The ETI Number Explained: The Key to Finding the Right AL-KO Spare Part

Anyone who has serviced the brakes on their car trailer, replaced wheel bearings or ordered spare parts for an AL-KO axle will come across this term sooner or later: the ETI number. But what exactly does the abbreviation mean, how is the number structured, and why can it save you a great deal of time and hassle when looking for spare parts? Here, you'll find everything you need to know about ETI numbers.

What does ‘ETI’ actually mean?

The abbreviation ETI stands for the German term Ersatzteil-Identifikationsnummer (spare part identification number; occasionally also referred to as Ersatzteil-Identnummer) used by component manufacturer AL-KO.

It serves as a unique identification number for complete axles, wheel brakes or overrun devices. Trailer manufacturers such as STEMA, Böckmann, Saris and Humbaur often use components supplied by manufacturers such as AL-KO, and these components have been produced in countless variations over the years. As a result, the trailer's model designation alone is usually not sufficient to identify the correct spare parts.

The ETI number eliminates the risk of confusion: it tells the dealer or workshop exactly which revision and which components were originally fitted to your axle at the factory.

Where can you find the ETI number?

The ETI number can usually be found on the identification plate of the relevant component – not on the trailer's registration document!

Here is where to look:

1. On the axle: Directly on the axle body (usually around the centre of the axle tube). The plate is generally riveted in place or attached as a durable label.

2. On the wheel brake/backplate: In some cases, the ETI number can be found directly on the brake backplate on the rear of the brake drum.

3. On the overrun device: The towing assembly at the front of the trailer has its own identification plate with a separate ETI number for the coupling components.

How is an ETI number structured?

A traditional AL-KO ETI number consists of 6 digits and, in almost all cases, begins with the digit 8.

• Example format: 811012 or 811.012

The number is sometimes preceded by the abbreviation ‘ETI’ or ‘ETI No.’. In modern systems or catalogues, an additional sequence of digits may occasionally appear before the 6-digit number, but the core identifier remains the 6-digit combination.

What does the number tell you?

Unlike a Vehicle Identification Number (VIN), which encodes information about an individual vehicle, the ETI number is a bill of materials number.

This means that the manufacturer can use the ETI number to identify the exact technical drawing and parts list for the component. If, for example, the manufacturer changes the bearing diameter of a wheel brake by just a few millimetres over the years or uses different brake shoes, the ETI number changes accordingly.

Why is the trailer model designation often not enough?

A common misconception among trailer owners is: ‘I have a 750 kg trailer from Brand X, built in 2015, and I need brake shoes for it.’

The problem is that trailer manufacturers purchase axles and braking systems in batches. Different axle types or different revisions of the same axle may therefore have been fitted within the same model year.

• Without the ETI number: You risk ordering brake shoes of the wrong width, wheel bearings with the wrong internal diameter or incompatible wheel bolts.

• With the ETI number: The number takes you directly to the exploded diagram in the spare parts catalogue that corresponds exactly to your component.

What should you do if the ETI number is illegible or missing?

Particularly on older trailers, or trailers that have been heavily exposed to road salt and dirt, the axle identification plate may become damaged or go missing. If the ETI number is no longer legible, you can take the following steps:

1. Check the backplate: The wheel brake type (e.g. AL-KO 2051) is often stamped directly into the brake backplate.

2. Take measurements: Measure the internal diameter of the brake drum as well as the width of the brake shoes.

3. Take photos: A photo of the dismantled brake will usually help a specialist dealer identify the correct parts quickly.

Conclusion: Find the right part faster with the correct number

The ETI number is the safest and quickest way to find the correct spare part for your trailer axle or braking system. Taking a moment to look underneath the trailer and read the 6-digit number from the identification plate before ordering parts can save you from incorrect orders, returns and unnecessary downtime.

Finding spare parts made easy: Have you found the ETI number for your AL-KO axle and are now looking for the right components? You can use the independent spare parts finder at Trailer.one to search directly by type and specification, helping you get your trailer back on the road quickly.