17/06/2026
DO YOU REALLY NEED ELECTRONIC SWAY CONTROL?
While Electronic Sway Control (ESC) is now standard equipment on many new caravans and new model tow vehicles, is it the answer to your stability concerns?
Firstly, I strongly recommend the fitting of ESC on all larger caravans as an extra safety feature. However, it should not be relied upon in place of basic safe caravan towing practices.
WHAT IS ELECTRONIC SWAY CONTROL?
In basic terms, ESC is fitted to the caravan and senses any unusual swaying of the caravan and automatically applies the caravan’s brakes to hopefully reduce or eliminate the caravan sway motion. It is similar to the driver applying the caravan override brakes, in the case of popular Redarc Tow Pro, by pressing the brake adjustment k**b in the driver’s cabin. However, the ESC acts much quicker, and in some cases before the driver realises they have a problem.
Many units will, when sway is detected brake all the caravan wheels simultaneously, while others like the Al-KO systems (Tow Assist and Dexter systems) brake each left or right-side wheel brakes independently or proportionally similar to an ABS braking system in a car. See the Al-KO web site for more details on system types and functions.
Similar systems are now standard on many tow vehicles when towing, however functionality and compatibility with other systems fitted as standard equipment or after-market add on to caravans under tow by those vehicles vary, so please read your vehicle owner’s manuals or speak with the vehicle dealer for specific information about the systems in your tow vehicle and caravan, if fitted.
THE PROBLEM
Too many drivers have stated that they love their ESC, and they can feel it cutting in all the time.
May I say, “IT YOU CAN FEEL THE ESC CUTTING IN ALL THE TIME OR EVEN FIND IT A COMMON OCCURANCE, THEN YOU MAY HAVE A SERIOUS PROBLEM WITH YOUR CARAVAN RIG.”
ALL ESCs are reactive and only cut in when a problem / sway has been detected. They DO NOT stop sway from happening in the first place. Many are highly efficient, depending on how they are installed, and brakes adjusted etc.
In normal driving situations, your caravan should not sway when set up correctly and loaded correctly. That is when basic safe towing practices are being followed.
Sway is usually caused by several factors coming together at the same time.
Almost all caravans can be towed at speeds below 70kph without any issues. It is above this speed (approximately) that other factors will come into play.
A badly loaded caravan is one of the major contributors to the caravan swaying. Too much weight on the rear and a low tow ball weight will often be a big factor in sway starting as speed increases.
Once sway has started, a heavy load on the very front or very rear of the caravan will act as pendulums as the caravan yaws over the axles increasing the inertia of the swaying motion.
Incorrect tyre pressures on the tow vehicle and caravan will also contribute to the lack of caravan stability at this time impacting the tyre side wall’s rolling action affecting further sway movement.
Side winds from natural weather events, or from passing large vehicles can also start sway motions. We have all sat in our cars at the traffic lights when a large truck passes and our car rocks to the side caused by the air dam in front of the truck and rear suction as the truck passes.
Uneven road surfaces can also rock your van from side to side and wheel ruts in the roads can steer your van from side to side as you drive.
It is when you are in a sway event that you will appreciate having a tow vehicle heavier than the caravan / trailer under tow. I do refer to actual weight not perceived or plated weights, as a heavy object will always push around a lighter object. We do not want a heavy caravan to be pushing a lighter tow vehicle from side to side.
When driving down hill, the caravan may start to push the tow vehicle causing it to start swaying.
While one of these factors alone may not start trailer / caravan sway it is when two or more of these factors come together in, what I call, ‘The Perfect Storm,” sway can start quite suddenly.
WHAT ARE SOME CONTRIBUTING FACTORS TO CARAVAN SWAY?
o INCORRECT LOADING OF THE CARAVAN, LOW TOW HITCH WEIGHT.
o SPEED INCREASE’S THE CHANCE OF SWAY EXPOTENTIALLY
o SPEED INCREASES THE SEVERITY OF SWAY AS INERTIAL INCREASES
o MISMATCHING TOW VEHICLE AND CARAVAN – WEIGHTS, SET UP, ETC.
o TYRE PRESSURES
o TOO LOW TYRE PRESSURE CONTRIBUTES TO UNDERSTEER
o TOO HIGH TYRE PRESSURERS CONTRIBUTES TO OVERSTEER
o HEAVY WEIGHTS AT EXTREME FRONT AND EXTREME REAR OF THE CARAVAN
o CROSS WINDS FOR SUCTION FROM WEATHER OR PASSING VEHICLES.
DOWN HILL DRIVING. TRAILER TRYING TO OVERTAKE THE TOW VEHICLE.
Your caravan should self-correct when these situations are encounter. If it does not, then you may have some issues with your set up that need addressing.
IN MOST CASES, SWAY IS THE SYMPTOM AND RESULT OF NOT FOLLOWING BASIC SAFE TOWING PRACTICES. THE SYMPTOM OF A PROBLEM.
FIX THE PROBLEM, NOT THE SYMPTOM.
While we all have the best of intentions, it is a fact that many vans sway for reasons unknow to the driver. It is therefore recommended to have ESC fitted to your caravan for these occasions.
DO NOT however expect ESC to stop all sway as the towing companies still recover caravans that have rolled over that had ESC fitted to them.
It can be an extra safety feature, not a substitute for not following basic safe caravan towing procedures.
For much more reliable information on towing your new caravan safely and legally get your copy of SAFE CARAVAN TOWING – THE MANUAL
It is available in E-Book version and printed hard copy posted anywhere in Australia including P.O. Boxes.
AVAILABLE FROM THE TRUCK FRIENDLY WEB SITE AT –
https://www.truckfriendly.com.au/safe-caravan-towing-the-manual/
It makes an ideal gift for those you care about who are new to caravanning, or for Mum or Dad’s birthdays, Christmas or Father’s or Mother’s Day.
What’s Up Down Under described it as “The New Towing Bible”, in their Nov ’24 review.
Also available at the Truck Friendly site at upcoming caravan expos in Tamworth, Rockhampton, Fraser Coast, Toowoomba, Lismore and Newcastle.
Love to hear your feedback.
Stay safe.
Cheers
Ken Wilson
Truck Friendly caravan road safety program
[email protected]
