How does towing a trailer affect car behaviour?

In this blog post, we will answer the following question: How does towing a trailer affect car behaviour? We will give you essential advice on towing a trailer safely, including how to choose the right car for towing, what equipment you may need and how to avoid unwanted experiences. 

How does towing a trailer affect car behaviour?

Towing a trailer will most certainly affect car behaviour, but if you take the necessary precautions, nothing bad will happen. Before deciding to tow any trailer, make sure that your car is in good working order. Brakes, coolant and oil levels, and the quality of your tires are important things to check. With a visit to your mechanic, you can confirm that your car is in optimal conditions for travel and towing.

To keep your car+trailer safely on the road, follow these simple tips:

  1. Make sure the weight of the trailer is correctly distributed: too much weight towards the front of your trailer can exert too much force on your car’s suspension and the trailer hitch, while too much weight at the rear of the caravan can destabilize it. Therefore, it is important that you distribute the load correctly. 
  1. Secure the assembly well: Whether it is the roof box, the trailer or the caravan, be sure to follow all the safety instructions. If in doubt, contact customer service or the reseller of the relevant equipment.
  1. Respect the towing limits: An overloaded roof box, a trailer that carries more than it should, and you put yourself in danger. Not only you but also other road users. Be careful not to overload this equipment.
  1. Adapt your driving style: Be careful, you do not drive the same way with or without a roof box or a trailer. The wind resistance is different, so is the time required to brake … A vehicle towing a trailer close to its weight takes twice as long to stop. You should anticipate and reduce your speed. Although no specific limitation exists below 3.5 tonnes.
  1. Braking, less is more. It is important to keep your distance and to anticipate so that you know how to stop in time. Excessive pressure on the brakes is strongly discouraged. When going down hills, such a manoeuvre leads to overheating them and thus losing their effectiveness.

Additionally, learn to use the electric brakes and adjust the controller that operates them. Remember that the slightest pressure on the brake pedal of your vehicle also puts pressure on the electric brakes of the trailer. Do not touch the brake pedal unless you intend to use them.

Towing a trailer: what you must know

Towing a trailer sounds simple, doesn’t it? We put a hitch in, connect the trailer to it, and then we go, right? The appearance of your vehicle alone does not guarantee its ability to tow a trailer, even if it is equipped with a hitch.

In fact, a hitch can be fitted to any vehicle, but there are several factors that go into determining a vehicle’s towing capacity. Everything is based on Newton’s first law (the principle of inertia): A body at rest tends to stay at rest, and heavy objects are more difficult to move. 

So a moving object will tend to stay in motion, while heavy objects will be more difficult to turn or stop. Also, before towing a trailer, you must consider the capabilities of your vehicle to do so, the equipment required to do so and your ability to drive in such a case.

The right vehicle to tow a trailer

When choosing a car to tow a trailer, the engine’s horsepower and torque seem like a great place to start. Virtually any vehicle with around 400 lb-ft (542 Nm) of torque can pull over 9500 lbs if not much more. Pulling a trailer with your car, truck or SUV isn’t all about horsepower and torque.

Consult your vehicle’s owner’s manual to find the Combined Gross Weight Rating (GCWR) to get an idea of ​​its total towing capacity. The manual includes not only the weight of the vehicle, trailer and its load, but also that of passengers, baggage and other objects on board. All vehicle components are designed to support such a load: the frame, chassis, suspension, steering, engine, gearbox, cooling system and brakes.

The right equipment to tow a trailer

In addition to the trailer hitch, your vehicle may require additional equipment, even more if it was not specifically designed for it. Vehicles designed for towing are usually equipped with a trailer hitch attachment . You will need a ball and a drawbar to attach the trailer to the vehicle. 

The trailer light connector should be near the hitch. Some vehicles have mirrors that extend out or have adjustable mirrors to provide good visibility around the trailer. These vehicles designed for towing often have more powerful brakes and an additional transmission cooling system.

