Multi speed DAX Titan?

Discussion in 'Rack Mounted Engines' started by duivendyk, Jul 12, 2008.

  1. duivendyk

    duivendyk Guest

    Kerf has successfully implemented a 2 speed,left side drive Staton drive,by incorporating a chain tensioner in the non-driven side of the final drive to the rear wheel and adapting (as far as I can determine) a front derailleur to do the actual shifting on the driven side.This apparently is working quite well as long as you throttle back,and he deserves to be commended for this pioneering accomplishment.
    I had been thinking along similar lines with the DAX Titan,which has a 5:1 reduction on the engine itself,so that only around another 4-5:1 reduction would needed.
    For obvious reasons it would be highly desirable to have a variable transmission to the rearwheel.I thought about derailleur in the primary drive to the jackshaft,but that looked impractal due to the short chain length and limited space, but considered that a front deralleur could be made to do the shifting in the final drive and a rear one easily converted into a chaintensioner.
    Both would be mounted on the bottom side of the engine mounting plate.The rear one,on the slack (front) side of the chain only requires a simple bracket to mount it.Solidly mounting the front one,with some adjustment capability is more of a mechanical challenge but certainly doable in my opinion.
    The drive sprockets would need to be mounted on the jackshaft ,13-15-17-19t would be enough I think,giving close to a 150% range, preferably inconjunction with a freewheel.It might also be a good idea to put some reduction in the primary drive to the jackshaft
    I don't have a DAX Titan to play around with (NuVinci),so other pioneers will have to step up to the plate to advance the state of the art.
     
    Last edited by a moderator: Jul 12, 2008

  2. Looking at Papasaun's bikes when he came around his NuVinci hubs had two sprockets. A large one and a smaller one.
    Now the smaller one could drive the pedals while the bigger sprocket could drive the engine and there you have it. Do away with the jack shaft,adapt a 44 tooth sprocket over the larger sprocket which looks like about a 23 but no larger than a 30 and there you go!
    But I'll keep mine just the way it is,thank you.
    I have no intentions of going over 23 on mine and I need to pedal up those hills so I can get some kind of workout.
    I gotta lose some weight,man.
     
  3. duivendyk

    duivendyk Guest

    If you're willing to spring for a NV hub the jackshaft is superfluous.Originally the NV's had a 32t engine drive sprocket,with a 10t power take-of on the engine you have 5*3.2=16 overall,which is not too bad, and you would have an overall range of 8.5/30.
    It may be impossible to mount a larger sprocket behind the orginal 27t one,you are liable to hit the tire with the chain.If you mount it up front you run out of clearance between the chains,possibly you can still get the larger 32 t sprocket
     
  4. Even the 32 tooth sprocket might just work for I hear that low gear is pretty low on this hub.
    (edit) oops. You pretty much just said that there. :grin:
    I'm thinking now too that you'll still need that jackshaft for alignment reasons.
    Adjusting it is no problemo though.
    Just slide the jackshaft sprocket over to the right side.
     
Loading...