SCHWEINFURT – Whoever aims to be successful in the Rally Dakar requires extremely durable technology. ZF provides highly resilient telescopic shock absorbers for the suspension on rally prototypes.
Jumps over dune crests, rough scree sections and high-speed stages over sand and gravel: probably no other motorsport discipline demands so much of the suspension like cross country rallying with the Rally Dakar as the most famous event.
Teams equipped with ZF technology have taken overall victories in the Rally Dakar in the past – such as the Volkswagen factory team between 2009 and 2011. The latest product on offer from ZF for its cross country rallying customers is a telescopic mono-tube damper with external reservoir.
To cope with the demands made of the suspension, the teams rely on long spring travel. The current top prototypes for instance have suspension that permits a vertical displacement range of 450 millimetres and more. The installation ratio of the damper allows a piston stroke of approximately 200 millimetres. A vehicle weight of around 1.3 tonnes, several hundred litres of fuel as well as driver and co-driver on board mean high dynamic loads – such as jumping over obstacles. Compression speeds of 4 metres per second are common-place.
The ZF shock absorbers are one-way adjustable in rebound. The bump damping is two-way adjustable – for low spring speeds of up to around 500 millimeter per second as well as for the range above.
In addition to the mechanical demands made of the components, intensive thermal loads also occur in cross country rallying. For many years now, it is normal for the leading teams to counter the permanently high loads in the cars by using two dampers per wheel. Rally stages often run for several hundred kilometres each day through rough terrain. The damper must therefore deliver top performance for hours on end. ZF designed its components to operate in temperatures of 150 degrees Celsius, but higher peak loads do not overtax the dampers. Seals and oil are developed for such temperatures, the reservoirs are ribbed to help heat dissipation, and active airflow in the vehicle often further optimises the thermal management.
ZF operates in this way as efficient and capable partner in one of the most demanding motorsport disciplines on earth. Victory in a desert rally over 5,000 kilometres in Asia during the 2015 season underlined the qualities of the damper from Schweinfurt.