The auto industry's race to add gears to automatic transmissions is running out of steam, says a senior executive at Germany's ZF Friedrichshafen AG.
After ZF introduced its eight- and nine-speed transmissions, a press report said that Hyundai was developing a 10-speed gearbox.
Julio Caspari, president of ZF's North American operations, says that additional gears may fail to improve fuel efficiency enough to justify the cost.
Although he did not name names, Caspari hinted that a "Can you top this?" race to add gears may be driven by marketing considerations rather than fuel economy.
That's because there is only an 11 percent gap between the most efficient transmissions today and a theoretically perfect gearbox, he says.
"We are coming close to the limit," Caspari said in an interview with Automotive News, a sister publication of Automotive News Europe. "Can we produce a perfect transmission, and what would it cost? We would need to look at things like ceramic ball bearings to reduce friction, which would be expensive."
In 2009, ZF began producing its eight-speed transmission, which is designed for cars and light trucks with longitudinal engines. The eight-speed delivers 11 percent better fuel economy than a standard six-speed automatic, he said.
Chrysler Group made waves when it adopted the eight-speed transmission for the Chrysler 300 and Dodge Charger.
Next year, ZF will begin assembling its nine-speed gearbox in a plant near Greenville, South Carolina, while Chrysler will produce both the eight- and nine-speed gearbox under license at its plant in Kokomo, Indiana.
ZF says the nine-speed transmission, which is designed for transverse-mounted engines, is up to 16 percent more efficient than a six-speed automatic.
Chrysler says it will use this transmission on all of its front-wheel-drive models.
Which brings us to the hypothetical 10-speed transmission.
Caspari isn't saying whether the company is actively designing a 10-speed. ZF's next project is an upgrade of its eight-speed automatic transmission, Caspari said. And he did not seem overly perturbed that a competitor might roll out a 10-speed automatic first.
Bloomberg News reported in September that Hyundai is developing a 10-speed transmission for its luxury models starting in 2014. The Genesis and Equus sedans were reported to be likely recipients.
For his part, Caspari will believe it when he sees it. "It might never come, or a competitor might introduce it for marketing reasons," he said. "Would a 10-speed be an improvement in the real world? We shall see."