Knott Brakes – How the Brake System on Your Trailer Works

Does your trailer have Knott brakes? Then you are in good company. Knott is one of the most common brake manufacturers in Europe, and their systems are found on everything from light trailers to heavy boat trailers. Here we explain how the Knott brake works, what can wear out, and how to easily find the right spare parts.

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Who Are Knott?

Knott was founded in 1923 in Germany and has since specialised in brake and axle technology for trailers. What sets Knott apart is their robust and compact designs, which handle tough conditions with minimal maintenance. In the Nordic region you will find Knott brakes on brands such as Respo, Böckmann, Tiki, and several others. There is a good chance your trailer or boat trailer has Knott underneath without you even knowing it.

How a Knott Wheel Brake Works

Like most trailer brake systems, Knott uses mechanical drum brakes activated via an overrun brake. The principle is simple: when the car brakes, the trailer pushes forward against the towing vehicle. This movement is captured by the overrun device in the ball coupling, which activates the wheel brakes via cables. Inside the brake, the brake shoes are pressed outward against the inside of the drum, and the friction slows the wheel.

Knott also offers models with an auto-reverse function, which automatically adjusts the brake shoes as they wear. This means braking performance remains more consistent over time and reduces the need for manual adjustment.

The Components of a Knott Brake System

A Knott brake system consists of several parts that all need to work together. Here is an overview of the most important components:

Brake shoes and linings – The friction part that presses against the drum. Knott brake shoes are available in several dimensions, such as 200×50, 250×40, and 200×35. The linings wear gradually and are the most frequently replaced part.
Brake drums – The surface the brake shoes work against. Knott drums are available in different bolt patterns (4- and 5-bolt), and the correct variant depends on your axle model.
Brake cables – Transfer the force from the overrun device to the wheel brake. Cables come in different lengths and with different end fittings. A stretched or rusty cable is immediately noticeable in braking performance.
Wheel bearings – Knott uses both tapered roller bearings and compact bearings depending on the axle series. Worn bearings produce noise, heat, and play, and should be replaced before they cause more serious damage.
Spring kits – The return springs ensure the brake shoes release from the drum when you are not braking. Weak springs cause the brakes to drag, which increases wear and reduces fuel efficiency.
Backplate (mounting plate) – The base on which the entire brake mechanism is mounted. The backplate carries the brake ID that identifies exactly which brake model your trailer has.

How Do You Know the Brakes Need Servicing?

Trailer brakes wear slowly and it is easy to miss when something is starting to give way. Watch out for these signs:

The trailer pulls to one side when braking – This often means the brake shoes or cable on one side are more worn than the other.
You notice the stopping distance has increased – Worn linings or stretched cables cause braking performance to gradually weaken.
Metallic scraping noise – If you hear metal on metal, the linings have likely worn down completely and the drum is at risk of damage.
Wheels turn sluggishly – If the trailer rolls heavily when unloaded, the springs may be tired or the cables may be seized.
Uneven tyre wear – Can be a sign that the bearings need replacing or that the brake is binding on one wheel.

Common Brake Models from Knott

Knott has a large range of brake models. The most common ones found in Nordic trailers are:

Knott 20-2425/1
Knott 16-1365
Knott 25-2025
Knott KF13-C
Knott KF27-A1

Can’t find your model? Check the brake ID on the backplate, or enter your registration number in the search box above and we will help you match the right parts.

Valeryd Has the Spare Parts You Need

We stock a comprehensive range of spare parts for Knott brake systems. Whether you need new brake shoes, a complete cable kit, or new bearings, you can find them and order directly on our website. Enter your registration number above to get an overview of which parts fit your specific trailer.