Will Shift Kit work with internal hub transmission?

Discussion in 'General Questions' started by Fletch, Oct 17, 2010.

  1. Fletch

    Fletch Member

    I have a bike with an internal hub 3 speed transmission and I'm curious if it would work with the SBP shift kit? Can it handle that much torque from an engine? Would it be worth it with only 3 speeds?

  2. MotoMagz

    MotoMagz Member

    I know people use the internal hubs.As for how they hold up I would not know.But as for only having 3 gears that would be fine.It is really about the range between the gears.I have a 7 speed and only use 3 of the gears most of the time.I go first to third to sixth.& seventh is my freeway gear and I don't go there often!
  3. RedBaronX

    RedBaronX Member

    just a few days ago, I asked SBP if there was any internal hub that they recommended besides the very expensive NuVinci, and their response was that they receive so many mixed reviews regarding LOTS of different internal hubs that the only one that they can confidently recommend is the Nuvinci shift hub (which is around $500).

    WILL it work with yours? The SBP's shift kit works with any shifting system-- the point of the kit is that the motor drives the back wheel with the pedal chain while allowing the rider to switch between motor and pedals at will... which means you could even use the shift kit with a single speed hub if for some reason you wanted to...

    So, will yours work at all? Yup. Is a three-speed transmission enough gears to make shifting worthwhile? I personally think so and plan to do so when I build my next bike. But is your internal hub good enough? THAT is hard to say... I personally would only trust the quality of one that was brand name, pretty new, rated to be rugged, blah blah blah... Maybe yours is all that... if you don't know, you can find internal shifting hubs that are half or less the cost of the NuVinci hub.
  4. 5-7HEAVEN

    5-7HEAVEN Guest

    $299 NuVinci hub::tt1:


    Other options




    Most of my issues on my MB are chain jumping and breakage, gear-jumping. Thinking about 8-speed running internal hub. The NV's price dropped at Staton's, which makes it comparable in cost to multi-speed internal hubs.
    Last edited by a moderator: Oct 17, 2010
  5. professor

    professor Active Member

    One comment to 5-7, what if you take out links from your drive chain, thus putting more tension on the chain?

    Also- For a few hundred miles so far- I am using a 3 speed hub as a jackshaft after a HF79.
    Having gears is great. There is one problem with using this hub- it drops in and out of third gear at anything over a slow cruise, this is annoying. I tried making a reverse shift set-up so the little pull cable holds it in 3rd- still drops out.
    I don't know how much power or abuse these Sturmy Archer old hubs can take. The response to other posts about the hubs is "not much".
  6. 5-7HEAVEN

    5-7HEAVEN Guest

  7. save your money & buy a friction drive kit. then you shift all you want
  8. RedBaronX

    RedBaronX Member

    "save your money"? a friction drive motor and kit is more expensive than a SBP shift kit and a nice internal shift hub combined... shift kit is $200, a quick Google search of friction drive engines and kits show them being $400 and up... (I stalked the profile of the OP to see that he already has an HT installed; he's not starting from scratch...)

    and if the 3 speed hub he has isn't durable enough for the chain-drive shift kit, it won't be durable enough to shift with a friction kit either. The exact stress might not be the same since the stress from the drive chain of the shift kit is "concentrated" on the shifting hub while the stress of turning the wheel with a friction-drive is spread out over the whole wheel, but the potential speeds are the same, and you still have the stress of the engine vibration...
  9. 5-7HEAVEN

    5-7HEAVEN Guest

    Welcome to the forum.:cool:

    LOL, been there, done that, many many times.:jester:

    FACT: Friction drive is NOT the best drive system for a high-winding engine with a very narrow powerband.:detective:

    FACT: If you can harness a high-winding engine with a narrow powerband, you will have an AWESOME MB.:bowdown:

    How do you shift with a friction drive kit?
  10. shifting FD

  11. 5-7HEAVEN

    5-7HEAVEN Guest

    Sorry Mikey, that's not what we mean.:cool:

    We want the engine directly connected to the multi-speed cassette or internal hub, so pedals and engine goes thru the same single bike chain.:detective:
  12. professor

    professor Active Member

    5-7, how about replacing the bike chain with just a heavier chain if you do a Nuvinci? That way you get to keep the stock sprockets.
    I ordered some heavier 1/2 inch chain for my moped from McMaster Carr. It fits on bike sprockets- has some slop sideways but sure won't break!
  13. 5-7HEAVEN

    5-7HEAVEN Guest

    Professor, that's what I'm gonna do, sorta. Changing to 8mm chain and sprockets. Pocketbike freewheel mechanism threads directly onto NuVinci hub, then any 4-bolt T8F sprocket bolts on. 8mm chainring sprocket also bolts up at the bottom bracket. I already have a 72t 8mm sprocket and just ordered 8mm chain and 36t sprocket for the rear NV hub.

    Right now I have 8mm engine sprocket and chainring. So I'll have 8mm drivetrain throughout. Chains and sprockets should be strong enough, since they're made for pocketbike engine power.:detective:
  14. 5-7HEAVEN

    5-7HEAVEN Guest

    Another reason I'm switching to internal hub is because the chain will not move laterally(side-to-side)throughout its operation. Whenever I watch the bike chain move thru its 8 gearshifts, I wonder:

    HTF does it stay on its sprockets?

    With no lateral movement, this should cure my chain problems.

    I am SO TIRED of stopping and resetting the chain on every ride. Sure maybe it's my not having the chainline dead-on.

    I wish my bike would give me a break.

    I think that my bike is trying to kill me.:whistling:
  15. Fletch

    Fletch Member

  16. Beau

    Beau New Member

    The NuVinci hubs are a joke. You can't shift them under load unless you REALLY twist the grip shift hard. They are really not that great.

    This bike has a Shimano Nexus 3 speed and works great. The parts are easy to find, they are tough and they perform better that Sturmey's.


    He made a jack shaft that mounts behind the seat tube. It's very fast and works great.
  17. SimpleSimon

    SimpleSimon Active Member

    Thing is, shifting the multi-speed options (dérailleur or internal geared hub) does absolutely NOTHING as far as a friction drive is concerned. A friction drive has only one ratio - drive spindle/outer tire circumference. That's all it can provide, except for slippage. Like a child's tricycle, an FD system is direct drive - no effective gear choices.

    Now, it is quite possible to build an FD system that would be capable of at least two, and possibly more speed ratios, and "shift in motion". It isn't even all that complicated to do.

    As far as the durability of most internally geared hubs goes, think about what they are designed to do. To wit: stand up under the torque load of an adult human being standing on the pedals, pulling on the handlebars and bearing down - a much greater amount of torque than most any small engine will ever produce.

    The biggest problem is transmitted vibration and the design of all but the NuVinci hub - they all use internal cogs. The greater the number of gears provided, the thinner those internal cogs tend to be in construction, and the more susceptible they become to vibratory failure.

    So, using good motor mounts that lessen vibration transmission, and the SBP jackshaft system (which further isolates engine vibration from the rear hub just by its design) should not cause undue problems.
    Last edited by a moderator: Dec 18, 2015
  18. 5-7HEAVEN

    5-7HEAVEN Guest

  19. SimpleSimon

    SimpleSimon Active Member

  20. 5-7HEAVEN

    5-7HEAVEN Guest

    Might not be complicated to you, but it is to me. Also not worth my time since progressing from friction drive to shift kit.

    It'd be nice to see you fab this up, though.