A car's suspension is designed to improve its road holding ability, handling, and ride comfort while it is being driven at speed. Most standard suspensions on modern cars feature coil springs and shock absorbers as basic components. Coil springs absorb the energy created when driving over the road surface and are controlled by shock absorbers, also known as oil-filled dampers. The standard suspension fitted to a car is designed to suit most drivers in most circumstances. Cars sold as sports models often have sports suspensions, while luxury cars tend to have suspensions that promote the comfort of the car's occupants.
Performance suspension systems can be tailored to a driver's needs. In addition, performance suspension parts are often of superior quality when compared to standard parts. For road use, the suspension's height is lowered and spring and shock absorber rates increased for better handling without a detrimental effect on the comfort of the ride. High-end performance suspension allows the driver to adjust the height, bump, and rebound settings.
Before shopping for performance suspension parts, learn which parts are required to build an improved suspension system and what to look for in each part. Performance suspension parts are available from garages, car part suppliers, and online from sites like eBay..
Components of Performance Suspensions
The majority of performance car suspensions include coil springs, shock absorbers, and anti-roll bars. In general, spring and anti-roll bar rates are increased or stiffened for a more sporty feel. Ride heights are reduced by installing shorter coil springs with modified shock absorber settings. Be careful of choosing suspension components that leave the suspension too low and too soft. Understanding the parts and techniques used in building performance suspensions allows drivers to choose parts that are best suited to their needs.
Springs for Performance Suspensions
Springs are used to lower or raise the height of the car. The lower the springs, the lower the car's centre of gravity, making it more stable for improved handling. Springs usually need to be installed using a spring compressor.
Lowering Springs for Performance Suspensions
Lowering springs are the most popular type of coil springs found on performance car suspensions. These components are designed to improve the car's handling and road holding capabilities and are adjusted by increasing the spring rates or making the springs stiffer. Cars are usually lowered from 25 to 80 millimetres.
Effects of Lowering the Car
It is important to bear in mind that stiffening the springs affects the car's ride comfort and the driver and passengers are more likely to feel the effects of the road surface. Lowering the car also makes it difficult to navigate areas with high pavements, a lot of speed bumps, or uneven road surfaces. It is best to find a happy medium between handling and comfort to keep the car practical enough for everyday use.
Materials for Lowering Springs
Lowering springs are made of high quality steel blends that are either hot or cold formed. Cold formed springs are preferable as they tend to be stronger. Springs that have undergone shot peening, where beneficial surface stresses are introduced, have a longer lifespan. When choosing how much the car should be lowered, take the age of the vehicle into account. The springs on older cars tend to sag, making the intended lowering effect less than specified. The specifications are based on the car's original height when it was new. Where spring rates are not mentioned, choose longer lowering springs to reduce the chances of suspension damage when the car reaches it lowest point.
Shock Absorbers for Performance Suspensions
Shock absorbers are also known as dampers or shocks. These parts have two functions. Their high speed action controls the road spring once it is compressed by uneven sections of the road surface. Their low speed action offers resistance when the car leans while turning a corner. Performance shock absorbers usually use oil as a damping medium, with gas pockets to assist the main damping action during heavy use. Gas dampers are found on racing cars and are not intended for road use.
Lowering Springs for Shock Absorbers
It is important to match the shock absorbers to the lowering springs. Lowering springs with drops of more than 35 millimetres usually require shock absorbers with a shortened piston action. If the springs do not have at least as much travel as the shock absorbers, then the shock travel is reduced, the spring coils bind and become over stressed, severely compromising the shock absorbing performance. Keeping standard shock absorbers in place also means that they cannot handle the added pressure and wear out much faster.
