What is called a shock absorber offers as many variables in the handling of a car as questions asked on how to deal with them. I have spent more than 20 years gaining knowledge of their functions, exploring their limits and mastering  their use by tuning and re-designing them for a wide range of applications.

Today, I am sharing with you my knowledge in the hope of supporting your understanding of what can be achieved with this ‘magic wand’ of motorsports. To start with, lets do a little history of the modern racing shock. 

What is known as the shim stack valving and the pressurized shock started in the late 1950’s with the French company De Carbon who patented this new concept for high volume production. In the racing version, this shock was equipped with a rebound adjuster enclosed in the shaft and accessible under the eyelet. This is the same as the one seen on the modern shocks of today. The first company to take advantage of this design was Bilstein who paid royalties and carried the logo “Patented by De Carbon” during it’s years of production.

In the late seventies, Fox began producing race car shocks based on the De Carbon design. An important feature was added to help the compression control setting and reduce heat build up in the shock body by creating an external reservoir. This new characteristic was created as an extension of the shock in order to receive the excess hydraulic liquid from the compression of the shaft inside the main body. In the original concept, a nitrogen chamber under a floating piston at the bottom of the shock was compressed by the excess volume. The external canister containing the nitrogen chamber also allowed for better control of the liquid flow and consequently an external adjustment of the compression forces.

Monroe was the next company involved in developing the De Carbon and Fox concepts and went  even further by adding engineering support at race events with an expert technical staff and a van equipped with a sophisticated dynamometer.

Koni also developed a new generation of shocks in Europe based on the same principles of shim stacks with a nitrogen chamber contained in the main body. Another adjuster was added to the main body with one adjuster for compression and one for rebound and both adjusters based on high speed control (shaft speed).

When Monroe decided to leave the racing business, Penske took over that department and started diversifying the concept by adding more products, more applications and a wider range of adjustment capabilities. Other companies also began developing new shocks with various characteristics for control and adjustment. Quantum was one of the first manufacturers to concentrate on using the adjusters for a wide range of low speed control (shaft speed) which represents the most significant range of handling on the cars.

Many other companies arrived on the market with variations on the same principles at approximately the same time. Today, Ohlins, Dynamics and JRZ are sharing the market with Koni and Penske. There is also a list of companies manufacturing shocks based on less complicated designs that offer good products for the money and are used mainly on circle track and drag racing vehicles. 

The potential for shock control is proportional to its refinement but also directly related to the cost. Nevertheless, an expensive part does not guarantee better results unless a level of understanding can be applied that takes advantage of today’s sophisticated technology.

Next time, we will look at what makes what and what you can do to start taking advantage of the black magic of shocks.