Buying a car trailer might seem like a straightforward task: find one that fits your car and your budget, hand over the required dollarydoos and drive off into the sunset with your car strapped to the back, ready to make a whole bunch of new friends.

First published in the June 2022 issue of Street Machine

However, there are myriad trailer designs and factors to consider before you burn your hard-earned on something that might not be legal or suit your intended usage.

Budget and space will be the overall deciding factors for what type of trailer you wind up with. We’d all love an enclosed, airbagged and electric-winch-equipped tri-axle rig with a leather sofa and bar, but you still have to be able to pay for it, have a large enough vehicle to haul it, and have somewhere to park it when you’re not using it.

Kiro Aceski from Austrailers has been building trailers since 1985, and has seen a massive uptick in people wanting car trailers built. “In the old days, there weren’t so many car trailers, but now we can’t build enough,” he says.

“They’re stronger and better quality now compared to the old days. We can build 4.2m or up to 6m in length, but you can’t go past 2.5m wide due to laws for fitting in lanes.”

When it comes time to commit to a trailer, the first step is to get some stats for the car you want to haul. Put a full tank of fuel in the car and get a weighbridge ticket so you know exactly how heavy your car is, and take measurements of its overall length, the distance between the outside of each tyre, and the distance between the ground and the bottom of the driver’s door.

Knowing your car’s weight will ensure you buy a trailer with the correct GVM rating, which sets the maximum weight the trailer is rated to haul. Similarly, knowing your vehicle’s overall length and width means you’ll buy a trailer with enough space to fit it, while knowing the door height will let you check you can still open the doors once the car is on the trailer – don’t laugh; this has bitten more people than you think!

Most cheaper trailers are rated to a 2000kg load, and with a trailer itself weighing between 700kg and 1000kg, you could be running uncomfortably close to the three-tonne load limit for many ordinary vehicles. And that is before you add in tools, spares and the like.

“Make sure the trailer is rated for the load you need to move; that is everything,” says Kiro. “You can have bigger trailers built, but they will be heavier, so you might need to have electric brakes or a bigger tow car with a higher rating to haul it.”

You might think opting for electric brakes on any car trailer is a no-brainer; Kiro prefers to look at each trailer, tow car and load as a package. “If you have a lighter trailer with a small car, then maybe you don’t need electric brakes,” he says.

“It will depend on what car is towing the trailer, what car is going on the trailer, and the trailer itself. Sometimes mechanical brakes might be fine, or you may need hydraulic brakes on the trailer.”

Most car trailers will run traditional leaf suspension, though in recent years torsion-beam and air-suspended trailers have become popular options for more expensive set-ups.

Leaf springs are the most budget-friendly option for hauling heavy loads; the set-up costs for airbags are much higher, as they feature more components and a more labour-intensive build.

Kiro cautions against going too cheap with trailers, and he’s seen plenty of people not properly think through how they’ll use their trailer. At the other end of the spectrum, he also points to safety issues of going too large.

“A tri-axle trailer can handle bigger loads, but you really need a truck to pull it,” Kiro says. “Tri-axles become difficult to turn in tight corners, as it will want to push the tow vehicle straight, so they can be dangerous in the wet with a light tow vehicle. Plus you’ll need electric or hydraulic brakes, and that adds to the cost.”

While the science behind car trailers can seem daunting, getting a good result really comes down to the quality of your prep work. Just remember to cover the trailer under your insurance policy, as they go missing more often than they should!