David MottonSee other Advice articles filed in ‘Tow cars’ written by David Motton
Tow Car Editor
Nobody wants it to happen.
Responsible caravanners take steps to make sure it doesn't happen.
But once in a while when towing a caravan it does and, if and when it happens to you, you'll need to be ready for it.
We're talking about the dreaded snake.
What is snaking when towing a caravan?
Guaranteed to dry the throat and moisten the palms of the most experienced caravanner, snaking is when the caravan starts to move from side to side while towing.
Scary stuff, but with the right preparation and sensible driving a snake shouldn't occur.
Even it does, so long as you know what to do, any competent driver should be able to bring their car and caravan back under control.
Prevention is better than cure
The best way to cope with snaking is to make sure it doesn't happen in the first place.
There are lots of steps you can take to make instability while towing less likely.
As well as staying within the car's legal towing limits, ideally the loaded caravan should weigh no more than 85% of the kerbweight of the tow car.
Matches of up to 100% are considered acceptable for experienced tow car drivers, but the heavier the car is relative to the weight of the caravan, the more stable the combination should be.
How do you load yours?
It's not just weight that's important, where that weight is carried matters, too.
Keep heavy items in the car (as close to the rear axle as possible rather than near the bumper end of the boot) or put them in the caravan low down and close to the axle.
If you load heavy items at the back of the caravan they can act like a swinging pendulum, making it tougher to bring any side-to-side movement under control.
Check the noseweight (the download through the towing hitch onto the towball). Ideally it should be between 4% and 7% of the caravan's laden weight, but don't exceed the permitted maximum load on the towball.
Electronic towing aids
Technology can also help you.
Many modern cars have advanced stability systems which recognise when a car is towing and act to quell any snaking. These go by various different names, including Trailer Stability Assist and Trailer Sway Control.
Often, modern caravans have stability systems of their own. Al-Ko's ATC (Automatic Trailer Control) is the most common one, and applies the caravan's brakes if it begins to sway.
For caravans with a BPW chassis, the equivalent system is IDC (Intelligent Drive Control).
Check before you buy your next caravan to see if such a system is specified. If not, either system can be retrofitted to a compatible chassis.
Drive well, stay safe
The 'prevention is better than cure' approach should continue after you set off.
Take it easy on the speed when towing. The legal maximum is a limit not a target, as your driving instructor probably told you.
If the weather is bad, especially if the wind is high, 55mph in the inside lane can feel a lot more stable than chopping and changing lanes at 60mph.
Be especially cautious driving at speed down a steep gradient. Be ready to change down a gear so engine braking can help you keep to a sensible speed.
Be doubly wary heading downhill on a windy day. If your speed creeps up and a sudden strong gust catches the caravan, this is when a snake is most likely.
However, so long as you are driving sensibly and the caravan is loaded well, there's no reason a snake should occur.
Of course, towing a caravan demands your full concentration, but stay relaxed rather than tense at the wheel.
Every slight shimmy or gentle nudge from the caravan isn't a warning that the tourer is about to get out of control.
The car is always trying to pull the caravan straight, so don't keep making lots of small movements at the wheel in an attempt to correct every slight bump or bobble behind you.
Lots of fidgety steering corrections will actually make the car and caravan more nervous. Let the car do the work for you.
How to cope with a snaking caravan
Let's say that despite your best efforts, the caravan begins to snake.
To start with, you'll see the caravan grow larger in one mirror, then the other. You'll feel the back of the car beginning to move with the caravan, and you'll be gently rocked from side to side in your seat.
Don't panic. Don't start sawing at the wheel to correct the movement.
And despite what some may tell you, don't try to accelerate out of the snake as this could lead to a higher speed accident. You shouldn't hit the brake pedal either, as you could lose control.
Instead, gently back off the accelerator. Keep a light grip on the wheel and keep it pointing straight ahead.
Now comes the really hard part. The snaking motion could get worse before it gets better. With each swing the caravan could loom larger in your mirrors and you'll have to fight the urge to brake or steer.
The next two seconds could seem like half a minute, but have faith that you are doing the right thing. The swaying motion will gradually ebb away, and the car will pull the caravan straight again.
Take a deep breath, and ask yourself why the snake happened.
If you were travelling too quickly for the conditions, then take it easier for the rest of the journey. If you loaded the caravan poorly, then adjust the loading as soon as it's practical and safe to do so.
Pull in at the next services and treat yourself to a cup of tea or coffee. You'll need it.