If the weight of the trailer and its load does not exceed the GVWR, there are some additions that could allow you to tow a trailer: auxiliary coolers to prevent the gearbox from overheating, mirror extensions to improve visibility and more powerful brakes to increase braking efficiency. For heavy loads, a load distribution hitch or air suspension can keep the vehicle level, improving stability.

Towing and driving assistance

In addition to the famous towing packages offered by the manufacturers – which mostly include a sturdy hitch, harnesses for lighting, a larger capacity radiator and oil coolers – Safety and driver assistance are now added to the options available to allow safe towing of a trailer. 

Anti-lock braking, traction control, stability control, to name a few, now combine to help the driver better control the towed load. Several manufacturers, Ford for example, offer a trailer stabilization function that uses commercial vehicle stability control in symbiosis with traction control.

All of these devices often act without our knowledge and in silence, but they can make all the difference between a successful trip and a mishap.

A few tips for safe towing of a trailer

  • When towing a trailer, the driving behaviour must be adjusted to the size and weight of the load. Indeed, this exerts strong stress on the chassis of the towing vehicle, so any manoeuvre – turns, changes of lane, accelerations and, above all, decelerations – must be done smoothly.
  • Many have already had the unpleasant experience of a loss of tension on the drawbar, commonly called “pole”. The phenomenon occurs on a descent, during sudden deceleration. The trailer, out of control, then takes a completely unexpected direction, and the ensuing sway, more or less marked according to the weight of the trailer, can lead to a swerve.

Under these circumstances: first, keep calm. Then accelerate to restore adequate tension on the drawbar and regain control of the trailer. Obviously, the sequence happens very quickly and demands nerves of steel from any driver. The golden rule is therefore to completely avoid this kind of mishap by keeping a suitable cruising speed and remaining vigilant!

It is also essential when towing a trailer, to maintain a greater distance from the vehicle in front of us. Indeed, the two to three seconds usually recommended should be increased to three or four, and even more, if the trailer is carrying a heavy load.

  • We also recommend that any driver who must tow a trailer for the first time –  or who uses a type of trailer he is unfamiliar with – familiarize himself with the behaviour of his vehicle before embarking on a long trip. Reversing manoeuvres, steeper turns and driving on the highway require you to get to grips with the reactions of the towing vehicle.

The owner’s manual provides a host of very relevant tips on towing, some of which include maximum speed.

Conclusions

Don’t underestimate the challenge of driving a vehicle towing a trailer. In addition to the technical aspects to consider regarding the vehicle and the trailer, you will need to adapt your driving behaviour when you attach any object larger or heavier than a bicycle rack to your hitch. The acceleration will be longer and you will need a greater stopping distance. 

You will need to leave enough space between your vehicle and the one in front of you. You will also need to make wider turns than usual to avoid colliding with other vehicles, hitting sidewalks, trees or pedestrians.

Driving a vehicle with a trailer takes practice. First, try towing an empty trailer down a less busy road or into a parking lot. Get used to the distances and space needed to move safely. Driving in reverse requires special skills and you will need to practice a lot to get it done. Again, parking lots and deserted areas are perfect places for this. Finally, when you first hit the road, take it easy to get used to the way the vehicle reacts to that extra load. 

Please feel free to contact us if you have any questions or comments about the content. 

FAQ on How does towing a trailer affect car behaviour?

Can towing a caravan damage your car?

Towing a caravan will not damage your car, as long as you respect the maximum allowed mass that a vehicle can tow. A load heavier than the limit imposed by the manufacturers will result in exceeding the towing capacity of the vehicle to pull and stop the load, and could result in altering the structure of the towing vehicle, the chassis or causing an accident.

Can you increase a vehicle’s towing capacity?

You can’t increase a vehicle’s towing capacity as they are engineered with a specific capability. Some cars weren’t designed for towing at all!

How do you tell if you are towing too much?

You know that you are towing too much if you are over the GCWR and if your vehicle is leaning, or there is lots of bounce when you hit bumps along the road.

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