What is a trailer used for?

Material on the hook

Anyone who buys a trailer wants to use it as versatile as possible. But the wide range makes the decision difficult. We recommend proceeding systematically and give practical tips for choosing the right trailer.

Matthias Fischer

The most important question for joiners, joiners and window fitters who want to buy a trailer is first of all: What should be transported? If, for example, mainly high-quality pieces of furniture are transported, a luggage tag is recommended. But if there are many other areas of application, tradespeople have to find a compromise and are more likely to resort to an all-rounder.

This could be, for example, the tried and tested flatbed trailer, which also allows material to be transported that exceeds the length of the vehicle, but which can also be upgraded to a weatherproof means of transport with a tarpaulin and bow.

The next criterion is the weight of the load. If large and heavy loads are to be transported, the trailer must have an appropriate payload. On the one hand, the question arises whether a single-axle or a two-axle vehicle is more suitable and, on the other hand, whether the trailer should be braked or unbraked.

If only smaller or light objects need to be transported, a trailer with a total weight of up to 750 kg may be the right choice. With an empty weight of around 150 kg, such trailers have a payload of around 600 kg.

If large loads of over 3000 kg, for example, are to be pulled, the towing vehicle also comes into play. It must have a trailer load that allows the new trailer to be used. That in turn depends, among other things, on the weight of the tractor.

Information about the possible trailer load can be found in the registration papers. An entry in Part 1 of the registration certificate also provides information on how much braked or unbraked load the vehicle is allowed to pull. By the way, cars with trailers may only be driven by people with a class B driving license.

Can you also have one more axle?

In carpentry and joinery businesses there is actually a lot to be said for the trailer with two axles. Such trailers usually have a higher payload, they run more quietly and are less sensitive to driving over ruts. What speaks in favor of single-axle vehicles, on the other hand, is that they are much easier to maneuver, have a lower dead weight and are usually much cheaper to buy. In principle, it is not only practical when parking, but also when coupling, if the trailer can also be moved with muscle power - which is usually much more difficult with two-axle vehicles.

Well sprung, safe on the road

Good shock absorbers and spring elements are decisive for safety and driving comfort, because they allow the vibrations of the sprung masses to subside quickly.
Incidentally, the shock absorption is not used to absorb bumps in the road. This is the job of the suspension. Shock absorbers dampen the body vibrations of a trailer and keep the tires safely on the road when cornering or when braking hard.
Vibration damping is integrated so that the wheels do not rebound automatically after compression. As with a car, the wheels would otherwise lose traction in the event of a sudden rebound and the trailer would slip or bounce

Better braked or unbraked?

Braked trailers are more expensive, but offer significant advantages. So z. B. spared the brakes of the towing vehicle and the braking distance is shortened. Another advantage is that the trailer cannot break away so easily in the event of an emergency braking. Therefore, the approval authorities or the vehicle manufacturer often have restrictions for unbraked trailers. Mainly smaller and lighter vehicles are only allowed to use their full trailer load with braked trailers.

Why it is worth buying quality

As is so often the case, quality is an important criterion. Many providers have special professional trailers on offer, which are usually of significantly higher quality and therefore have their price. But as in the handicraft in general, quality pays off, especially when it is used frequently. Paying attention to the last cent when buying a trailer is therefore certainly wrong.
Because if a particularly “inexpensive” trailer has too few or too weakly dimensioned fastening eyes, the load can often only be insufficiently secured. And if the worst comes to the worst, the damage is usually greater than the investment in corresponding features.

In terms of ease of repair, high-quality trailers also do better than the inexpensive variant from the hardware store or the discounter.
With such tightly calculated minimalists, the side walls are often quite thin. Flaps and connecting brackets are also often poorly dimensioned. As a result, many models twist quickly, especially in the tough everyday work of a craftsman.

As materials for trailer constructions in professional quality z. B. hot-dip galvanized steel, aluminum or a combination of steel and wood.

Top speed - where do you want to go?

There are trailers that are only allowed to move at 80 km / h, and others that are approved for 100 km / h. The latter are a bit more complex and therefore more expensive to buy. But a higher investment can pay for itself quickly, especially on longer journeys, because the driver is faster on the road and is more likely to drive to the customer's premises - not to mention the driving comfort on the motorway, where experience has shown that you are only too happy to travel at a speed of 80 km / h is overtaken by trucks.
If, on the other hand, the trailer is only in town and on short journeys, the 80 approval may be completely sufficient. Because the 100 mark is only valid on motorways and motorways anyway. On the country road, the speed limit with a trailer is always 80 km / h.

