In for a Shock
By Kevin Clemens
The top of the line in shock absorbers is the external-reservoir design. These shocks, primarily designed for ultra-high performance and racing applications, use a small, lightweight shock body that is connected through a hose to a reservoir of oil mounted in a different part of the vehicle. The goal of an external reservoir shock is to:
External reservoir shocks are very expensive and are really only needed in extreme high-performance applications.
- Reduce the weight at the wheel for better handling.
- Provide better cooling for the oil in the reservoir.
- Provide significant air space within the reservoir so that the hot oil can expand without blowing out seals.
- Allow superb adjustability as the oil flows to and from the shock body.
When to Buy Shocks
Shock absorbers last a long time, but they tend to degrade slowly throughout their life. So when is it time to replace them?
Shocks can be tested on a shock machine, but to do so requires them to be taken off the car. With labor rates what they are, if your mechanic already has the old shocks off, it makes sense to put new ones back on.
- In some cases, a seal will rupture. A shock covered in oil is a good indication that it has failed.
- The age-old test of bouncing on a fender is really only a rough guide as to whether your vehicle needs new shocks.
- Usually the slow degradation in your shock absorber's performance won't be noticed until it affects handling fairly dramatically.
- Depending on how rough your roads are, modern shocks can last 80-100,000 miles, but remember that a shock with 60,000 miles on it won't perform as well as a new one.
Replacing worn-out shocks can revitalize the handling of a vehicle, returning much of the crispness it had when new. When combined with a new set of tires, a high-mileage vehicle with sloppy handling and a bouncy ride can be transformed.
Which Ones Are Right for Me?
Choosing which shocks to buy largely depends upon what kind of vehicle you own and the kind of driving you do.
As with most automotive components, it is important that you buy the right shocks for your specific vehicle, since mismatched shocks can drastically affect handling and could even be dangerous. The best advice will probably come from a mechanic who is familiar with your type of car. It goes without saying that if you make the right choice, the improvements in your vehicle's ride and handling can be shocking!
- Shocks are available in a range of prices. Often you get what you pay for.
- If you liked the way your vehicle rode and handled when it was new, go with original-equipment replacements.
- If you are looking for more, there are a variety of options open to you, including heavy-duty shocks for carrying heavy loads and performance shocks for crisper handling.
Kevin Clemens has both undergraduate and graduate degrees in engineering and has authored several patents. A former Product Public Relations Director for Michelin Tires and Technical Editor at Automobile Magazine, Kevin writes for European Car and other publications when not competing in rallies in various parts of the world with his vintage automobiles