Tested: AirSafe hitch

Three years ago when I purchased my current caravan I headed into Vehicle Components in Brisbane to get them to give the suspension, one of their own ‘LT’ systems, the once over.

One of the mechanics who had a good deal of experience building trailers, strongly advised me to do something about the tow bar set up on my Isuzu NPS 300 4WD truck as the rear leaf spring suspension as standard was too hard.

This coupled with the fact that the distance from the centre of the rear wheel to the hitch was around 750mm longer than that on a typical tow vehicle such as a Toyota Landcruiser, increased the vertical travel distance of the caravan hitch and amplifying the jarring transferred through the drawbar to the van chassis when going over road imperfections.

During the first month of travel his advice was always in the back of my mind; never more so than when opening the door to a van floor strewn with broken crockery that had ejected out of cupboards after doors had jarred open.

Ceiling light covers were torn loose and LED light panels scattered about, glasses smashed in cupboards, wardrobes emptied onto the floor… it was mayhem and seemed only a matter of time before those mechanic’s words, “you’ll break the chassis on this van if you don’t do something about it”, would be realised.

So I seriously considered the options. One was to change the springs, which I had intended to in order to get the truck level when carrying a maximum load. While an air bag suspension would have solved all the issues, the $10,000 plus outlay was out of my budget.

I opted instead for new leaf springs from Queensland-based Dynamic Suspensions that helped soften the ride for the caravan and got the truck level, but more intervention was required.

This came from Boronia Towbars in Victoria with the US-imported AirSafe hitch. I paid $2400 for this model with free freight (that saved me a few dollars as it weighs 42kg). The AirSafe takes the place of the typical Hayman Reese tow bar tongue, and its tongue can be adjusted to multiple positions to match the height of the caravan.

It’s held in place with six hi-tensile bolts, and our tie rods connect the upper section to the lower section with a 100lb (45kg) air bag to keeps those sections apart. A shock absorber on each side further softens the travel.

Once the unit is set up, the air bag is inflated to lift the upper section, which allows approximately 20mm between the nylon stoppers on the underside of a frame extending from the bottom section and the top of the upper section while the tow weight is on the pin.

The tie rods should also be parallel to the ground. Set up to tow my air bag pressure sits around 60psi.

I was relieved to find this installation improved the tow performance of the van. I regularly check the chassis anyway and all is well in that department but now there’s no need for a full scale clean-up of the inside of the caravan even after extended towing on rough tracks.

The only downside I’ve found is the inflation valve for the air bag sits proud of the top of the unit with no surrounding protection. As a result when the truck’s tail gate slipped out of my grip, it swung down and broke the valve stem off, necessitating a braze welding job to repair it. I’ve fixed a piece of aluminium angle to the top plate to prevent this occurring again.

Other units available perform a similar function but use a different method. One I’ve seen uses a tow bar that’s spring loaded and the full width of the bar rises and falls as required.

A friend of mine has fitted another type to his Ford F-250 that swings up and down, buffered by rubber pads. However, he’s found that the caravan shunts forward and back about 25mm due to the angle and distance of the arc of travel of the tow pin, which is disconcerting as he can feel this through the body of the vehicle.

I can recommend the AirSafe hitch though, to anyone with a similar issue to mine when towing their trailer.