BMW Says No Dual-Clutch, Opts for Eight-Speed Automatic

ZF eight-speed automatic tranny

BMW will rely more on eight-speed automatic transmissions and less on dual-clutch systems, Klaus Draeger, BMW’s development chief said today, pointing to a number of advantages brought by an automatic unit. First of all, the dual-clutch transmissions are far more complex than the automatic version plus they are more expensive and heavier, which obviously reduce the overall engine performance and force the manufacturer to use lightweight materials for a number of different parts.

At this time, BMW is already offering dual clutch transmissions in 3 Series coupes and Z4 Roadster but, due to the fact that using them on cars with longitudinally-mounted engines and rear-wheel drive systems makes the assembling process a bit more complicated and expensive, the company aims rely more on eight-speed automatic units.

In fact, eight-speed transmission systems are already being produced by ZF Friedrichshafen who design such units for cars featuring rear and all-wheel drive systems. According to Autonews, the first BMW and Audi models incorporating an eight-speed tranny are expected to arrive later this year.

“The eight-speed automatic that we developed with ZF can compete with dual-clutch transmissions on shifting times, but it’s lighter and more efficient and has cost advantages. The incompatibility with high engine-speed designs is a disadvantage, however,” Klaus Draeger said.

While BMW abandons dual-clutch systems, American automaker Ford sees this kind of unit as the perfect way to reduce fuel consumption so it recently announced that several North American models will get this option starting 2010.

"PowerShift represents a true competitive advantage for Ford and is one of the many technologies that will help our global small-car platforms set a new world standard for efficiency and drive quality," said Barb Samardzich, vice president, Global Powertrain Engineering, who announced PowerShift's production timing at the 2009 Automotive News World Congress. "This advanced six-speed is an improvement over today's automatic transmissions in terms of fuel economy, while providing customers an even more fun-to-drive experience.”