Towing Off-Road

Towing Off-Road

Towing Off-Road

by Gerald O’Brien

Hooking up a trailer or caravan and towing it is one thing, getting it right and doing it properly is another. All too often the latter is overlooked and the problems which occur as a result thereof are often picked up when it’s almost too late.

Towing whilst off-roading will quite often present an entirely different reaction to a vehicle or trailer than being towed on the road with the exact same set up and rig. One example is trailer sway. Trailers do not really sway whilst being towed off the road due to lower speeds, but may have extreme sway the minute it hits the tarmac – so much so that it becomes dangerous to drive normally, let alone taking evasive action in an emergency situation.

What are the problems and how do we sort them out?
The most common problem that I came across over a number of years, and not always the fault of the trailer owner, is the downward weight placed on a tow ball or goose neck (draw bar)once the trailer is hitched up. The vertical weight placed on a goose neck should be a maximum of 120 kilograms. On one hand if the vertical weight is too low it may cause sway and on the other hand if it’s too heavy it will have other adverse effects. If you can load the hitch by hand, with a bit of a struggle you will get close to the perfect weight. Ideally, one should try and have it at around 60 to 80 kgs. Many of the newer tow bars fitted actually state the maximum permissible vertical weight for that particular tow bar. The vehicles hand book will also have the maximum vertical weight. This may vary slightly between vehicles.

The reason why the correct weight is so critical lies in the fact that if the weight is too heavy, there is too much weight on the vehicle’s rear suspension thereby causing the vehicle to stand nose high and experience the possible effects of under steer. Aside from the poor handling of a vehicle that is nose high, it also has a critical effect on the vehicle’s braking system which can end in disastrous consequences. Too little weight has the opposite effect on the vehicle. Too little weight may in fact cause the vehicle to dip down in the front, thereby reducing the weight on the rear axle. This may lead to vehicle sway and very poor handling, especially whilst cornering, and of course have a critical effect on the vehicle’s breaking system.
Some trailer/caravan manufacturers also seem to have their axles on certain models a little too far to the rear, thereby making it very difficult to balance the load correctly. There are ways of checking the vertical weight. Firstly, the trailer’s tow hitch weight must be measured at precisely the same height that the trailer’s tow hitch would be when hooked up and ready to go with the vehicle. Once you have that height, you may use a bathroom scale and a piece of wood that is cut to the right length to measure this. The other option is to get a fisherman’s scale that goes up to around 100 kgs and measure it that way. If the measurement height is to high, the weight reading will be too low and the opposite for the other way around. If the trailer is not level when hooked up and you cannot get the desired weight right on the hitch, first see what you can do about getting the trailer as level as possible. Once this is done, see what you can do about the weight distribution when loading the trailer.

The vertical limits are there for a good reason and I have witnessed a few bent and broken towbars when this has been exceeded.

The next cause of trailer/caravan failure is due to the lack of proper maintenance. How often do we go on an extended off-road trip through one of our neighbouring countries covering thousands of kilometres and when we get back the vehicle goes in for a service with instructions issued to have a good look at it since as it has been on an off-road trip? What happens to the poor trailer? It immediately gets parked until the next trip and is expected to perform the same once hooked up again. Don’t be surprised if it doesn’t!

We have already discussed the level of the trailer, but besides the weight issue; if the hitch is too low, it may very well cause drag in the “middelmannetjie” leading to all sorts of traction problems. Driving over ridges may cause damage to various parts when getting hooked up and forcing the vehicle and trailer across. Try and get the trailer as level as possible and you will have a much safer, more enjoyable trip.

Tyre pressures on the trailer may be lowered slightly from the norm. The trailer’s tyres are merely trailing wheels with no drive and as such are not subject to the same harsh conditions as the tyres on the vehicle towing it. Slightly lower pressures will cause less bounce and shock going through the trailer and all the additional equipment in it, such as fridges that would prefer minimal shaking and movement.

Like many things in life, what you put into it before hand is what you get out of it later on. Therefore, my advice would be to make an effort to maintain your trailer or caravan properly as you would with your motor vehicle.