For decades, automatic transmissions had three or four speeds, which were deemed sufficient to provide reasonable acceleration and fuel economy. Then came the five speed automatic, which was standard issue on most cars until just a few years back.
Then, the race for more gears in the transmission began in earnest. First it was the six-speed automatic, followed by the seven speed and eight speed automatic. Embraced by Chrysler
, ZF will now supply eight-speed (and even nine-speed
) transmissions to the automaker for numerous 2013 products.Hyundai
even proclaimed it was developing a 10-speed gearbox in house, which was followed by an announcement from Ford
and GM that they would jointly develop nine and 10-speed gearboxes. The race for transmission superiority, it seemed, would be never ending.
Now, Automotive News Europe
(subscription required) quotes ZF CEO Stefan Sommer as saying nine speeds are the “natural limit.” In Sommer’s words, “There is no hard line, but you have to consider the law of diminishing returns. The question is whether adding even more gears makes sense.”
That sentiment is echoed by Julio Caspari, president of ZF’s North American division, who believes that the race for more gears is driven by marketing and not engineering. As proof, Caspari says that there’s only an 11-percent gap in efficiency between today’s most-efficient gearboxes and a theoretically perfect ideal.
We’d be the first to point out that more gears equal more complexity, higher cost and, potentially, more points of failure. Unless someone can conclusively prove that ten speeds are better than nine, we say let’s turn our attention to other areas, like making more power from less displacement.