Shock absorbers are a necessity on all types of vehicles registered on our roads today, you’re your everyday cars, semitrailers, motor cycles, golf carts, railroad cars, motor scooters to caravans and even trailers. They are an integral part of all vehicles designed to control and reduce the sudden impact of the imposing and erratic change of direction of the wheels on the road surface. The function of a shock absorber is to keep the wheel/tyre in contact with the road surface at all times limiting the impact to the vehicle to the occupants and enhancing the drivability of the vehicle, combining the best possibility of safety with the performance aspects and control expected by the owner.
Whenever we perform a service on a vehicle we always will carry out a 28 point suspension check to ensure the overall condition of your vehicles suspension is maintained and always kept in a roadworthy condition. One of the key components that we test is of course your Shock Absorbers. By Performing a road test over smooth and rough terrain, we can listen for any worn components that could potentially be a hazard, once this is completed we will perform a rebound test to ensure the seals have not worn and are allowing the springs to rebound the vehicle after potentially hitting a bump in the road. Finally we also perform a visual inspection to check for any damage or leaking fluid from the internals of the Shock Absorbers.
The History and Evolution of the Shock Absorbers
Early in the 20th century when cars were trying to negotiate the then rough terrain that existed including rocks and pot holes, the original tubular shock absorber was constructed which was basically a crude oil filled devise having a piston with very small holes in the plunger restricting the ability of the oil passing from one side to the other, this “dampened” or restricted the springs ability to rebound keeping the wheels motion more stable and “glued to the road”. As time went on the invention of ‘Double action type shocks became widely accepted with companies like Monroe pioneering the development in these areas. Most American car manufactures were using this style in the 1950s.
As the development of vehicle suspensions in the middle of the century continued the traditional barrel type shock add on between the chassis and lower controlling arm or mechanism changed dramatically with the introduction of “struts” which encompassed a number of suspension components into one unit comprising od the shock absorber as the central section with the coil spring surrounding this and the traditional stub axle at its base. This was a revolutionary advancement in suspension design allowing better ride with increased performance handling and braking ability. The majority of vehicles today are manufactured with this style of suspension and shock system. This style of suspension is used both front and rear on front wheel drive vehicles. Future developments to the shock absorber existence now incorporates the addition of a gas to the units allowing a greater degree of control of the movement of the units, traditionally called “gas struts”.
Moving into the 21st century we now have computer controlled suspension with multiple sensors in our automobiles receiving information and controlling the associated responses. Again Monroe developed a “Continuous Control electric Suspension’ for the likes of Mercedes Benz, BMW,Lexus and Audi motor vehicles, this utilises steering sensor, body, and wheel control sending information in the form of milliseconds. This is recognised as one of the best operational suspension control systems in the world.
Impact of worn Shock absorbers
The obvious impact of poor performing shocks is the vehicle feeling less controllable, perhaps a spongy, soft and springy ride allowing a greater degree of roll when cornering at speed and when not stopping in a straight line. One of the noticeable things will be uneven tyre wear, with ‘Flat spots” developing across the tyre, associated with this will be an increase in tyre noise due to the uneven wear of the tyre, this is a common result with tyre shops often encouraging vehicle owners to replace shock absorbers when purchasing new tyres. So although you might think that your shock absorbers aren’t too important, it is evident that when your Shock Absorbers fail they have a knock on affect and begin to cause unnecessary wear to other components of your vehicle.
Standard and Performance applications
There are numerous types and styles of shock on the market readily available to either enhance the performance or maintain the existing performance of any vehicle. When Upgrading your Shock Absorbers in the search from improved handling and performance you need to keep in mind that to increase the performance values of any vehicle will change the characteristics of that particular unit with corresponding changes such as a harder and more stiff ride. These changes that you have made should be balanced with changes in wheel diameter and tyre size associated with increasing the width of the vehicle track to assist in making the ride as comfortable as possible while still improving the overall handling and performance of the vehicles driveability.
Combination of upgrading springs and shocks
It’s a common practise to embrace different variations of spring and shock upgrades to achieve better or a greater control in more severe motoring conditions. The 4wd enthusiast often raise the ride height of the vehicle coupled with either adding additional shock absorbers and or increasing the toughness of the units as well as increasing the strength of the spring, to give a firmer and more controllable ride for the vehicle. You can only imagine some 4wd enthusiast testing their units to the maximum in gullies and rivers, a sure test of any shock absorber.
On the other side some are more interested in lowering a vehicle for better handling and a lower overall centre of gravity. When Lowering a Vehicle it is important that the Shock Absorbers are also changed to a shorter shock to ensure the travel and comfortability of the vehicles handling is still maintained. There are many different options when both lowering and raising a vehicle and it is essential that the correct parts are fitted in conjunction with one another to ensure maximum life span and performance from the products.