Guide to Buying an Anti-Roll Bar

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Guide to Buying an Anti-Roll Bar

There are many reasons why vehicle owners choose to buy an anti-roll bar, also known as a sway bar, anti-sway bar, torsion bar, and stabiliser bar. An important part of a vehicle's suspension, this part is often included in an anti-roll kit and provides a vehicle's suspension with stability. Choosing an anti-roll bar that fits a particular vehicle is not enough. Buyers must also consider the use of the anti-roll bar, which means understanding its function and features.


The main components of anti-roll bars

Physically speaking, an anti-roll bar is pretty basic. It is, literally, a stiff bar or tube that connects the two sides of a vehicle's suspension. Usually between 2 cm and 5 cm in diameter, the anti-roll bar affixes to the frames of the two front or two rear wheels of a vehicle through brushings, which rotate along with the speed of each wheel. Arms from the rod of the suspension then attach to either side of the bar.

Often included as part of an anti-roll kit, this bar provides stability at a rate consistent with the remaining parts of the kit. Most vehicles, regardless of size or type, include a front anti-roll bar. However, sportier models generally include one at both the front and rear ends of the suspension.

Adjustable anti-roll bars

An important subtype, people commonly use adjustable anti-roll bars on sports cars and other performance vehicles, specifically those used in auto racing. As their name suggests, adjustable anti-roll bars are easy to tweak when a car is in the pit by altering the length of the bar, and hence, the resistance or stiffness it adds to the suspension.


How anti-roll bars work

In its most concise definition, the purpose of an anti-roll bar is the reduction of body roll through the addition of roll resistance to the springs within a vehicle's suspension. However, the way in which an anti-roll bar accomplishes this depends on roll resistance and coupling.

Understanding roll resistance

The main function of anti-roll bars is to help the body of the vehicle resist rolling when taking turns, especially at high speeds. This function, called roll resistance, takes place because the positioning and strength of the anti-roll bars adds pressure to the suspension springs, helping the vehicle to maintain its contact with the road surface, improving overall traction and handling as a result.

In the event that a car does roll, this means that one set of wheels loses its contact, however minor, with the surface of the road. As a result, the suspension itself changes its geometric relationship with the road. Since the suspension should maintain a parallel relationship with the road surface, body roll affects its protective abilities and, ultimately, may cause the entire vehicle to roll under the right circumstances of conditions and speed.

Another benefit of an anti-roll bar when it comes to roll resistance is that it adds pressure to the springs without the need to add stiffness. As a result, the overall ride is smoother, since the springs are able to absorb shock and maintain stability in other instances.

Understanding roll coupling

The other function of an anti-roll bar is tuning the roll coupling of the vehicle's chassis. Roll coupling is the relationship of roll resistance to both the front and rear ends of a vehicle. Balancing this ratio between the two effects overall vehicle traction and directly impacts whether the vehicle itself understeers or oversteers.

When it comes to its impact on roll coupling, an adjustable anti-roll bar helps to compensate for understeering or oversteering by balancing the front and rear end roll resistance of the suspension in a precise manner.


Features to look for

There are specific features of a sway bar that impact its overall function, which vehicle owners should note, whether buying the bar as part of a kit or as an individual part. Namely, to increase its effect, drivers want to upgrade to a sway bar that is stiffer and thicker than its original stock or OEM part. Also, drivers interested in racing or the performance aspects of their vehicle are better off purchasing an adjustable anti-roll bar.


How to buy an anti-roll bar on eBay

Using the search bar on eBay to buy auto parts for suspension repair or upgrades is an easy way to save time and money. There are many different types of anti-roll bars and anti-roll kits available from the reliable sellers and finding them is easy. Simply begin a search using the main search bar on any page of the site. Once you receive results, limiting your selection is easy with the limiters provided that include features, such as price, brand, and condition of products.

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