World's First Plastic Rear Axle Transmission Crossbeam

Jointly developed by ContiTech Vibration Control, Auburn Hills, Mich. and BASF, Florham Park, N.J. for the S-Class from Mercedes –Benz is reportedly the world’s first plastic transmission crossbeam in the rear axle subframe of the vehicle.

This component is made of one of BASF’s new “crash grades”, Ultramid A3WG10 CR (crash-resistant), a 50% glass fiber reinforced specialty nylon 66.  Compared to the die-cast aluminum beam it replaced, this highly durable component offers a weight savings of 25%, better acoustics, as well as excellent mechanical properties even at high temperatures and conforms to the latest crash requirements.  The material shows optimum strength and rigidity and displays a low tendency to creep under constant loading. Also, it withstands high-bending torques. The component shows good NVH (noise, vibration, harshness) performance. The design expertise of BASF’s simulation tool Ultrasim is credited for making a major contribution to these properties.

This plastic load-bearing structural component meets all the requirements for the static and dynamic loads which act on a transmission beam: As a central component of the rear axle it supports part of the torque which is transferred from the engine to the transmission, and bears a constant share of the load of the differential. This is why the Ultramid crossbeam is used in all the vehicle designs from Mercedes-Benz with all-wheel drive, with the exception of the AMG cars. 

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