Useful: retrofitting a trailer coupling! The info!

Thomas Wachsmuth 20 October 2020 Tips, products, information & Co.

Reading time 9 Min.

Recently updated on January 10, 2022 at 08:21 am

If you transport a lot, but space in the car is tight, you can install one Trailer hitch on. This takes less time than you might think and solves the space problems because you can now stow everything in the trailer. In the following, we will explain the different towbars available, explain how to install them and also explain the costs that will arise.

Overview of the topics

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What types of towbars are there?

There are basically three variants of towbars: The rigid trailer hitch, the removable trailer attachment and the swiveling towbar. Let's start with the rigid tow bar: (Back to overview)

A rigid towbar is the perfect choice if continuous use is planned, which is why this option is often chosen by frequent drivers and companies. A rigid towbar is also the cheapest in terms of price. The trailer coupling is used with a welded-on or screwed-on ball rod. As the name suggests, a rigid trailer coupling cannot be removed because the trailer hitch including the ball head device is permanently installed on the assembly cross member. (Back to overview)

Now for the detachable trailer hitch. This option is particularly useful if you only want to use the trailer hitch from time to time. In this way, the vehicle is not permanently changed. Since the towbar is detachable, as the name suggests, you can easily remove it when you don't need it. The advantage of this is that you can still enjoy the "original" look of your car and that the ugly hook doesn't bother you. Please note, however, that although there is no law or regulation stating that the towbar must be removed when driving without a trailer, you still have to remove it if this was noted as a requirement in the type approval or in the vehicle documents. This is the case, for example, when the ball head of the trailer coupling covers the license plate or when driving without a trailer. A little advice: Basically, you should always remove the tow bar when driving without a trailer. The reason for this is that it can save costs in the event of a rear-end collision, since a trailer hitch that is not removed can increase the damage to the injured person's car. In addition, if the towbar is not removed, you could be held to blame, as you have increased the risk of operation, which in turn results in a reduction in claims. (Back to overview)
The swiveling trailer coupling. Of all the variants presented, this is the most practical and at the same time most elegant solution, because a swiveling trailer hitch is extremely inconspicuous. You can easily fold such a towbar under the bumper when you no longer need it and simply fold it out again when you need it. This happens pretty quickly and you also preserve the look of your vehicle when not in use. This option is particularly suitable for anyone who wants to use the trailer hitch spontaneously. The disadvantage is that a swiveling trailer coupling cannot be folded under every bumper and, moreover, is not available for every vehicle. Here it is advisable to simply ask in the workshop whether assembly is possible. If you have installed such a trailer coupling yourself, you should definitely have it checked and entered by a specialist. This way you can be sure that the device is safe and professional. (Back to overview)

Costs of retrofitting the trailer coupling?

The amount of material costs depends on which trailer hitch you ultimately choose, which in turn depends on the load that the trailer hitch should carry. As already mentioned, the rigid towbar is the cheapest option. A rigid towbar costs around 180 to 650 euros. On top of this amount, there are costs of around 80 to 100 euros for the electrical kit required. If you want to leave the installation of the towbar to a workshop, there are also labor costs. One hour costs between 50 and 120 euros, the installation takes about 2 to 3 hours ( depending on the selected variant) - ultimately the labor costs can be between 150 and 360 euros. Some workshops also offer fixed prices for installing a tow bar. (Back to overview)

Which system to retrofit?

It is important that the system fits your vehicle - because not every trailer coupling is suitable for every vehicle. For example, there are some restrictions, especially with electric, hybrid and sports vehicles. It is therefore advisable to retrofit an original system from the car manufacturer. This has the advantage that the component has already been tested and you can also be sure that everything fits exactly and works properly. Furthermore, the vehicle's electrics are matched in advance to the electrical kit for trailer operation. (Back to overview)

When to the TÜV?

Of course, there is also the option of buying a third-party system. The disadvantage here, however, is that often none EC type-approval is available and you therefore have to go to the TÜV to check the system after installation to be registeredsystem. (Back to overview)

7-pole or 13-pole? There are adapters!

You should also find out before buying whether a 7-pin or 13-pin trailer socket is required. This is important for the electrical system so that the turn signals, brake lights and rear fog lights work properly. Otherwise there are also adapters from 7 to 13 pin. In some cases you also need an extra control unit that controls the trailer's electrics and sometimes the electrics for trailer operation must be activated in advance by a workshop. Furthermore, after installing the trailer hitch, the headlight setting should be checked, as the vehicle may well be higher due to the additional weight at the rear. If you have installed a towbar with EC type approval, you should make sure that the installation instructions are in your vehicle. (Back to overview)

Who is allowed to drive a trailer?

