Hyundai to Build 10-Speed Transmission, But Why?

2011 Hyundai Equus

I’m guessing plenty of CarGurus readers know much more about semi trucks than I do, but when I read that Hyundai plans to release a 10-speed transmission for its luxury cars in 2014, I wondered how that compared with the number of gears in the big rigs.

Some quick research told me that, in fact, the most common number of gears in an 18-wheeler is 10.

Do our luxury cars really need the same number of gears as semi trucks?

I don’t think so. But, with Lexus and others using 8-speed trannies, it only makes sense that an automaker wants to one-up (or, in this case, two-up) them. Ford and Chevy engage in fierce horsepower wars, and now it looks like the transmission wars are upon us. How incredibly…dorky.

10-speed transmission shifter map

A proper 10-speed

Granted, semi trucks use manual double-clutch gearboxes, while the 8- and 10-speed boxes used in cars are of the automatic variety. Still, though, it seems like tranny overkill. Will a tenth speed really offer better fuel economy at 70 mph than an eighth speed? How fast would a car have to go before a shift down into tenth would be needed? I mean, seriously, the Bugatti Veyron, the fastest car in the world, does just fine with a 7-speed box.

Hyundai might be better off fine-tuning its existing transmissions to shift more precisely before upping the number of gears it uses. Or, at this point, why not just go the CVT route and have an “infinite” number of gears available?

If there’s an engineer out there (I know we have a few!) who might be able to explain how a 10-speed would be any more efficient than a 6-, 7- or 8-speed, I’d be curious to hear your thoughts. Otherwise I think announcing a 10-speed is mostly for show and a way to out-market the competition.

It’s no secret that Hyundai wants to out-Lexus Lexus, and one way to do that is by offering a “bigger and better” transmission than the Japanese automaker.

I happen to believe that bicycles and semi trucks should be the only things with 10 speeds or more. Do you?

-tgriffith

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3 Comments

  1. Well, we know these omni-band transmissions are viable because many are already on the road. I think in the case of these transmissions, the primary goal is actually driveline feel and the secondary benefit (although still a big one) is greater operating efficiency. As the CAFE standards become more stringent, car makers will need that extra 10% from the driveline. Remember, too, these newer transmissions have multiple clutches and it’s also possible to eliminate the torque converter, which also yields more economy. I amazed they are so reliable but the ability to cheaply machine parts to very high tolerances makes that possible. In the old days, an automatic transmission had to handle around 350 lb.ft. of torque and push a 5000 pound car with only two or three ratios, which required a lot more beef. Modern lighter cars with smaller engines and computer controls can get away with much lighter drive trains, so the more complex transmission aren’t necessarily a lot heavier.

  2. I am not an engineer. But I would assume there is a point of diminishing return on a transmission size. When does the added weight and cost limit the performance of extra gears? Maybe it’s 6. Maybe it’s 12. I would think we’re getting close with a 10-speed…
    Randy, do you think it’s viable?

  3. One advantage of more speeds is that you can keep the engine RPMS in the most efficient part of the engine efficiency curve. You also, of course, get much smoother shifting because of the smaller RPM change and closer next gear ratio. In some ways, you’ll start to get the feel of a CVT without the friction and torque limits of that design. As with all engineering compromises, though, you get more complexity, higher cost, and reduced reliability.

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