A new shift concept for the engineers....

Discussion in 'Motorized Bicycle General Discussion' started by ferball, Jul 26, 2010.

  1. curtisfox

    curtisfox Well-Known Member

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    In the motor bike picture sec. Page 4 Herry form germany Check out his hub it apears to be driven from the left. I asked how but he never responded back. It is a coaster brake 3 speed. If I could find one to play with love to see if it could be done
     
  2. curtisfox

    curtisfox Well-Known Member

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    I have 2 of them bought from ScotorParts4less and both have crocked clutch drums.Seems that the threads were put on the shaft at a angle. I don't know if it makes that much diferance but I suspect some exses clutch wear. Do you have one? check and see if yours wables. They are neat because they have a built in 5 to 1 reduction gear box on them plus the vareable drive
    PS I am going to put mine in the lath and streight it the best I can.
     
    #42 curtisfox, Jul 28, 2010
    Last edited: Jul 28, 2010
  3. ferball

    ferball New Member

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    Even if all that comes out of this discussion is a new rear sprocket that accomodates to sizes, it would be nice. Even if we never figure out how to shift them, having that versatility would be nice. The cost I would guess should be pretty close to what a single machined sprocket would cost.
     
  4. bairdco

    bairdco a guy who makes cool bikes

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    it could also be done manually. if you had a stacked sprocket set-up and a functional, spring loaded chain tensioner, you could easily stop, pull the chain off one sprocket and switch it over, letting the tensioner spring forward and back.

    it'd be good for going from street to trail or flatlands to canyons, or wherever a lower (or higher) gear was needed.

    i was thinking of my old Honda CT-90, '67 i think, that had a sprocket on both sides of the rear rim. for trails you had to switch the wheel around.
     
  5. silverbear

    silverbear The Boy Who Never Grew Up

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    There you go. Would it be as good as or as convenient as a derailleur type of shift kit? Of course not, but is it better than no options? You bet it is! Just two sprockets to choose from in my case would do it. One for cruising at 25 to 30 and the other a bit lower for hilly riding with speeds of 15-20 or 20-25 or so would make a world of difference. Keep it simple, manual, inexpensive and bulletproof. It would be a winner and I'd be first in line to buy one. OK, second in line. Ferball is first.
    SB
     
  6. KCvale

    KCvale Active Member

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    I agree completely.
    Even if it isn't practical it would be cool ;-}
     
  7. max350

    max350 Member

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    Here it is your shift koncept! its possible to have 3 sprocket if i bending the fram a little
     

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    #47 max350, Jul 28, 2010
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  8. Creative Engineering

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    There it is guys...max350 has shown that the kit sprockets can be stacked...and that they do fit.

    The sprocket fixture is in the CNC, so tomorrow I'll make some sprocket clusters for HD 410 chain.

    SB, ferball, I'm figuring on clusters of 3. For me I'm going to do 44/40/36. I'm thinking a 4 tooth span is going to work with a deraileur.

    SB a 48/44/40 might work good for you based on the speeds you want.

    Ferball...you may want to go with a 44/48/52 for yours, for hill climbing.

    Decide what you would want yours to be; between now and in the morning. Then send me a P.M. This may be a one-shot deal, so choose wisely. :D

    Jim
     
  9. silverbear

    silverbear The Boy Who Never Grew Up

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    Awesome. I'm in and have sent a PM.
    SB
     
  10. NEAT TIMES

    NEAT TIMES New Member

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    Interesting Thread.

    In Regard To Releasing Clutch To Shift.

    Back In The `60`s I Drove A Mack 18 Wheeler With A Tri Plex Tranny System. Two Shift Levers, A 5 Speed And A 3 Speed Gear Box.

    The Only Time I Needed To Use The Clutch, Was While Stopped. No Gear Grinding Involved, Very Smooth.

    Thanks Jim!!

    350 - COOL!!

    Ron
     
    #50 NEAT TIMES, Jul 28, 2010
    Last edited: Jul 28, 2010
  11. ferball

    ferball New Member

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    Here is another angle to attack the shifting from. Instead of copying the rear derailer for shifting, why not copy the front derailer, less moving parts, and I imagine it would hold up a lot better, and then make a separate spring loaded tensioner piece. Not to mention that most motor bike chains on the left side are above the chain stays not below it making the rear derailer useless...
     
