Tag Archives: Regressive damper


5 Feb



The trickle down theory may not quite be a perfect operation in public policy, but in the Motorsport world, it certainly holds true. Technological developments born on the track eventually find there way to our daily road cars.

The rage among higher end “reasonably priced” coilovers of the past several years has been the idea of digressive valving. Simplified, its a damper (shock) where the rate of damping force decreases as shaft speed increases. In a traditional damper the damping force increases as shaft speed does. The harder the shock works, the stiffer it gets. Digressive slows this curve down, to better allow the tires to maintain grip and life the harder the car is pushed. as developments on both tire and aero continue, the need and desire for a next generation shock became apparent. I say reasonable in quotes because its a very variable term.

Penske is forever at the forefront of damper technology. Their units can be found in every professional starting grid the world over. NASCAR to GT and everything in between. One of their developments in the last few years has been with regressive valving. This shock works by actually dropping the damping force as shaft speeds increase. In doing do, you are essentially controlling the oscillations the damper would normally experience after it hits a jarring bump. Like the candy canes on a track for example. This lets the spring be controlled more efficiently, keeping the tires planted. The more the tire footprint stays on the ground with an equal level of force acting upon it, the faster the car is. You can brake later, turn faster, put the throttle down sooner. In past setups, on order to maximize the use of downforce, both via front splinters and/or rear spoilers, very high rate springs had to be used. Without them the car would get pushed to the ground…literally. When a super stiff spring is being asked to be controlled by rapid shaft speed, you are forced to dial in very high rebound rates, which in turn kills tire life. But with this new regressive valving, Penske has found they can control the chassis better by dialing in reduced rates of high speed damping force, with increased rates of low speed force. So now instead of that kerbing tossing your 140 mph car airborne, or sideways, it’s better able to remain planted. The former speedbump becomes more akin to nothing more than a pebble.

Now, these are still at their relative early age of development, but with the I created top speeds and aero designs of modern road cars its only a matter of time before this stuff finds its way to the typical sports car/sedan.