After nearly 40,000 kilometres of rough, loaded 4×4 touring, Grant and Linda Hanan review their Terrain Tamer Parabolic leaf springs. Here’s how it went!
Parabolic leaf springs aren’t anything new and have been widely used within the trucking transport industry for years. And it’s for a good reason they’re so popular, as their design handles weights from heavy to light and everything in between. However, when it comes to the 4×4 sector, it’s only been within the past decade or so that Australian companies like Terrain Tamer have offered these types of springs to suit some popular utility models.
So, what’s so good about parabolic leaf springs? When you take a look at a set, they differ from the multi-spring pack in a couple of ways. Let’s start with the most noticeable feature, the base spring at the bottom of the pack. The centre of this spring is much thicker and decreases in thickness the further you follow it to its outer edges. You’ll find this results in a tapered profile. This single leaf alone can cope with a high degree of load and varying force applied to it when compared to a multi-leaf spring pack that distributes the load over multiple leaf springs.
Additional leaf springs are then added to a parabolic set-up to assist when a higher constant load is needed. These additional leaf springs have what’s known as “military wrap” at the fixed end of the spring, where they’re rolled around. The idea here is to provide improved safety for off-road conditions. Interleaf poly blocks and silencer pads are then added to reduce the friction between leaves to offer a softer ride and less noise.

Our first-hand experience
Before we swapped out our 10-leaf semi-elliptic leaf pack to some Terrain Tamer parabolic springs a few years ago, you could say the body roll from that old Toyota suspension constantly made us feel like a tinnie being chucked around in a swell. It’s fair to say we were happy to get rid of the old leaf pack and try something different. When we first fitted that three-leaf parabolic springs pack and did a review for Unsealed 4×4 a few years ago, that was the only pack Terrain Tamer was manufacturing at the time. Designed to carry 0-400 kilograms, we gave that suspension a really good workout while towing a camper. We travelled just shy of 10,000 km through the Kimberley and Northern Territory on a mix of terrain including bitumen, sand, dirt and rocks.
We found the three-leaf set gave us a better ride and improved handling, most notably the reduction in body roll on bitumen. It also did a good job at low speeds/low range when driving off-road. The parabolics flexed well and absorbed the conditions with minimal fuss. However, we did find we needed some assistance from the airbags because of the amount of weight we carry when long-term remote touring. Our setup isn’t the lightest going around, and we recognised we needed further suspension adjustments to cope with our heavier loads.
Switching to heavier-duty parabolic leaf springs
Whether it was purely coincidental or a stroke of good luck, Terrain Tamer released a four-leaf parabolic spring set just after we got back from that trip. It was perfect timing, so we headed back to the shed to swap out the three-leaf pack and give the four-pack a go. There was no question that the four-leaf pack that’s designed to carry 400-700kg would suit our setup better.


Our testing ground for this next trip was up the blacktop on the Stuart Highway before turning off to head across to Birdsville via the Simpson Desert. Then it was back south along to Googs Track before heading west and returning home via some Nullarbor and coastal roads. That trip was diverse and a good mix of sand, gravel and rocky tracks with some bitumen highways thrown in.
How did it go?
So how did it go? The highway driving results with the new four-leaf parabolic springs were pretty similar to the three-leaf. And the Simpson crossing didn’t pose any issues, with the suspension absorbing the ups and downs of the sand dunes quite well. No problems with gravel road travel either. We experienced two occasions where we bottomed out along the Googs Track, but we put that down to having the camper in tow and the condition of the track. It was very rutted out in places, and some deep wombat-style holes made the camper act like a bit of a boat anchor at times.
There was one occasion when we disconnected the camper to head off exploring and noticed a big difference in suspension travel, and it didn’t bottom out at all. So, having that extra leaf did a good job carrying our load, although we noticed the ride was a bit stiffer than the three-leaf pack. As they say, everything’s a trade-off, and things are still heaps better than our original OEM 10-leaf set.

What we think about Terrain Tamer’s four-leaf parabolic springs
The four-leaf Terrain Tamer parabolic set is now on its way to 40,000 kilometres. Every 5,000 kilometres, we service the suspension by greasing all the bushes via the grease nipples. We also wipe in grease to the plastic stays to reduce friction between the leaves. So far, the suspension is holding up well, and there aren’t any signs of the bushes degrading or needing replacing. We have noticed the plastic stays show signs of wear and will likely need replacing within the next 50,000 kilometres. The interleaf spacers and silencing pads are also worn slightly but are all in good working order.
When you’re travelling on road conditions comprising salt-swept mining roads, harsh gravel, clay-like mud or fine sand dune country, and then throw in a couple of water crossings, it all takes its toll on any undercarriage paintwork. And parabolic leaf springs are no exception. We stay on top of things by periodically applying a coat of chassis paint to all the underside components, including the parabolic springs set. We see it as a way of prolonging the life of the components and keeping any rust away for as long as possible.
After fitting that four-leaf set, it was a good opportunity to replace the shockers as well, which still appear to be holding up okay.


What next?
So, the current configuration of our parabolic leaf spring suspension setup is serving us well. The only change we may make going forward is to upgrade our shockers to a remote-style adjustable set. We reckon this will be the perfect setup to improve ride and handling throughout varying load-carrying conditions. But we’re in no hurry, and that can be a job for down the track.
By Grant and Linda Hanan