How do shocks and springs work

Of course, in the rear of the car, the steering rack — the assembly that includes the pinion gear wheel and enables the wheels to turn from side to side — is absent. This means that rear independent suspensions can be simplified versions of front ones, although the basic principles remain the same.

Because the carriage body was suspended from the chassis, the system came to be known as a "suspension" — a term still used today to describe the entire class of solutions. The slung-body suspension was not a true springing system, but it did enable the body and the wheels of the carriage to move independently. Semi-elliptical spring designs, also known as cart springs, quickly replaced the leather-strap suspension.

Popular on wagons, buggies and carriages, the semi-elliptical springs were often used on both the front and rear axles. They did, however, tend to allow forward and backward sway and had a high center of gravity. By the time powered vehicles hit the road, other, more efficient springing systems were being developed to smooth out the ride for passengers.

But what about the suspensions of specialty cars, such as hot rods, racers or extreme off-road vehicles? Although the suspensions of specialty autos obey the same basic principles, they do provide additional benefits unique to the driving conditions they must navigate.

What follows is a brief overview of how suspensions are designed for three types of specialty cars — Baja Bugs, Formula One racers and American-style hot rods. The Volkswagen Beetle, or Bug, was destined to become a favorite among off-road enthusiasts. With a low center of gravity and engine placement over the rear axle, the two-wheel-drive Bug handles off-road conditions as well as some four-wheel-drive vehicles.

Of course, the VW Bug isn't ready for off-road conditions with its factory equipment. Most Bugs require some modifications, or conversions, to get them ready for racing in harsh conditions like the deserts of Baja California. One of the most important modifications takes place in the suspension. The torsion-bar suspension, standard equipment on the front and back of most Bugs between and , can be raised to make room for heavy-duty, off-road wheels and tires.

Longer shock absorbers replace the standard shocks to lift the body higher and to provide for maximum wheel travel. In some cases, Baja Bug converters remove the torsion bars entirely and replace them with multiple coil-over systems , an aftermarket item that combines both the spring and shock absorber in one adjustable unit.

The result of these modifications is a vehicle that allows the wheels to travel vertically 20 inches 50 centimeters or more at each end. Such a car can easily navigate rough terrain and often appears to "skip" over desert washboard like a stone over water.

Lightweight, composite bodies, powerful V10 engines and advanced aerodynamics have led to faster, safer and more reliable cars. To elevate driver skill as the key differentiating factor in a race, stringent rules and requirements govern Formula One racecar design.

For example, the rules regulating suspension design say that all Formula One racers must be conventionally sprung, but they don't allow computer-controlled, active suspensions. To accommodate this, the cars feature multi-link suspensions , which use a multi-rod mechanism equivalent to a double-wishbone system. Recall that a double-wishbone design uses two wishbone-shaped control arms to guide each wheel's up-and-down motion.

Each arm has three mounting positions — two at the frame and one at the wheel hub — and each joint is hinged to guide the wheel's motion. In all cars, the primary benefit of a double-wishbone suspension is control. The geometry of the arms and the elasticity of the joints give engineers ultimate control over the angle of the wheel and other vehicle dynamics, such as lift, squat and dive.

Unlike road cars, however, the shock absorbers and coil springs of a Formula One racecar don't mount directly to the control arms. Instead, they are oriented along the length of the car and are controlled remotely through a series of push and pull rods.

They translate the up-and-down motions of the wheel to the back-and-forth movement of the spring-and-damper apparatus. Like Baja Bugs, classic hot rods required significant modification by their owners.

For hot rod enthusiasts, this was exactly what they wanted, for it allowed them to install more reliable and powerful engines, such as the flathead Ford V8 or the Chevrolet V8. One popular hot rod was known as the T-bucket because it was based on the Ford Model T.

The stock Ford suspension on the front of the Model T consisted of a solid I-beam front axle a dependent suspension , a U-shaped buggy spring leaf spring and a wishbone-shaped radius rod with a ball at the rear end that pivoted in a cup attached to the transmission.

Ford's engineers built the Model T to ride high with a large amount of suspension movement, an ideal design for the rough, primitive roads of the s.

But after World War II, hot rodders began experimenting with larger Cadillac or Lincoln engines, which meant that the wishbone-shaped radius rod was no longer applicable.

Instead, they removed the center ball and bolted the ends of the wishbone to the framerails. This " split wishbone " design lowered the front axle about 1 inch 2. Lowering the axle more than an inch required a brand-new design, which was supplied by a company known as Bell Auto.

Throughout the s and s, Bell Auto offered dropped tube axles that lowered the car a full 5 inches 13 centimeters. Tube axles were built from smooth steel tubing and balanced strength with superb aerodynamics. The steel surface also accepted chrome plating better than the forged I-beam axles, so hot rodders often preferred them for their aesthetic qualities, as well.

Some hot rod enthusiasts, however, argued that the tube axle's rigidity and inability to flex compromised how it handled the stresses of driving. To accommodate this, hot rodders introduced the four-bar suspension , using two mounting points on the axle and two on the frame. At each mounting point, aircraft-style rod ends provided plenty of movement at all angles. The result? The four-bar system improved how the suspension worked in all sorts of driving conditions. Sign up for our Newsletter!

Mobile Newsletter banner close. Potential energy is stored energy and kinetic energy is energy in motion. This thermal energy is then degenerated in hydraulic fluid. Shock absorbers are an oil-filled cylinder. The up-and-down movement of the piston forces small amounts of fluid through orifices tiny holes in the piston head.

Shock absorbers are also velocity-sensitive. Cotter pins, self-locking nuts and interference-fit bolts should be replaced with new ones. To achieve accurate suspension height, always torque the suspension bushing pivot nuts with the full weight of the vehicle on the suspension system and at normal suspension height. Advertisement Generally speaking, the vehicle suspension height will change a small amount after driving a few thousand miles. To prevent unwanted tire wear or safety issues to arise from a new spring replacement, retorquing suspension bolts and rechecking alignment angles is a recommended operating procedure.

Service: Servicing Custom Wheels. Magazine Current Issue Past Issues. Connect with us. Advertise Subscribe Contact Us. By Gary Goms. Historically speaking, the steel multi-leaf spring is one of the oldest and most widely used spring designs in suspension systems.

In addition, a leaf spring tends to act as its own rebound dampener due to the friction of the leaves rubbing together.

As a vehicle gains speed, the springs begin to absorb the impact of striking irregularities in the road surface. As rebound control deteriorates due to normal shock absorber wear, the vehicle will begin to experience poor ride, steering response and handling control. Reassembly of MacPherson struts can be aided by scribing a crayon line along the length of the strut to indicate the relationship of the parts. When replacing coil springs, ensure that the springs are indexed correctly from left to right and seated correctly in the spring seats located in the control arm and chassis.

Generally speaking, the vehicle suspension height will change a small amount after driving a few thousand miles. Unlike struts however, they are not designed to be subject to high side loads. Built using similar components to conventional shock absorbers, spring seat shocks are also sealed requiring full replacement.

Shock absorbers are pump-like devices which keep your vehicle's tyres in contact with the road surface by controlling the rebound of its suspension springs.

As long as your vehicle's tyres remain in contact with the road, steering, road handling and braking response will be optimal, helping to keep you safe. Shock absorbers explained. Testing, testing and testing.

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