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