a C-shaped bar, commonly made up of a metal rod, which connects the two independent wheel suspensions of the same axle.
In other words, it is a torsion bar which, if the two suspensions to which it is connected are stressed in a different way (one in compression and one in extension), limits the fact that they can work with a very different excursion.
The effects of an anti-roll bar
The main function of the anti-roll bar is explained unambiguously by its name. Its task is in fact to improve the stability of the car and to reduce the roll during a curve. This happens because this element is able to transfer part of the force from the suspension not in compression to the one in operation, thus helping to increase stability.
A stiffer anti-roll bar will force the wheel-suspension unit to respect the characteristic angles set as much as possible; first of all the Camber. It means that the tires will maintain the set angle of inclination with respect to the vertical line perpendicular to the ground even during greater efforts.
Generally speaking, this approach has several consequences:
- the tires warm up rather quickly;
- tires reach higher operating temperatures;
- the vehicle is more precise but more grumpy;
- in the event of loss of stability, the vehicle is easier to pick up;
- in the event of a bumpy or wet surface, the vehicle will be undriveable.
The adjustment of the anti-roll bars
In the case of vehicles with stabilizer bars present both at the front and at the rear:
- a much stiffer anti-roll bar at the front than at the rear will easily induce understeer in the vehicle which will most likely refuse to enter the front when cornering;
- vice versa, if the front anti-roll bar is too soft compared to the rear one, it will be easy to trigger the oversteer.
Note: if we excessively soften the rear anti-roll bar or excessively harden the front one then will we get the same effect? Understeer!?! This is not entirely true: understeer undoubtedly triggers in both cases but with different effects on tire temperatures and vehicle handling. Therefore, performing either one or the other operation is not exactly the same and you need to know when to operate in one way and when in the other. Generally this is done by also checking the temperature of the tires and thus observing the way in which they work.
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