  12. curtisfox

    curtisfox Well-Known Member

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    I had the same thought. But everything on the right hs to be reversed. So the front derailer used on the left would have to be on the bottom. Could be done use a seat post tube flaten one end so you could bolt it the the axel and another small bolt to hold it from turning. ( or weld it ) It would hang down low but should work. Then you could use part of a rear derailer for a tensioner closer to the front. Just my thought...Curt
     
  13. Creative Engineering

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    I did manage to get over to the metal drop center today.

    I bought a small sheet of 11 gauge, (.115"), 304 Stainless Steel...enough to make 9 sprockets of various sizes.

    I sheared it up into the appropriate size squares for sprockets.

    I had planned on getting them into the machine today, but ran out of time.

    Tomorrow I should have the three clusters finished. (2) 52/48/44 & (1) 44/40/36 for my own use.

    Even if I have to make some sort of deraileur type mechanism...I'm sure this is going to work.

    Practical? Affordable? I seriously doubt it. If the sprockets could be made cheaply...it might fly.

    I have tried both a waterjet, and a laser for cutting sprockets. Neither process is accurate enough.

    A wire E.D.M. would be accurate enough with the benefit of being able to stack and cut 20+ at a time.

    Cutting steel sprockets on the mill is just too slow to be practical. I cut all of the sprockets for the Spoiler build...It takes 3X as long to cut steel sprockets of the same tooth count in Aluminum.

    Jim
     
  14. ferball

    ferball New Member

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    I should have a 50t sprocket soon, I was going to swap out my 44 but I was looking at my Bike today and I have some serious space between the chainstay and the wheel. ( I figure it is to accomodate larger tires being a MT Bike and all) So I am going to try and stack the sprockets. Which would make the sprockets affordable if we just stack individual sprockets, but they would be aluminum...
     
  15. Creative Engineering

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    The clusters that I'm going to make will be made up of individual stainless steel sprockets. I'll put a spacer between them, and sandwich the whole thing so that all three sprockets run true to the hub adapter.

    Jim
     
  16. ferball

    ferball New Member

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    i wish i had a shop......
     
  17. Creative Engineering

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    laff Trust me sir...It's far more trouble than fun!

    If I were wealthy...It would be fun to have my shop for hobby stuff. :D

    To try and make a living at it...:-||

    Jim
     
  18. Creative Engineering

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    Ferball,

    If I get the whole mess working right...I will try an Aluminum cluster just to see how well it holds up.

    I'm not really worried about the wear that might be caused from shifting...It's more that I'm thinking large diameter sprockets made from thin Aluminum may flex. We'll see...I wanted to try steel to start with to give the whole idea a fighting chance.

    Stainless wasn't necessary; I could have used mild steel. I just figured if these are the only ones ever made...they might as well be stainless. :D

    In the end...if the Aluminum does hold-up...it could be a viable product.

    Jim
     
  19. silverbear

    silverbear The Boy Who Never Grew Up

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    I was out on my motorbike today thinking about the sprocket cluster. I was riding along on a 50CC China Girl mounted on a 60's Schwinn, less powerful than the 68CC motors I usually run, but also quieter. I came to a few hills and at each one assisted the motor with pedaling and imagined instead that I could shift the chain to a different sprocket and climb the same hills without effort. It has never been about high speed for me, but more power meant better hill climbing. With gears I don't need to worry about squeezing out every bit of power possible since the gears can make the difference and save the motor from working too hard. I am really hoping this can become a viable and affordable product for anyone with a simple single speed coaster brake hub.
    So the sprocket cluster will bolt onto your sprocket adapter, is that right? And a derailleur of some kind will guide the chain onto the chosen sprocket. I'm guessing then that disengaging the clutch will not be necessary. I can hardly wait to try it.
    SB
     
  20. curtisfox

    curtisfox Well-Known Member

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    I am with SB that would be KOOOOOOL.
    Sick bike gets $200+ for the shift kit yours should not be out of line. Just thinking?
     

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