News Article

BPW has launched a new self-steering axle to the UK market for semi-trailers which enables up to 27 degrees of steering angle. This market leading capability will now offer trailer builders and transport operators the option of fitting the BPW self-steer axle on trailers which are 15.6 metre in length, as well as the standard self-steer axle, with up to 20 degrees of steer, for 14.6 metre trailer lengths.

Following the longer trailer consultation results, Keith Marriott from BPW’s UK technical support department, concludes that “in a business where payload capability is key, this exciting new development can give the transport operator the capability of carrying up to 44 tonne GVW, whilst offering considerable cost and weight reductions over traditional command steer options.”

With the BPW modular manufacturing system, this 27 degree self-steer axle can be supplied with either drum or disc brakes, and encompasses the BPW patented load-dependent tracking facility. This unique feature means that it is not necessary to lock the steer axle whilst the vehicle is travelling forward, regardless of speed. The weight of the load acting on the unique pressure bearing keeps the wheels in the straight ahead position until steering scrub is introduced. Equally important, considering the potential difficulties of operating longer trailers when reversing, the self-locking facility automatically locks the steering mechanism in the straight position as soon as the trailer starts to reverse.

1. BPW self-steering axles operate without the need for power assisted stabilisers. They are automatically controlled according to the load being carried. Because the design of the self-steering axle is so simple, thenumber of individual components required is low. This saves weight and reduces installation maintenance costs.







2. The principle of the BPW self-steering axle is described by the abbreviation LL - it stands for load dependent steering. The axle stub is connected to the axle beam via a specially designed pressure bearing. When travelling in a straight line the weight of the load acting on the pressure bearing keeps the wheels in the straight ahead position.











3. When the trailer enters a bend, side forces acting on the tyres cause the wheels to turn slightly and the flanks of the pressure bearing to slide over each other allowing the wheels to move from the straight ahead position and create a steering effect. The degree of steering is dependent on the axle load and the ‘tightness’ of the bend. Both wheels are connected via a tie-bar to ensure the same degree of steer on each wheel.

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