10 Aug, 2023

Tough Dog 4WD Suspension: Developing specific suspension systems for RVs

by Ian Bellert

Caravan World knows how important it is to have a great suspension set up on your tow vehicle. What about your van or trailer? We caught up with Tough Dog 4WD Suspension to find out how the team is developing a suspension system that works with your vehicle, not against it.

After 38 years of producing 4WD suspension systems, the Tough Dog recently worked with Signature Camper Trailers to develop a specific suspension system for Signature’s Hybrid Camper range. Let's see how the partnership developed and the difference a specific suspension setup makes to how a trailer handles under tow.

First up, we spoke with Simon Vella who is the Product Development Director at 4Way Suspension, the company behind Tough Dog. Giving some background to the process, Simon commented, “We were able to draw upon 38 years of experience in the 4WD sector, both locally and overseas to produce a specific suspension setup for Signature Campers Hybrid van. It definitely was not a case of pulling a 4WD shock from the shelf and bolting it on. Our experience has taught us that every vehicle, van or trailer has different requirements. The variables we considered included trailer weight, the geometry of the suspension set up on the trailer, the intended use of the trailer and how to develop a suspension system that works effectively across a wide variety of road and track conditions.”

Simon Vella, Product Development Director at 4Way Suspension

Mark Nisbet, the Managing Director of Signature Campers was able to share further insight into how the process developed. “We had done a few 4WD trips with the Tough Dog team and what really impressed us was the amount of work that went into setting up their cars,” Mark said. “Some campfire chats led us to discussing how we could set up a camper trailer to behave the best it possibly could, both on-road and offroad.”

“What people don't realise is how much a trailer can control a car when it's moving around. Working with Tough Dog, we identified what needs to be changed in a shock and the whole suspension system to make the trailer more compliant under tow,” Mark added.

Mark Nisbet, Managing Director of Signature Camper Trailers

“We discussed the different behaviours of the campers while being towed. The differences between the heavier versus light trailers. We developed information around towball weights, compression rates and importantly, rebound rates. Rebound rates have much more effect on the trailer than compressions. It took us a few months and a lot of kilometres traversing rough tracks, fire trails and long stints on the blacktop to work out the best setup.

“The results have been so impressive now we have the Tough Dog suspension as standard across our Hybrid range,” Mark concluded.

Digging deeper

To find out more, we asked Simon from 4Way Suspension and Tough Dog about the factors that went into developing the suspension setup for Signature’s Hybrid suspension.

“When developing a range of suspension systems for the RV market, we know that every project is different. We do the same extensive testing for a hybrid camper, camper trailer or caravan, as we would do for any new vehicle,” Simon said. “In this instance our first focus was on fine-tuning the shock absorbers and playing around with the shim stack. Throughout the testing process, we would change out the shocks multiple times a day. It was essential that we monitored the heat range of the shocks under load and ensured the geometry of the trailer, including the bump stops and the limiting straps, all worked within sequence. And within the shock length as well. The process to develop was huge. We took a lot of time to make sure the product developed was 100 per cent right.

“With the Signature Campers Hybrid, we were able to fit a shock absorber with a 60mm casing within the space we had. The Signature Campers Hybrid has four shocks, two per control arm and it's a lot of damping capacity which certainly irons out the bumps.

“We altered bump stop heights and tweaked a limiting strap to work well with the shock. The shock on the Signature Hybrid is well protected in its function. Which means the shock is not exposed to full top-out or full-bottom out in the cycle. If a shock becomes the limiting factor in the suspension set up, then the shock will wear, the ride will be poor and negatively impact the tow vehicle.”

A key component

One key component used in Tough Dog’s shock absorbers is rubber bushes on the shocks, used on the top and bottom.

“The bushes we've developed over the past 20 years are an hourglass shape. This allows the bush to pivot in the metal eye-ring of the shock absorber. This reduces side loading the shock. Side loading impacts the ‘rod-seal’ inside the shock absorber and can affect the long-term life and performance of a shock absorber. The shock is free to move around within the rubber and not pass pressure from side loading through the shock and into the bearing. The bushes are fully serviceable, enhancing shock life as well,” Simon explained.

Speak with the specialists

What about other RV manufacturers that want to improve the suspension on their products?

“We have a program that can tailor make shocks for the RV market to perform in the Australian conditions,” Simon said. “We have been playing around in that sector for quite some time in the background, including in the motorhomes and camper trailers segment. With Signature Campers, it's the first time we’ve come out and promoted the work we have done together in developing a suspension system specifically for a manufacturer's platform.

“We get the shock lengths right, get the valving right, match the correct bore size, fluid and foam configuration and have the engineering knowledge to develop the right solution for any trailer.

“Tough Dog 4WD Suspension has no limitations in what we can offer anyone wanting to develop a complete suspension system for any trailer. We specialise in developing suspension systems for brand new vehicles and are focused on doing the same for RV manufacturers. It’s a natural progression for the Tough Dog team.”

The suspension setup and the quality of the components used, allows Tough Dog to provide a four-year warranty on its suspension setups.

If you are considering a new van, hybrid or camper trailer, make sure you check out what’s underneath and make sure it's going to work with you, not against you, on the road.

For more information check out toughdog.com.au, call (02) 9672 8899 or check out the explainer video below.