How Many Gears Is Too Many

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Comments (13)
Repost
Bumps(30)

Toyota Direct-Shift Gearbox

There are very legitimate reasons why we're seeing 10-speed automatic transmissions implemented in new cars, such as the Lexus LC500. More gears means a broader range of gear ratios without massive steps between those gear ratios. It means you can keep your car's engine closer to peak horsepower in order to achieve maximum acceleration, and it means you can put your engine in the right load and RPM range in order to maximize efficiency.

This video will dive into the details of why more gears can be a good thing, even with the negative consequences such as additional complexity, frequent gear shifts, and time lost in acceleration from more frequent shifts. The Lexus LC500 pairs a 5.0 naturally aspirated V8 to a 10-speed automatic transmission, and it sounds quick beautiful churning through the gears. That's not to say the transmission isn't without flaws. Check out the video for full thoughts on 10-speed transmissions and the implementation within the LC500.

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Comments (13)
  • Dynaflow is the trade name for a type of two-speed automatic transmission that was built for Buick from 1947 to 1963. The Dynaflow set itself apart from its competition with its ability to shift smoothly from one speed to the next. This was a vast improvement over most automatic gearboxes of the time, which tended to lurch their way through gear settings. It was also a vindication of torque converter-equipped transmissions, setting the standard for their use up to the present day.-Posted by ETE Product Support on Wednesday, March 12th, 2014 .

    1 month ago
  • Holden 2 speed Auto - the " Powerglide " 1950s to early 70s - a 1178 kg, 108 or 145 BHP 1967 Aussie HR Holden could get about 30 mpg around town with this gearbox . Very calmly.

    1 month ago
  • " Above a certain level, complexity is fraud " - P.J. O'Rourke.

    1 month ago
  • The question raises a lot of other questions because it's not limited to automatics. If a 10 speed automatic is "optimal", why not a 10 speed manual? Yes, that's absurd for a car.

    A hydraulic or CVT automatic may be less efficient than a manual or dual clutch but the rest of the powertrain programming and design can be made to compensate.

    I just bought my first CVT transmission car. Given a choice, I prefer a manual every time, but I decided to give it a go. I've owned cars with hydraulic automatics and driven dual clutches. They have their pluses, but they're not my first choice. I'm surprised how good the CVT in my car is. Granted, we're not talking a performance car, but a daily driver.

    CVT's are the big variable (pun intended) and every generation improves on the last. It's far more complicated than belt or toroidal. It's the range of ratios and programming. In theory, a CVT can have more than the current equivalent of the range of 10 ratios "traditional" automatics. That doesn't include the in-between ratios.

    We've all been in cars with automatics that "hunt". (Right. 4th Gear. No 3rd Gear and more revs. Oops, 4th was better. Oh, wait, there was a gust of wind, back to 3rd. Damn, now we're going downhill, back to 4th.) It's subtle but annoying.

    Like I said, I prefer a manual and the CVT is my current car works well. But a 10 speed automatic? That's a bit much.

    1 month ago
    2 Bumps
  • They only do it to improve fuel emisions

    Drag cars accelerate really fast with 1 or 2 gears

    3 months ago
    1 Bump
    • Very true but you can't really compare them.

      For example, drag cars can't really cruise at 10 or 120, and they need to be rebuilt every run.

      3 months ago
      1 Bump

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