BPW Brakes – How the Brake System on Your Trailer Works

BPW under your trailer? Then you are running a brake system with over a hundred years of German engineering behind it. Here we explain how BPW’s brake technology is built, which parts are included, and what to look out for when it is time for maintenance. We have the spare parts ready.

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Who Are BPW?

BPW, or Bergische Patenten Wagenfabrik, was founded in 1898 in Wiehl, Germany. The company started with axles for horse-drawn carriages and has since grown into one of Europe’s leading manufacturers of axle and brake systems for trailers. BPW is particularly strong in the segment for heavier trailers and boat trailers, but also supplies systems for lighter trailers. Brands such as Harbeck, Pega, and several other European manufacturers rely on BPW’s technology.

How a BPW Wheel Brake Works

BPW’s trailer brake system is based on the same proven principle as other mechanical drum brakes: an overrun device via the ball coupling, brake cables that transfer the force, and brake shoes that press against the inside of a brake drum. What sets BPW apart is their focus on precision and durability. The components are designed to handle heavy loads and often demanding environments, such as salt water in the case of boat trailers.

BPW offers systems with both manual adjustment and automatic self-adjustment. Automatic self-adjustment means the brake compensates for wear on its own, providing more consistent braking performance over time and reducing the need for manual servicing.

The Components of a BPW Brake System

A BPW brake system is made up of several interacting components. Here are the most important parts and what they do:

Brake shoes and linings – The friction material that presses against the brake drum. BPW brake shoes are available in dimensions such as 200×50, 230×60, and 250×40. The linings wear fastest and should be inspected regularly.
Brake drums – The rotating surface the brake shoes work against. BPW drums are designed to withstand high loads, but still wear over time and may need replacing if braking becomes uneven.
Brake cables – The link between the overrun device and the wheel brake. BPW cables come in different lengths and configurations. A cable that starts to corrode or stretch should be replaced before braking performance is affected.
Wheel bearings – BPW uses compact bearings and tapered roller bearings depending on the axle series. The bearings are subjected to significant forces, especially on boat trailers where salt water and repeated launching take an extra toll.
Spring kits and adjustment mechanisms – Return springs, pins, and self-adjuster components that keep the brake correctly set. These small components are critical for the entire system to work as intended.
Backplate (mounting plate) – The fixed plate on which the brake mechanism is mounted. This is often where you find the brake ID or axle series number that identifies your specific configuration.

BPW and Boat Trailers

BPW has a particularly strong position in the boat trailer segment. Their axle and brake systems are popular among manufacturers building trailers for launching, where components are exposed to salt water, sand, and repeated loading. This also means wear can occur faster than on regular road trailers. If you have a boat trailer with BPW brakes it is especially important to rinse the brakes and bearings with fresh water after each launch, and to check the condition of the brake components regularly.

Signs That the Brakes Need Attention

Trailer brakes do not always give clear warning signals, but these signs should prompt you to act:

Uneven braking – If the trailer pulls to one side, the brake shoes or cables may be unevenly worn.
Weaker braking performance – Gradual deterioration is often caused by worn linings or cables that have lost tension.
Scraping noise while driving – Can indicate that the linings are worn out or that the drum has been damaged.
Wheels are difficult to turn by hand – Suggests the brakes are dragging, often caused by tired springs or a seized cable.
Heat from the wheel hub – Unusual heat after a short journey can indicate a problem with the bearings or a brake that is not releasing.

Common Brake Models from BPW

BPW’s range includes several brake models. The most common ones found on Nordic trailers are:

BPW S 2005-7 RASK
BPW S 2005-5
BPW S 2035-7 RASK
BPW S 2304-7 RASK
BPW S 1704-7 RASK

Not sure which model you have? Check the serial number on the axle tube or the brake ID on the backplate. You can also use our registration number search at the top of the page.

Valeryd Has the Spare Parts You Need

We stock a wide range of spare parts for BPW brake systems. Brake shoes, cables, drums, bearings, and accessories are all available and can be ordered directly on our website. Enter your registration number in the search box above and you will immediately see which parts fit your trailer or boat trailer.