Internal Gear Hubs as transmission?

Discussion in 'General Questions' started by DougC, Sep 23, 2009.

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  1. DougC

    DougC Guest

    I know this has been asked in the past but haven't been around for a while and want to know if anyone has tried doing it since.

    I know it has been found that a Shimano internal-gear hub (used as the rear-wheel hub) will not withstand very much torque for very long driven straight off an engine, such as what motorized use gives it. What I am pondering is if anyone has attempted to use an internal-gear hub as a sort-of "jack shaft", in a GEBE-style system.

    In the GEBE bikes, the engine has a toothed pulley about 1 inch across, and a belt that goes to the rear wheel sheave, that is about 16 inches across. Like many bike motor kits, it has a major problem with climbing hills, especially when starting.

    If you took a 3-speed or 7-speed Shimano internal-gear hub (IGH) and geared it 1:1 with the engine's output, and then geared the IGH's output roughly 1:16 to the rear wheel however you had to, then the IGH is going to spin a lot of RPMs but it will not be under very much torque at all. From all I've read, it's high-torque use that kills IGH's more than anything.

    The Nexus-7 has a 244% range (top to bottom) so it should be able to handle hills much better, yet still may add some speed on the top end.



  2. GearNut

    GearNut Active Member

    I don't know how well the internals would stand up to high speed use.
    Pedaling under human power is not that fast, and that is what these hubs were designed to handle.
    I don't know, but I wonder?
    Right now I have a question posted concerning the differences between 2 kits. Hill climbing power is important to me.
    I really like the GEBE kit due to their simplicity. I now have one count of GEBE's do not like hills. Thankyou!
  3. Fabian

    Fabian Well-Known Member

    Maybe this can be of help

    Shimano now has a new cassette available - HG61bh which has a 36 tooth cassette sprocket.
    Some bike shops will tell you it does not exist and they will be adamant it does not exist as i've been through this most frustrating and infuriating process with shop staff when trying to order the cassette.
    Let me tell you though, the 12-36T DOES EXIST and you can purchase the optional 11 tooth lockring to make an 11-36T in a 9 speed cassette.

    Now this company makes some serious specialist hill climbing cassettes and also sells the individual sprockets to make your own custom ratio cassette.
    Scroll down to "titanium Cogsets - does an 11-39T (yes a 39 tooth cassette sprocket) take your fancy and they say (i've emailed actiontec) that the 39 tooth sprocket will work using a standard long cage Shimano Deore rear derailleur.

    Hope it's of help

  4. DougC

    DougC Guest

    You seem to be talking about external-gear hubs (the ones with a number of exposed sprockets, and the chain flips back and forth between them). They're not as useful here because they have to be rolling in order to change gears.

    The Nexus hubs can switch gears standing still, which (in order to start UP a hill) is what you'd need to have.


    Last I heard, the only kit that seems to do well climbing hills is the NuVinci hub.
  5. Fabian

    Fabian Well-Known Member

    Hi DougC

    I agree with your comment and i did understand that you were talking about internal geared hubs.
    Maybe i was wrong, but i got the impression you wanted a very low first gear, a climbing gear or crawler gear for standing starts up a steep hill.

    I just gave an alternative method of solving a very low crawler gearing issue, that doesn't require the extra gear reduction of a geared hub.
    A simple external sprocket is far more simple and achieves the same result as a super low first gear using an internal geared hub.

    From my experience, every time you add complexity into the system, you add unreliability into the system.
    Personally, the internal geared hub system really appeals to me, as it doesn't have all the filthy grease and mess associated with a chain and sprocket drive system.
    Only one thing keeps me away from an internal hub - "what if something goes wrong 50 kilometers from home" - you are completely stuck, can't even pedal the bike home as the hub may have totally locked up of fails to transfer any drive at all.

    At the worst case with a chain and sprocket system, you can pull out your chain breaker and bypass the rear derailleur and run the bike as a single speed unit till you get home for major repairs.
    That's the only reason why i run a chain and sprocket system, because all the working parts are on the outside.

    In no way am i saying an internal geared hub is inferior - if i could buy an ultra heavy duty hub specifically designed to be used with a Chinese motorised kit and heavy loads, it would be on my bike tomorrow.

  6. give me vtec

    give me vtec Active Member

    if you are thinking about an internally geared hub the nuvinci is the only way to go. A little pricey but you definitely get what you pay for. Its pretty much indestructible up to 7hp. I have one on my felt... amazing piece of technology.
  7. Fabian

    Fabian Well-Known Member

    """"rated to 7hp"""" that incorporates a power saftey margin that gets my attention.

    Going straight to google to check it out.
  8. give me vtec

    give me vtec Active Member

    I would go to their site and read the instruction manual... I believe there is a .pdf you can download. There is also a .pdf of all the research, and results of their testing. There are quite a few people here that can vouch for this thing including me.

    Here decide for yourself... I think you will be amazed at this thing. And the best part is its maintenance free.
  9. Fabian

    Fabian Well-Known Member

    It's got me sold: The NuVinci CVP hub has an industry-leading six-year limited warranty

    Thanks so very much 'give me vtec' for informing me of this product.
    With the Nuvinci hub (if it's as good as the manufacturer suggests), all other internally geared hubs have become obsolete (like a 386 computer) and a complete waste of time; even giving any thought thinking about them.

    Thanks again give me vtec for posting that information.
    Can you please put up hi-res photos of the hub installed in your bike.

    Cheers Fabian
  10. loquin

    loquin Active Member

    BTW - Staton sells the Nuvinci kit.
  11. Fabian

    Fabian Well-Known Member

    As the Nuvinci Hub has a 350% drive range, it coulld be paired with the Schlumpf High Speed Drive

    to give a much better range of hill climbing gears (you couldn't really call it gears though) or ratios.

    The thought of getting rid of my rear derailleur is a very inviting option.
    Rear derailleurs were designed to be nothing but trouble.

    A Nuvinci Hub rated to take 7hp and a Schlumpf High Speed Drive would be heaven on a motorised bicycle, especially with a fully loaded trailer with a gross weight of 60 kilos.

    ps thanks for the link loquin - checking it out now.
  12. GearNut

    GearNut Active Member

    I have my 386 computer humming along right next to me and it works quite well. I never have to worry about viruses. My Windows 95 is pretty much immune. :D
  13. give me vtec

    give me vtec Active Member

    You're welcome, I loved the hub and I thought it would suit your needs. You don't need any other gearing, it goes low enough to climb up anything at almost idle. I tested it myself at the beach on some very challenging hills...

    Here is a link... these pictures are kinda old. I hadn't put the shift cables on yet for the hub and I have since replaced that gas tank with a new under-rack style, I also put the rear fender back on. I can post more pics tomorrow if you would like.
    Last edited: Sep 24, 2009
  14. Email

    Email Member

    Internally geared hub with external freewheel.

    I know I need to do some digging to see if the Nuvinci is capable to mix it's internal gearing with an external freewheel (external geared cassette).

    Just bought a Vision recumbent with an internally geared 3 speed rear hub with 7 speed external sproket. The advantage of the internal gearing is it lets you stop at a light while in the high gear, click down to low (without moving), and work back up to the higher gear. The Nuvinci would be great for this as well, if it works in a similar fashion.

    Unfortunately the recumbent's highest gear is not as fast as it needs to be (spins a fast cadence, and I guess it's the lower drag that makes it feel like it's not hard to pedal). I'm debating on putting a triple on the front crank and manually switching it over as desired.

    Yes it's a non-motored bicycle, but still the idea has merit for the motoredbike usage.
  15. camlifter

    camlifter New Member