How to choose a good tow car

Choosing a car can be hard enough, but if you want to tow a caravan, horsebox or trailer, then the decision gets a lot more complicated.

A car that performs just fine on the daily commute won't necessarily have enough oomph to comfortably pull a caravan, and a small and light car might not be heavy enough to feel stable with a heavy trailer behind it.

Fortunately, help is at hand. Here's what to look for when choosing a tow car.

Stability matters most

Imagine you are towing downhill. There's a strong crosswind blowing. You look in your mirrors and see the caravan starting to sway from side to side in your mirrors.

In towing circles this is called 'snaking', and it's not a pleasant experience. If the caravan doesn't come back under control it can lead to a serious accident.

The best way to deal with a snake is to prevent it from happening in the first place. The more stable your tow car (and the more sensible your driving) the less likely it is that a snake will start.

Lots of qualities contribute to a car's stability. One of the most important is how the car weighs relative to the the caravan or trailer it is towing. This is sometimes referred to as the matching ratio. The Camping and Caravanning Club recommends towing a caravan weighing no more than 85% of the car's kerbweight, especially if you are new to towing. This is sometimes called 'the 85% rule', which is a little misleading as it's not a legal requirement. But as a rule of thumb it has served caravanners well for many years.

The upshot of the 85% guideline is that, all else being equal, a heavy car will be more stable than a light one towing the same caravan or trailer. Go too far the other way, with a light car and a heavy trailer, and you risk the tail wagging the dog.

However, it would be too simplistic to state that just because a car is heavy it will be stable while towing. Many other factors come into play, including the the distance between the front and rear axle, how well controlled the ride is, and whether self-levelling suspension is fitted to keep the car level when heavily loaded.

It's hard to be sure that a particular make and model will make a stable tow car just because it drives well in everyday driving. So it's worth checking out our 2021 Tow Car Awards winners, which will be revealed this afternoon.

You should also check that the car can legally tow whatever caravan or trailer you plan to match it to. To find the legal limit, take a look in the sales brochure, the handbook, or check the car's VIN plate.

Electronic aids can help

If you've chosen a stable tow car and you drive it carefully, then touch wood you won't experience a snake. But if you do, it helps to have a car which will work with the driver to bring the caravan back under control.

Any electronic stability system should help, but in some cars there are specific systems designed to work when towing. They go by different names (Trailer Stability Assist, Trailer Stability Program, and Trailer Sway Control, among others), but all do much the same job, sensing instability before it becomes pronounced and applying the car's brakes individually or reducing the throttle to bring the car and trailer under control.

We've tried these systems on a number of cars and have found them very effective. So if you are looking for a tow car, check if such technology is fitted.

Towing takes torque

Pulling the weight of a caravan or trailer puts extra strain on a car's engine and gearbox, so it pays to have a punchier engine than you might otherwise be happy with. Check a car's specs for the engine's torque (its pulling power). Measured in lb ft, it's a lot more important than peak power when towing, unless you're prepared to rev the engine close to the redline every time you want to accelerate or hold speed on a steep hill.

The more torque an engine has the better, preferably well spread across the lower and middle rev range (say, 1500rpm to 2500rpm).

For strong mid-range torque, it's hard to beat a good turbodiesel. While diesel power may be steadily falling out of favour with declining sales, there are good reasons to put a diesel at the top of your list if you plan to tow regularly.

The torque characteristics are the most obvious, but diesels also tend to weigh more than petrols, which helps with matching ratios. And fuel economy while towing is usually much better with a diesel than a petrol. If anything, the difference between diesel and petrol economy tends to be more pronounced while towing than in everyday driving.

The benefits of four-wheel drive

Many tow car drivers choose a four-wheel-drive car. It's not essential – plenty of front and rear-wheel-drive models tow very well – but if you plan to tow all-year round in any weather then it's well worth considering.

Even in dry weather, it's a lot easier for a 4x4 to put its power to the road than a front-wheel-drive car, especially with the weight of a caravan or trailer pushing down on the back of the car and unweighting the driven wheels.

What's more, the extra weight of a four-wheel-drive transmission helps with matching ratios, and so contributes to stable towing.

What Car? says...

Stability is the most important quality you can look for in a tow car. As a rule, the heavier the car is relative to what it's towing the better. Electronic aids such as Trailer Stability Control help, too.

If you want to be able to keep up with your own shadow, then choose a tow car with plenty of pulling power. And for anyone who plans to tow all-year round, whatever the weather, four-wheel drive is a definite plus.

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