How to choose the right tow vehicle

It's not easy shopping around for the right tow vehicle, particularly when you’re not going to find many car dealers that will let you hitch up your caravan to a demo for a test drive.

While we can help with our dedicated towing tests, which provide a good idea of how a vehicle tows in the real world, there are also technical specs that provide clues as to whether a vehicle is likely to be a towing hero or not.

The best tow vehicles aren't great around town

Like everything, you will have to make compromises when choosing a tow vehicle. A big, heavy 4WD might tow really well but be hard to live with during the daily urban grind. Yet if you’ve got a big, heavy van, a nimble city car isn’t going to cut it.

So what do you need to look for in a good tow vehicle?

What will ultimately make or break towing rig balance is load placement, but there are a few tow vehicle specifications that will indicate whether it’s likely to be a stable platform to start with.

You want as long a wheelbase as possible and as short a rear overhang as you can find for better towing stability. If you have a tow vehicle that’s short on wheelbase and has a long rear overhang (and/or has a towbar design that has the towball sticking out for miles) it’ll allow the caravan to have more leverage to make the vehicle yaw (sway).

Live axle is preferable

A live rear axle is usually stronger and more consistent for load carrying than an independent suspension design, particularly when you’ve got the combination of a heavy towball download and a loaded vehicle.

Because the live axle is tougher (and more often than not fitted to load-carriers like utes), there's usually a higher axle load limit than independent designs.

Generally speaking, tyres will wear more evenly with a live axle than with an independent set-up when under load because the wheel’s relationship to the road never changes. That isn't always the case with some independent suspensions, as they can end up causing accelerated tyre wear with negative camber when compressed, such as when towing.

With leaf-spring rear axles, there are fewer bushings to wear out too, and those there are – because of the tougher nature of the suspension application – tend to last longer.

Go overboard in towing capacity

Caravans are only getting heavier as buyers demand more features, but you should be realistic about the vehicle’s maximum towing capacity. It’s not worth loading a van so it's as heavy as the vehicle can tow down to the last kilogram. You need a safety margin, and you might need to pay for it with a bigger, heavier and more expensive tow vehicle.

It's always a good idea to buy a vehicle with as much towing capacity as you can get, even if you don’t think you’ll ever need it. Even if your van won’t ever weigh more than 2300kg fully loaded, buying a 4WD with a 3500kg maximum capacity makes sense. Generally speaking, the vehicle will have more power in reserve and more weight to make it a more relaxed towing platform. It’ll also give you some leeway if you upgrade to a heavier van later.

Try to buy a vehicle that has 10 per cent towball mass (TBM) download capacity (of maximum towing capacity). Don’t assume that the vehicle you’re considering does have the 10 per cent TBM, as not all do.

Two examples come from Mitsubishi and Nissan. The Mitsubishi Pajero has the 10 per cent TBM – but only up to 2500kg. If you’re towing between 2500kg and 3000kg with a Pajero, TBM is reduced to 180kg.

A number of Nissan vehicles have a reduced TBM when the vehicle is at or near maximum GVM. For example, the Y62 Patrol TBM maximum is 250kg at GVM; reduce payload by 130kg and maximum TBM is 350kg (and therefore 10 per cent of the Y62’s 3500kg towing capacity).

It might be better to opt for a vehicle with a slightly lower tow rating but higher TBM, like the Ford Everest.

Make sure tow ball mass is sufficient

Some manufacturers have a very low TBM download capacity – much less then 10 per cent – either because the vehicle’s manufacturer discovered during development that the towbar or the chassis was not up to the job, or it was engineered that way for markets (such as Europe) where high TBMs are not necessary.

European vans only require up to five per cent TBM, so some European vehicles can have as little as an 80kg TBM maximum.

Don’t forget that TBM is part of the vehicle’s payload, and also a proportion of the vehicle’s rear axle load. These have to be factored in your towing weight calculations. Better to discover these won’t work for your van (by looking at the vehicle’s tech specs) before rather than after the purchase.

Tow vehicle should match trailer weight

Generally speaking a vehicle will tow better if it's heavier than the caravan it's towing. While many vehicles are perfectly legal towing a trailer weighing more than they do, don’t assume you can load up the heaviest, biggest caravan you can buy and that the 3500kg-rated vehicle will tow it like a champ.

Dual-cab utes are the main culprits here; most weigh not much more than 2000kg but some are rated to tow 3500kg. Some are really good tow vehicles, but a heavy van will more easily become unstable if the much lighter tow vehicle has to swerve to avoid an obstacle, for example.

Also, don't forget to check the towbar’s towing maximum if you’re buying used. Tow bar capacity can sometimes be rated lower than the vehicle’s maximum towing capacity.

Ladder frame chassis is good for towing

Even though the separate chassis is really old school in the passenger car world, commercial vehicles still use this design for a reason – it's typically stronger than a monocoque body. That doesn’t mean monocoque is bad (the long-lived Pajero is a case in point) but for heavy hauling a separate chassis, only found on large 4WD wagons or utes, is the best bet.

Diesel grunt preferable for towing

Whether you should buy a diesel or petrol tow vehicle comes down to many factors but generally the diesel engine has better load-lugging torque and is much more efficient.

Towing a heavy caravan puts a lot of load on an engine and while a petrol engine of large displacement and with good torque output will handle it comfortably, it will consume a lot of fuel doing it. You can expect at least 50 per cent more fuel use when towing a full-size heavy van with a six- or eight-cylinder petrol engine vehicle than when travelling solo.

The modern turbo-diesel engine is the best compromise for towing, with its strong mid-range torque that makes towing relatively relaxed. The added bonus is fuel consumption will be better than a petrol vehicle, with only perhaps a 25 per cent higher thirst than when cruising without a van.

The only negative with a diesel is the potential for expensive repairs if it gets a dose of contaminated fuel. The injectors and fuel pump of high pressure common-rail diesels don’t cope well with that.

What makes a good tow vehicle?