We pressure tested Terrain Tamer Parabolic Springs

By Mark Allen 8 Min Read

The short answer as to whether I still have my Terrain Tamer parabolic and Smart coil suspension kit on my Troopy after three years is: YES. Am I happy with them; absolutely… YES. Would I swap them out for regular semi-elliptic leaf springs and non-linear coils… hell NO.

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There’s not a chance anyone could prize this suspension kit from me. It really is that good and to think I’d part with it is downright laughable.

Ya’ see, these parabolic leaves hold weight better than my previous couple of test leaf-suspension kits. They offer increased comfort, improved ground clearance under the U-bolts, lighter weight, and superior flex off-road. So that makes them a winner all round.

Creating the perfect ride

I installed the three-leaf parabolic leaf kit in the rear about three years ago. A four-leaf version was then swapped in, given my need to tow the camper trailer and the caravan. Plus the need to pack the whole family into the cavernous Troopy for our outback excursions. While the three-leaf pack was adequate for running empty and moderate loads, the higher-rated, four-leaf kit was needed for all the heavy-duty work the Troopy is used for.

I also swapped from the standard valved expanded-body Terrain Tamer shock absorbers to the firmer valved kit. This was to help control the big buses’ body roll on and off-road.

There’s no argument here that the resultant ride comfort, performance off-road, control on-road and ability to carry weight, along with the tow ball weight, is amazing. Moreover, it’s a system that I’d wager no other leaf spring setup could match. Given the parabolic’s perform both unladen, fully loaded and every variant in between.

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Parabolic leaf springs
I changed from the standard rate valved shocks to the firmer rate to help control the Troopy © Mark Allen

What is the Terrain Tamer Parabolic Leaf Springs pack?

For those who aren’t sure what a parabolic leaf pack is, you’ll want to grab a pen and paper for this part. First thing is know is that each leaf within the pack is tapered from thicker at the centre to thinner at both ends. Each leaf acts like a variable or progressive rate spring. The same goes for the front-end Smart Coils; they are tapered or reduced in coil diameter from top to bottom to return that variable / progressive load ability. The more weight you add to the leaves and the coils, the firmer they get. Not to mention the more load they can handle. The only comment I have for this is that it’s simply incredible.

As with everything, there is an element of upkeep. However the only I’ve needed is to tend to the greaseable shackles with a pump or two of grease. This has only been from time to time. Full-stop, that’s all. Amazingly, nothing else has required touching. Even the shackle and shock rubbers were in perfect condition at the time of swapping leaves and shocks. So they were just left. 

Terrain Tamer Parabolic Leaf springs
Note the lower load leaf is a long way off touching the rest of the pack; it doesn’t come into play until well loaded © Mark Allen

A hard life

Let’s face it; suspension hides under your vehicle. It’s not shiny or pretty and tends to be forgotten until it fails. I’ll admit, I may be… well, definitely am… a little different to most regarding mechanical parts on my vehicle. Every time I walk past my Troopy, I check that it’s sitting evenly on flat ground. I also check the rubber pads still separate the leaves, the shackles have the correct deflection, and everything looks as it should. I don’t wash my Troopy too often, even less the suspension. While it’s neglected, I keep an eye on it all.

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My Troopy gets punted around the countryside on all track surfaces, towing at high to medium speeds, as well as low-range crawling through sand, mud and ruts. Yep, I’ve been known to take the wrong line from time to time and have been bogged. My suspension certainly hasn’t been spared all in the name of keeping it looking pretty. While I don’t believe in crashing, bashing and deliberately damaging my vehicle, if I need to get somewhere, I’ll do my best to succeed! 

One time, I took my eye off some bright white dunes and missed the drop-off, to crash over the edge and force the front coils up to the bump stops. Dreading the damage, I sheepishly looked under the front end. To my delight, I found that everything was straight and in alignment. While a bit of luck no doubt played a part in saving damage, I put it down to the Smart Coils progressively rated design and the valving of the shocks to save the day – thank goodness.

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Sandbag testing

As a controlled testing system, I loaded 750kg of sandbags into my Troopy. I wanted to see the on and off-road drive testing, when compared to standard original equipment, and an aftermarket semi-elliptic leaf pack with non-progressive front coils. I found that the Terrain Tamer kit certainly comes out on top. What further confirms the merit of using this system is the advantages of a much lighter leaf spring pack and improved ground clearance given the shallower depth of the pack at the U-bolts. I also can’t forget to mention its improved flexibility off-road, and improved on-road performance. You truly couldn’t ask for more than that!

Terrain Tamer Parabolic Leaf springs
At full compression, each leaf is still independent of the others, resulting in an improved ride and performance © Mark Allen

The next three years… And beyond

I’m definitely not suggesting this suspension kit will only last another three years. Regardless of its ultimate longevity, it would take one hell of a reason to swap them out for anything else. Sure, the Terrain Tamer adjustable shocks look attractive, and they would certainly help in some situations, but for the type of use my Troopy sees, I’m happy sticking with the expanded body shocks.

Since my upgrade to the four-leaf pack, Terrain Tamer has introduced a heavy-duty mining kit. Will I be using it? No, I won’t. It’s simply too heavily rated for my needs. Plus, they have also developed kits to suit most popular dual cabs and delving into older LandCruiser models, making for an easy suspension choice should you steer any of these vehicles.


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