Parabolic springs appear to be the new kid on the block but in actual fact have been used by the majority of vehicle manufacturers for many years and are still the choice for heavy trucks and personnel carriers. They are chosen for their comfort and ability to carry heavy loads.
An older style multi-leaf spring is made up with 6 to 8 leaves of reducing lengths to try to provide a reasonably comfortable ride but with the capability to handle heavy loads, the big problem is that light or heavy loads the entire 8 or so leaves are clamped firmly together and therefore are not able to flex when necessary to give a comfortable ride! The Parabolic spring leaves are quite thick in the centre where they bolt to the axle and gradually taper to the end of the leaf. This 'Parabolic' shape allows each leaf to act as a spring in its own right without necessarily touching another leaf. There are generally two main leaves and a lower one to cope with heavy loads.
This arrangement allows the suspension to articulate, (to keep the wheels on the ground) be easier on the driver, and still retain the ability to carry a heavy load without comfort being compromised as in a conventional multi-leaf set-up.
With the advent of coil springs Parabolics were discontinued for a period of time in passenger cars. Now with modern steel combined with state-of-the-art heat treatment Terrain Tamer are able to offer a lighter, flexible, quieter and more comfortable suspension system ideally suitable for today’s multi-use four-wheel drives.
We’ve been testing these units for a long time now and they have exceeded all our expectations. (As we say, make mine Parabolics on the rocks thanks).