Installing Shock Absorbers for Performance Suspensions
Choosing the right shock absorbers is one of the more difficult aspects of installing a performance suspension. The easiest option is to buy shock absorbers with adjustable damping to allow fine tuning once they are fitted. Consider adding bump stops, which are small polyurethane blocks that protect the shock absorbers if the car falls to its lowest point. Choose bump stops that are not so hard that they increase the effective spring rate when struck. The right bump stops also make the car's suspension more predictable when driving over rough roads.
Coilover Kits for Performance Suspensions
Coilover kits are a combination of springs and shock absorbers that are flexible and adjustable, which makes them the perfect option for those who want to upgrade their springs and shock absorbers. If the driver needs to lift the car off the road over rougher terrain, he or she can simply adjust this component. It can be lowered again for smoother driving conditions. Coilovers typically offer heights between 30 and 80 millimetres. High-end coilover kits also allow the motorist to adjust the stiffness or spring rate of the suspension.
Torsion Bars for Performance Suspensions
Some suspensions feature torsion bars instead of rear coil springs. These components consist of a length of sprung steel that runs across the width of the rear of the car. It is possible to lower these bars, but this is best left to a qualified mechanic.
Strut Bars for Performance Suspensions
Strut bars are also known as strut tower bars or strut braces, and are designed to tie two opposing strut towers together to form a single unit. The bar reduces the flex that the towers experience during hard cornering, keeping the wheels in position. This helps to keep the tyres in the desired position on the road, improving traction in turns. Strut bars reinforce the car's subframe, improve chassis stiffness, and makes steering more responsive.
Anti-Roll Bars for Performance Suspensions
Anti-roll bars are shaped lengths of sprung steel that are attached to the suspension or chassis at both ends, tying the lower suspension components together across the front and back. These bars keep the car flat when turning and improve cornering at high speeds.
Sports Suspension Kits for Performance Suspensions
Sport suspension kits consist of lowering springs and shock absorbers with shortened piston rods and come in the same format as standard suspension systems. These kits include everything that is required to upgrade the suspension system. This is an excellent choice for those who simply want an upgraded suspension without getting too involved in the minute details of the settings and components. These kits usually improve handling and road loading without a significant loss of comfort.
Buying Performance Suspension Parts on eBay
When searching for car parts on eBay, always have your car's make, model, and year on hand. To find the suspension parts that you need, enter a phrase, such as "BMW performance suspension kit&", into the search bar, which is located conveniently on every page, to see the items available from eBay sellers. Refine your search by choosing the most suitable item features. If you would like more control over your search results, use the advanced search feature..
Evaluating Items and Sellers on eBay
Before buying on eBay, take a moment to evaluate the item and the seller. Click on an individual listing to visit the item listing page.. Here you can find details such as the full item description, photos of the item, buying options, the seller's accepted payment methods, postage and packaging costs, and the seller's feedback information. Always read the full item description before committing to a purchase. If you are buying a large or bulky item, search for local sellers who allow collection to save time and postage costs.
The seller feedback feature allows you to see what other buyers have to say about specific sellers' products and customer service. Getting to know the seller before you buy means that you can shop with confidence.
Replacing a car's suspension with a performance system usually means improved handling and road holding ability, which is achieved by stiffening the suspension. It is important to bear in mind that this usually means a slight loss in comfort, but most drivers feel that this is negligible when compared to the benefits derived from upgrading.
Lowering springs are used to lower the suspension and, as a result, the car's centre of gravity. If the car is an older model, remember to take into account that it may not respond to modifications according to the manufacturer's specification. In addition, lowering the car too much causes problems when driving on uneven surfaces or in areas with many speed bumps. The car's shock absorbers should be replaced to match the springs. The addition of anti-roll and strut bars further improve handling.
Those who simply want to improve their car's performance without focusing on the finer details of suspension mechanics should consider sport suspension or coilover kits as these usually include everything necessary for installing a performance suspension. When modifying a car, always ensure that it is still able to pass its annual Ministry of Transport (MOT) test. eBay sellers offer a wide variety of performance suspension parts, including kits and individual components.