Parabolic Springs

Terrain Tamer Parabolic Leaf Springs are designed for the ultimate ride quality.

Traditional 4WD leaf springs are often thick, heavy, uncomfortable and loud, offering little to no flex. In response to this Terrain Tamer developed their 4WD Parabolic Leaf Springs, applying a carefully researched design and modern technology to a well-established idea from the trucking industry.

Containing fewer leaves than regular leaf springs, they are named for their tapered ‘parabolic’ design - thicker in the centre and thinner toward the ends, eliminating the weight of traditional leaf packs and dramatically reduces the unsprung weight of the vehicle and making them safer both on the road, and in the workshop. This lower weight also creates a more comfortable ride, whether loaded or unloaded, addressing the varying and ever-changing applications of the modern 4WD parts.

The design helps the spring to flex while still providing the strength needed for heavy loads, particularly useful when challenged with difficult terrain, as the flex afforded with a Parabolic Spring allows the spring to give a little when the driver hits a bump in the road, reducing the shock transferred to the crown wheel and pinion, stopping the wheel from spinning and essentially maintaining safety and drive.

The new shape also provides better axle articulation, and almost no interleaf friction, allowing the spring to compress or extend with ease without touching until there is a reasonable load on the vehicle, which means the springs are quieter and also helps minimise issues with rust build up, which can be a major cause of failure in standard leaf springs.

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Utilising new technology on an old design, the parabolic springs allow for a comfortable ride whether the vehicle is fully loaded or empty.

  • Lighter – Less unsprung weight
  • Less Shock – Less shock load on the differential gears
  • Quieter – The leafs do not touch each other
  • Comfortable – With better articulation
  • Strong – Exceptional load carrying capability

What is a Parabolic Spring

Parabolic Leaf Springs typically contain fewer leafs than traditional leaf packs and get their name from their tapered “parabolic” design, meaning they are thicker in the centre and thinner at the ends. Already a well-established idea in the trucking industry, Terrain Tamer have applied their own carefully researched design and modern technology, and use a special grade steel to develop their range of Parabolic Leaf Springs specifically for 4WD vehicles.

How do Parabolic Springs work?

Traditionally heavy linear leaf packs can also be uncomfortable and loud and can create a safety issue, as they offer little to no flex, meaning that when a driver hits a bump, or finds themselves in a rough offroad situation, the rigidity of the leaf pack will cause the opposite wheel will lift, spinning and losing traction, ceasing drive and effectively endangering the driver. In a Parabolic spring, the tapered design of each leaf allows the stress to be distributed more evenly across the spring, and each leaf is allowed to work independently with enhanced flex without sacrificing load capacity, and keeping all four wheels on the ground.

What are the advantages to Parabolic Springs?

This design of Parabolic Springs eliminates the weight of often heavy, thick, traditional leaf packs and dramatically reducing the unsprung weight of the vehicle, essentially freeing up the weight needed for practical use. This lower unsprung weight addresses the issue of GVM limits, and also acts to create a more comfortable ride when the vehicle is unloaded, accommodating the varying and ever-changing applications that the modern day 4WD is used for, freeing up weight for towing heavy loads, carrying tools or touring with the family, and ensuring it is comfortable whether empty or loaded. The Parabolic shape also provides better axle articulation, as well as almost no interleaf friction, allowing the spring to compress or extend with ease without touching each other until there is a reasonable load on the vehicle. This feature means that the springs are not only quieter, but it also acts to help minimise any issues with rust build up, which can be a major cause of failure in standard leaf springs.

Do Parabolic Springs offer better flex?

The Parabolic design allows the spring to flex while still providing the strength needed to bear the weight of heavy loads. This is particularly useful in 4WD applications that carry excessive load on the driveline, or when challenged with difficult terrain, as the flex afforded with a Parabolic Spring lets it give a little when the driver hits a bump in the road, allowing the differential housing to rotate with the springs and effectively providing a smoother ride, reducing the shock transferred to the crown wheel and pinion, stopping the wheel from spinning and maintaining safety and drive. The same force with a standard leaf pack would almost certainly cause more shock to the vehicle and driver.

Para...what! with A.G. from TT

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).

Allan.G.