If you own one Driver's license are class B, you are allowed to tow a trailer with a total mass of up to 750 kilograms. If the total mass of the car and trailer is less than 3500 kilograms, the total mass of the trailer may also be exceeded as long as the total mass of 3500 kilograms is not exceeded. If you want to tow heavier trailers, you must complete driver training in accordance with B 96. This includes all trailers with a gross vehicle weight exceeding 750 kilograms and which are towed by a class B vehicle. In addition, the maximum permissible mass of the two vehicles must not be higher than 4250 kilograms, which affects many caravan combinations, for example. If you are planning to tow even heavier trailers, this requires a class BE driving license, with the maximum permissible weight of the trailer being 3500 kilograms. Furthermore, the support and support loads must of course be taken into account. (Back to overview)

Can I retrofit a trailer coupling myself?

In principle, this is of course possible - normally, very detailed instructions are enclosed with the system so that the system can be installed properly. Please note, however, that you still need manual skills and the right tools. If you feel confident about the installation and have the right tools, nothing stands in the way of installation on your own, which incidentally takes 2 to 3 hours. However, retrofitting a towbar is not necessarily cheap, which is why it is worthwhile to compare prices, find special offers and choose a workshop that offers fixed prices. When buying a new vehicle, this should of course be taken into account. (Back to overview)

Protect coupling with cover

In addition to a simple cover made of various, mostly water-repellent, materials, there are also various versions made of soft PVC, which are attached to the trailer hitch like a cover. Of course you can now buy the cheapest and simplest version, which will look the same in most cases: small, black and inconspicuous. This will be enough for most drivers, but there are almost no limits to those who want more. Regardless of whether you prefer a skull, a flaming design or maybe a little glitter, you will find it. There is more about this in our separate article on Cover for the trailer couplingsystem. (Back to overview)

universal usability is given

The ball heads of the pendants are standardized so that they can be used universally. (Back to overview)

Trailer recognizing ESP

There are now software extensions that are specially designed for driving with trailers, the so-called ESP recognizing followers, It is intended to help prevent the trailer from swaying or swinging after a steering movement and thus to avoid dangerous accidents caused by rocking. Anyone who frequently travels to camping with an older towing vehicle can certainly ask themselves to what extent it is possible and sensible to retrofit this function in their vehicle. That's why we have dealt with this topic HEREsystem. (Back to overview)

Retrofitting a trailer coupling (AHK), differences, interesting facts, costs - summary information:

The trailer coupling is installed to transport trailers, caravans, bicycles, etc.

A trailer coupling is available as a rigid, detachable / swiveling version (the latter can be removed / swiveled behind the apron and locked when not in use)
Depending on the variant, there are differences in terms of the electrical connection and the type of integration into the vehicle's electrical system. (7- and 13-pin sockets)
A trailer coupling cannot be installed on every car. (the vehicle manufacturer must have specified a support and trailer load for the respective model)

Differences in price of the couplings result from:
- the manufacturer
- the vertical load
- the trailer load
- the removability (rigid, removable / swiveling)
- the power connection (7-pin / 13-pin)
- various comfort functions
- conditions given ex works (Has the vehicle already been prepared for retrofitting? Are there cables already in the trunk?)
Differences between 7-pin and 13-pin electrical kit / trailer socket
- the 13-pin socket has a microswitch and detects trailer operation (Parking aid (PDC) is deactivated, system integration is required)
- if possible, you should install a 13-pin AHK (Among other things, it can also be used to supply a refrigerator in the caravan)
- Tip: There are also Adapter for the power connection from 7 to 13 or vice versa.
The total costs for a high-quality, detachable, 13-pin trailer coupling are between 750 and 1.500 euros including installation, depending on the vehicle model.

The assembly of the trailer hitch
- For safety reasons it is better to have it carried out by a specialist workshop
- Dismantle the rear bumper
- Carry out assembly of the cross member
- Tip: Suitable holes for screwing to the body are usually provided at the factory
- possible cutting out of parts of the rear apron
- Lay and connect the electrical kit
Which towbar is the right one?
- Pay attention to a trailer hitch with EC type-approval (additional testing and registration by a testing organization can then be omitted)
- choose between a rigid or detachable / swiveling towbar (The latter has the advantage that it has no influence on the overall appearance, but it must be dismantled / folded in when not in use)
What are the differences between the nose weight and the trailer load with the trailer coupling?
- the vertical load indicates how much the coupling can be loaded from above at certain points (usually between 75 and 150 kg)
- the trailer load indicates the maximum total weight of the trailer that is to be towed. (usually between 1.500 and 3.500 kg)

Info: Driving with a trailer causes more wear and tear on the transmission coupling, the brake system and the chassis. (Back to overview)

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