What's the efficiency of hub gears compared to derailleurs?

  • What's the efficiency of hub gears compared to derailleurs? I know that hub gears are not as efficient. Apart from being heavier, how much will I lose in performance if I use hub gears?


    Are you looking for numbers or an approximation? If the former, I suggest you mention a particular hub.

    Weight should not affect efficienty, which is a measure of energy input vs. energy output. A bike can be heavy (require more energy to move), and even so be efficient (not wasting energy with friction, flexing, etc.)

    I think he's saying that both lower efficiency and higher weight will "lose in performance", which is true, assuming a route that isn't totally flat and isn't almost all downhill.

  • Ian

    Ian Correct answer

    11 years ago

    A lot depends on the rider and what you mean by efficiency.



    It is easy to keep a hub gear running well for years, but an unmaintained derailleur will become inefficient very quickly. A hub gear allows the chain to be fully enclosed, for all but the most dedicated cyclist; an enclosed chain will be more efficient as it will be cleaner and better oiled.



    An enclose chain allows you to arrive at work, with clean cloths and no need to change, this can save lots of time. Not having to spend time adjusting a derailleur or cleaning your chain also increase the efficiency of your life.
    However it takes longer to remove the wheel if you have hub gears and an enclosed chain.



    Gear shifting efficiency. This is most important in cities with many traffic lights to stop at. With a derailleur, you must shift before you stop, or you'll be starting in a high gear. With an IGH, you can forget about shifting while you are braking, and just select the right gear for the next acceleration a second before you start pedaling. It's a huge difference for a commuter, irrelevant for a racer.



    Personally I think on a road bike:




    • Hub gears are more efficient if you wish to use a bike to make lot of short trips as part of your day to day life.

    • But derailleurs are more efficient if you consider going fast on a bike to be very important and are willing to put the work into the bike that is needed to keep it in a very good state of maintenance.



    (I also like hub brakes for the same reason)


    Rolling up your pant leg also allows you to arrive at work with clean clothes. :)

    @StephenTouset For some reason, I never see people with rolled up pant legs in winter...

    @cmaster You're not looking hard enough.

    "An enclose chain allows you to arrive at work, with clean cloths and no need to change" So does tucking your trouser leg into your socks. Or using trouser clips. Either of those works just fine in winter.

    Third aspect of efficiency: **Gear shifting efficiency**. This is most important in cities with many traffic lights to stop at. With a derailleur, you must shift before you stop, or you'll be starting in a high gear. With an IGH, you can forget about shifting while you are braking, and just select the right gear for the next acceleration a second before you start pedaling. It's a huge difference for a commuter, irrelevant for a racer.

    @cmaster I'd counter that experienced commuter cyclists likely will learn to downshift before stopping. It's one of those fundamental cycling skills. That said, you're correct that hub gears can shift while stationary.

    @WeiwenNg Sometimes, you need to perform an emergency stop. Show me the chain-shifter that manages to do an emergency stop *and* shift down - no problem with an IGH (shift after stop). Also, I'd argue that shifting gears before you stop is as much a bike skill as shifting gears is a car driving skill: The later is almost unheard of in the USA where virtually all cars are automatic, but in other countries where manual gears are abundant, the statement is considered true. Same for bikes: It's only a basic bike skill as long as you equate bike with chain shift. *But IGH bikes are bikes as well*.

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Content dated before 7/24/2021 11:53 AM