Un-sprung Weight, the Enemy that Became a Friend

For years racecar designers and automotive suspension engineers have sought to keep the un-sprung wheel/axle component weight of a vehicle suspension and axle system to a minimum. In the early days, ultra light Magnesium wheels were considered a big break through. In the mean time, because we strived so hard to reduce un-sprung weight, we tended to consider it simply as an “Enemy” that had to be dealt with. So it may be a little surprising that un-sprung mass could actually become useful in controlling dynamic roll or pitch, but it can. Tire footprint stability and body roll recovery during negotiation of “S” bends and chicanes in racing are the key to faster times through these turns. Because the time element during a cornering maneuver is so critical in racing, common sense dictates that If you can control or shut down the initiation of roll by a few milliseconds, it will make a big difference to the momentum and thus lessen the total amount of roll generated and needed to be corrected by the stabilizer system. This says that good rebound travel control can seriously enhance recovery.

This Paper outlines a newly patented rebound control method intended both for racing and street use that utilizing the un-sprung weight.