Internal Gearing. Opinions?

Discussion in 'Bike buying advice' started by FlyingPancreas, Sep 1, 2013.

  1. FlyingPancreas

    FlyingPancreas New Member

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    In my bike search, I got pretty interested in the Charge Zester. But the model, which is difficult to find in the US to begin with, has been replaced with the 2014 Grater. The latter, unlike the former, has 8-speed internal gearing (Shimano Alfine 8). Offhand, I guess the whole internal gearing concept seems like a pretty logical evolution from derailleurs. But I am completely unfamiliar with them and how they actually feel and function.

    Anyone familiar with them? What do you think?
     
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  2. vspa

    vspa Active Member

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    german Rohloff system is used by some long touring cyclists, i wouldn't trade it for common derrailleurs though, because of the ease to repair and ubiquitous spare parts,
     
  3. FlyingPancreas

    FlyingPancreas New Member

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    Good point. Thanks.

    Never heard of internal gearing before today, honestly. The few reviews I've found seem very positive, but they are few and there was one mention of a rather extreme PITA when changing/repairing tires.

    As a noob, just looking at standard gears and derailleurs & shifters, it is a complete mystery to me how this stuff actually functions without chains just flying off all the time. Kind of the way I know well how to flick on a light switch or computer, but couldn't explain the guts of their operation to save my life. Bit I find the whole concept of internal shifting pretty interesting as it's the first alternate drive system I've ever seen on bicycles.

    Just to look at the Grater 3, the first thing that struck me was the seemingly small diameter of the crank. Would this translate to slower top speed? Or are internals such a different animal that I shouldn't be conflating diameter with speed?

    http://www.chargebikes.com/bicycle-collection/grater-3
     
  4. alienator

    alienator Well-Known Member

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    You have to think about things a bit differently with internally geared hubs. The hub itself will have a range of gear ratios. Then there will be a gear ratio on the outside of the hub that will be equal to the number of teeth on the chain ring (at the crank) divided by the number of teeth on the external gear (output gear) of the rear hub. Multiple those two gear ratios together, and you'll get the overall gear ratio. The Alfine 8 hub has gear ratios running from 0.527 to 2.153. I don't know the number of teeth on the hub's external gear or on the chain ring for that Charge bike, but it looks to be a bit over 1, so let's say it's 1.25. That'll give an overall gear ratio of 0.659 to 2.691. Now let's compare that to road bike with derailleurs. Common gearing is a pair of chain rings with 50 and 34 teeth, and a cassette that runs from, say, 12-27 teeth. Such a setup would give gear ratios that ranged between 1.21 and 4.16. Keep in mind I guessed at two of the gears on the Charge bike, but you can see that it's likely that the Charge bike has much lower gearing, meaning that it'll have gears that make pedaling uphill easier, but it won't have the top end of a typical derailleur equipped road bike. Such a contrast makes sense as internal geared hubs are quite often used on commuter bikes and/or touring bikes, bikes on which top end isn't key but easier pedaling with loads or uphills is.
     
  5. jpr95

    jpr95 Active Member

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    AASHTA (As Always, Sheldon Has The Answer):

    http://www.sheldonbrown.com/internal-gears.html
     
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