Trailer Lock: Review & Recommendations

Welcome to our big trailer lock test 2020, where we present you all the trailer locks we have tested in detail. We have put together detailed background information and also added a summary of customer reviews on the web.

We want to make your purchase decision easier and help you to find the best trailer lock for you.

You can also find answers to frequently asked questions in our guide. If available, we also offer you interesting test videos. Furthermore, you will also find some important information on this page that you should pay attention to if you want to buy a trailer lock.

The most important facts in brief

  • Trailer locks are an essential measure against trailer theft and can be found in three different variants.
  • A basic distinction is made between trailer locks with low, medium and high protection against theft.
  • Although there are other ways to protect against theft, trailer locks are the most common way to protect against thieves.

Trailer lock test: Editors’ favourites

  • The customer favourite among the trailer locks
  • The best socket lock

The customer favourite among the trailer locks

The Timtina box lock is an anti-theft device with an average price. The case is made of a galvanized, stable metal and according to the manufacturer is 99% adaptable to all couplings due to the 2 adjustment possibilities. The exact dimensions of the product are approximately 210 mm x 108 mm x 127 mm.

The manufacturer also offers a round lock made of stainless steel with two keys. The lock is extremely popular and is highly praised by many buyers with many reviews because of its stability.

The best socket lock

The socket lock is offered by the manufacturer with two keys. The manufacturer promises compatibility with many products from ALBE, AL-KO and Winterhoff. With its low price the socket lock is also easy to handle.

The weight of the product is a light 25 grams and is therefore easy to stow and store.  According to customer reviews, the socket lock is a worthwhile purchase because of its ease of use.

Guide: Questions you should consider before buying a trailer lock

What is a trailer lock?

A trailer lock is a special lock that typically protects trailers and caravans from being operated by unauthorised persons.

After purchase, vehicle trailers usually have a simple socket lock. This lock is intended to protect the trailer against theft.

It is possible that socket locks can be cracked by amateurs in no time at all. Basically, you can call a trailer lock a reliable anti-theft device.

How does a trailer lock protect against theft?

In principle, the function of all locks can be determined in the same way. The lock has the task of protecting the object from unauthorized persons.
Since a trailer cannot be moved easily due to its size and usually requires a car, a lock is used to break the connection between the trailer and the car.

The point behind the lock is that you cannot connect a vehicle to the trailer without removing the lock in front of it.

An ordinary mortise lock and the integrated lock system of the trailer can be cracked relatively easily and with little experience. This requires simple bolt cutters, which are likely to be used by any trailer thief.
However, there is another function that a trailer lock has to protect against theft. The lock has the property to serve as a deterrent.
Casual thieves therefore prefer to look for simpler items that can be stolen with less effort.

What does a trailer lock cost?

There are relatively large price differences between the various trailer locks. The general differences in price depend mainly on the category of the trailer lock.
This means that the effectiveness of protection against theft plays an important role in the price. For this reason, a certified, high-ranking trailer lock can sometimes be worth 120 euros, although simpler lock variants are available for as little as 5 euros.
However, the price is strongly dependent on the manufacturer and is usually influenced by the manufacturing material. For example, solid case locks with hardened steel are considerably more expensive than simpler locks, but also offer a higher protection factor.

Where can you buy a trailer lock?

You can buy trailer locks easily and conveniently in online shops, but for those who enjoy the personal aspects of shopping, they can also be found in hardware stores, supermarkets or outdoor and camping stores.
Trailer locks with low and medium protection can be found in the above mentioned areas as well as in various online shops.
Certified trailer locks with high protection on the other hand, are normally manufactured by individual dealers, such as ” AL-KO “, and are therefore only available in Germany for interested parties in the online shop or by import.
According to our research, most trailer locks are sold through these online shops:

What alternatives are there to a trailer lock?

Of course there are also alternatives to protect your trailer from theft. These alternatives are also in combination with the trailer lock even more effective in the fight give the stealing of trailers.

In the end it is up to you how and to what extent you want to protect your trailer lock. However, depending on the product, all these alternatives have certain advantages and disadvantages that you should consider.

Nevertheless, trailer locks are the most commonly used means of protection against theft.

Decision: What types of trailer locks are there and which one is right for you?

If you want to buy a trailer lock, you have the choice between three types:

  • Simple trailer locks
  • Trailer locks with medium security
  • Certified trailer locks

The simple trailer locks are socket locks which are usually added after the purchase of a trailer.

To the trailer locks with medium security belong basically the box locks which are a very popular purchase for trailer owners because of a good price-performance ratio.

Certified trailer locks are the last option and are often only produced individually. Depending on how you want to use your trailer lock, a different type is suitable.

In the following section we want to help you with your decision.

What distinguishes a simple mortise lock and what are the advantages and disadvantages?

A simple socket lock, as the name suggests, is pushed (plugged) into a locking channel of the trailer coupling and then locked with an associated key.

The advantage of the socket lock is that it is very easy to use. It is also very easy to store. With the size of a key it is very easy to stow in the glove compartment.


Easy to use
Easy stowage


Easy to crack
Easily visible and therefore no high deterrent effect

What distinguishes a case lock and what are its advantages and disadvantages?

Box locks have a very distinctive appearance. Due to the box-like construction of the lock, they not only protect the entire coupling of the trailer, but also have a high ability to deter thieves.

However, with a length of 23 cm and a width of 12 cm, the steel box is difficult to stow in the vehicle because of its size and can cause inconvenience when driving.


Good price-performance ratio
contactor against damage
High deterrent effect


Difficult to mount

Another disadvantage is that a box lock is difficult to handle. Since the case is relatively solid, the assembly is not always easy. For campers and trailer owners who are in a hurry, this can be fatal.

