La stabilizer bar is in charge of reduce sway of a vehicle when cornering. It is a more or less flexible metal bar that joins the two wheels of the same axle and is also attached to the chassis. Its design causes that when one of the two sides of the body sinks, so does the other to increase the stability of the car.
The connection of the stabilizer bar to the suspension assembly is made by means of connecting rods. These have two ball joints that allow certain movements while maintaining the bar fixed where it should. Although the area to which the stabilizer bar is attached can be modified depending on the type of suspension.
stabilizer bar function
The function of the stabilizer bar is to limit the inclination of the car body when cornering. this bar opposes the natural tilt caused by inertia, through its own torsional stiffness. Its ends end in the form of rods that are anchored to some part of the suspension.
The bar itself is fixed through the center to the chassis of the car, but allowed to rotate, so that torque can be transmitted from one side to the other. In this way, when one side of the suspension goes down turning that "arm", so will the other, sinking in turn the suspension on the other side.
More thickness, less sway
There are many types of stabilizer bars, as this depends on the vehicle's suspension scheme. However, we can say that they all have in common that they are always placed in the same position. Namely, perpendicular to the longitudinal axis of the car.
The thicker the bar, the more resistance to torsion it will have. and the less the car will lean. An effect that can also be achieved with a harder metal and therefore more resistant to torsion, but which must have sufficient elasticity so as not to break.
Stabilizer bar less thick: more comfort
However, not for that reason it is necessary to place a bar as thick as possible always. A balance must be found between the comfort provided by the less thick bars and the stability of those with a larger diameter.
In addition, a problem that bars thicker than recommended for a model can cause is that it can interfere with the proper functioning of both sides of the suspension.
Stabilizer bar failure
bar breakage
Normally, the stabilizer bars have no breakdowns in the entire useful life of a vehicle. In fact, the only possible damage to a bar would be its own breakage. But that is not very likely since its flexibility is prepared to assume the deformation caused throughout the suspension travel.
That is, even if one wheel goes in as far as it will go and the other comes out as far as possible, the bar will withstand the torsion. Of course, this is the case under normal conditions of use and as long as the vehicle in question has the bars with which it was designed.
Slack in the links
However, items that can be damaged more easily are connecting rods of the stabilizer bar. With the passage of time these pieces can take on slack and, at a certain point, it will be necessary to change them for new ones. Although its price is usually very low, except in premium or luxury cars.
stabilizer bar mounts
Although rarer, they can also reach damage to the stabilizer bar mounts to the body of our car. But this does not usually happen on its own.
Unless it is a factory defect, they are usually damaged because the car has suffered an accident that has thrown its suspension system or even the chassis out of balance. So even though these mounts are very cheap to change, you may need to check for any other issues.
Stabilizer Bar Bushes
The silent blocks are the rubber pieces placed in various parts of the stabilizer bar. Thanks to them, metal-to-metal friction is avoided when the bar rotates. It also reduces the transmission of noise and vibrations to the chassis (hence the name silentblocks). In addition, they allow the assembly of pieces to have the necessary flexibility where it is needed.
When the stabilizer bar bushings deteriorate or break, certain gaps are created. For this reason, the symptoms of deteriorated silentblocks are abnormal body movements when turning and knocking and scraping noises. The most common are the silentblocks simply called Media. Although there is also talk of silentblocks when mentioning, for example, the rubbers of the tie rods stabilizer.
stabilizer bar prices
Stabilizer bars come in a wide range of prices. As well as the variety of prices that the cars themselves have. Anyway the Complete kit It has a price that varies between 200 and 400 euros for cars in the general segment.
In any case, you will see that the sale of the complete stabilizer bars is not so common. Normally only one component is damaged, that is why parts such as the suspension arm bushes (between 5 and 20 euros), the Media (between 4 and 10 euros), the tie rods of the stabilizer bar (between 30 and 50 euros), etc.
Not to be confused with torsion bars
Since stabilizer bars and torsion bars are based on the same principle, are often confused. The name torsion bar is often used to refer to two other elements of the car. The first are the torsion bars used in some suspensions, which join each wheel to the chassis and whose mission is to suspend the vehicle to isolate it from irregularities in the pavement.
The second are the torsion bars connecting the damping shafts to increase the chassis torsional stiffness. Despite its name, its function is not to twist or to twist as little as possible. They are only carried by some cars with a sporty focus, either from the factory or by subsequent modifications. A good example is the one that can be seen in the trunk of the Hyundai i30 N.
Images 3 and 5 – Witold Waschut, Matthew Blaine