Give rubber: important information about wheels and tires

An important safety aspect is the tire size, because sudden steering maneuvers can cause a trailer to stand up and, in the worst case, even tip over. The higher the trailer weight and the larger the tire circumference, the lower the tendency to tip over. When it comes to trailers, the age of the tires is often not considered very carefully. But especially with trailers that are moved at 100 km / h, the tires must not be more than six years old. At the latest at the TÜV, fun is over. In addition, they must have at least the speed index L (120 km / h). Incidentally, a trailer does not necessarily have to be equipped with winter tires. The legislature only provides such an obligation for motor vehicles. However, for reasons of safety, the ADAC recommends voluntarily equipping trailers with winter tires.

Checklist and practical tips for used vehicles

Buying a used trailer can also be the right choice. So that you don't have any scrap on the hook, you should pay particular attention to the following points.

  • TÜV: Was the trailer during the mandatory general inspection and is there a corresponding sticker? The examination intervals for trailers are between twelve and 24 months, depending on their weight. Trailers with a gross vehicle weight of over 3.5 t must be inspected annually from the first start-up. Trailers with a total weight between 0.75 and 3.5 t have to be inspected every two years. If the permissible total weight is less than 750 kg, the first TÜV is due three years after the initial registration. After that, this trailer also has to go to the HU every two years. Despite having a valid sticker, you should check every trailer for defects.
  • Electrics: The wiring harness should be checked for fixed installation and that the insulation is free from damage. The 7- or 13-pin connector that connects the trailer's electrics to the car should also not have any damage or patches. With 7-pin plugs, only the basic lighting functions are transferred to the trailer, i.e. lights, brake lights, indicators and rear fog lights. With a 13-pin plug, in addition to the basic lighting functions, reversing lights, a permanent positive cable or a charging cable can also be transmitted.
  • Construction: If the trailer has a tarpaulin, this should be examined for possible breaks and cracks. The fastening rubbers are ideally still elastic and not worn out.
  • Brake and support wheel: Braked trailers have an additional parking brake. Their mechanics must move freely and be undamaged. The wheels should lock when the brake is applied. It is also advisable to look at the jockey wheel and hand crank. The wheel must not buckle when pushed and should turn smoothly. It must be easy to move the crank up and down.
  • Flaps and clutch: Dented flaps are difficult to close. The lock should therefore be checked for ease of movement as well as for existing securing options. At best, the trailer coupling itself is greased on the inside and must lock securely on the coupling hook - without play. Of course, the breakaway cable, which triggers the overrun brake in an emergency, must not be damaged.
  • Basically, the purchase of a used trailer, as well as a motor vehicle, is a matter of trust and a reputable dealer is probably the safest choice with a wide range.

At a glance

Advantages of different variants

Suitcase tag …

... have a solid box structure and offer a wide range of possible uses. A solid structure is ideal, especially for the transport of high-quality or sensitive products, because the contents are protected against theft and the effects of the weather. In addition, the side walls offer an ideal advertising space for the company. Bright interior lighting is important here in order to be able to load or work safely in the dark.

Flatbed trailer ...

... are the all-rounders among the trailers. Various expansion options can be created with the appropriate accessories. The bows and tarpaulin significantly increase the transport volume and the goods to be transported are largely protected from the elements. Reffs for the safe transport of components such as doors and windows can also be installed on flatbeds. Important: Extendable supports ensure a safe stand when loading and unloading.

Dump truck ...

... can be quite useful in some situations. On the one hand, they can be used like an open flatbed trailer. And if, for example, building rubble has to be disposed of during a renovation, unloading at the disposal site is many times faster than by hand. Tipper trailers are available in various sizes and as three-way tippers or rear tippers. It is important that the hangers are secured against tipping over.

You can find more information about variants, manufacturers and a lot of interesting information here:


The author

Matthias Fischer is a freelance specialist journalist
with over 25 years of industry experience - many years of which as a deputy
Editor-in-chief of a construction magazine.

BM online S1 | 2017