Advantageous is the stability, the housing consisting of hardened steel. This makes the lock much harder to crack than a simple mortise lock and cannot be removed with a simple hammer, for example.

In addition, the lock protects against slight bending, which could be caused, for example, by a vehicle driving against it.

What distinguishes a certified trailer lock and what are its advantages and disadvantages?

Since certified trailer locks are individually created by certain manufacturers, they usually have different appearances.

However, the quality of the production and the material are excellent for all of them. Whereas simpler locks are usually made of cast iron or brass, the situation is quite different with certified trailer locks.


Mounted while driving
High security
High deterrence


High costs
Hard to find locally (DE)

These are often made of stable and qualitative materials. Individual shapes and components also ensure high security standards for certified trailer locks.

Some products even use eye-catching colors that have the sense to catch thieves’ eyes even more easily. There are also some variants that allow you to leave the lock attached to the clutch while driving.

A disadvantage of the certified trailer locks is that they are not so easy to find in Germany. In most cases this category of locks can only be found in online shops.

Purchase criteria: You can compare and rate trailer locks based on these factors

In the following we will show you on the basis of which aspects you can decide between the multitude of possible trailer locks.

The criteria you can use to compare the anti-theft devices for trailers include

  • Material
  • Size
  • Montage
  • Safety class

In the following paragraphs we will explain what is important for the individual criteria.


This criterion is very important when choosing a trailer lock, as it contributes directly to the safety and protection of the trailer.

In any case, you should be aware that simple mortise locks are usually made of cast iron. Cast iron is relatively unstable and can be easily broken.

So look to find a lock with harder metal such as brass.

It is also very important that you check the keys to the lock before you buy. If they look too small or fragile, you should be aware that these keys can break very easily.

In the worst case you would have to break the lock with tools or a drill.

In the case of box locks, hardened steel is generally traded.  Check with your manufacturer to make sure it is indeed hardened steel and not a fragile substitution.

The quality of the weld seam is very important for box locks.  If you discover any irregularities, it can lead to a very easy breaking of the lock.

The lock is only as strong as the combination of the materials used for it. Watch this video to see if there is a faulty weld:

Since certified trailer locks are only processed with selected high quality materials, you do not need to worry about the material.

Nevertheless the product must be checked for quality. The price should also correspond to the quality.


Since there are different variants of trailer locks, there will be different sizes of locks accordingly.

First of all you should be aware of which variant of the lock suits you best.

Mortise locks generally have a length of 15 cm to 20 cm and a width of about 12 cm. Since most manufacturers install an integrated socket lock in their trailers, the size of the lock is similar everywhere. Check the compatibility with your trailer anyway.

However, the size of box locks can vary depending on the manufacturer.  The length, width and height of the lock are 210 mm, 108 mm and 127 mm respectively.

However, it is very important that you measure the length, width and height of your trailer coupling before you buy and then come to a decision.

In some cases, certified trailer locks are similar to box locks.  However, there are manufacturers who make individual locks. Often the size then matches the individual design of the manufacturer.


Simple mortise locks can be fitted simply by inserting the mortise lock into the enclosed slot in the trailer coupling.

This video shows how this is done:

With box locks, the assembly can be carried out differently depending on the type. However, rim locks are always mounted in a very similar way.

First the box is put over the coupling of the trailer.  Then a security bolt with a so-called discus lock is locked by a slot on the side.

To get a better picture, it is worth watching this video:

Safety class

Basically you can distinguish between three different types of security classes. Trailer locks with:

  • low anti-theft protection
  • medium anti-theft protection
  • high theft protection

Locks with low protection

These locks include simple mortise locks. These locks are usually installed by the trailer manufacturer, but can be retrofitted by the owner if not available.

In addition, the simple socket locks are cheap and easy to use, which can lead to problems.

The problem in this case is that locks of this type are easily cracked by levering them out and therefore offer only low protection against theft.  They are therefore only effective as a deterrent against casual thieves.

Locks with medium protection

So-called box locks are currently the most frequently used trailer lock variant.

With their sturdy, boxy appearance, they not only deter casual thieves, but are much harder to pick than simpler locks.

The material consists of hardened steel and therefore ensures high stability and protection against theft.

Basically, larger tools are required to crack a box lock and therefore cannot simply be broken with a hammer blow or bolt cutter.

Locks with high protection

The most reliable and, given dimensions, most expensive variant are certified trailer locks. However, these are produced and marketed by individual design by correspondingly well-known manufacturers.

Well-known manufacturers in the industry such as “Alko Safety” and “DoubleLock”, ensure the highest security level for trailer locks with high and qualitative materials.

However, you should note that these certified trailer locks are only available in countries where insurance companies require trailer locks of this class.

Since no security criteria for theft protection are defined in Germany, it might be advantageous for interested parties to import.

Trivia: Worth knowing facts about trailer locks

What do I do with the trailer lock while driving?

Storing a trailer lock can often become a problem. But here the size is often the problem.

Whereas simple mortise locks fit effortlessly into a trouser pocket, with box or certified locks it can quickly become fatal to find an ideal place to store them.

Many certified trailer locks have the ability to remain attached to the coupling of the trailer. Often these also provide additional protection for the coupling while driving.

However, box locks do not have this capability and must be dismantled and securely stowed away each time.

How do I recognize a certified trailer lock?

Certified trailer locks are only produced by certain manufacturers. The distinctive quality and the corresponding price often speak for the certification.

In most cases the manufacturer is specialized in the field of anti-theft and trailer protection. It is helpful that you read reviews about the product and pay attention to the word “certified”.