Shifting???

Discussion in 'Motorized Bicycle General Discussion' started by Bikewithamotor, Nov 20, 2009.

  1. Bikewithamotor

    Bikewithamotor New Member

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    Hi, I have a stock 44t rear sprocket which maxes out on the road pretty quick. So...I mounted a 24t right next to it. The engine doesnt have enough power to start going in this gear, so I was wodering...

    Does anyone know of a good way of shifting gears? (Please not the 250 dollar shift kit!)

    Homemade designs are sweet if you have one!!!

    Thanks
     
  2. Ghost0

    Ghost0 New Member

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    The standard kit is only $180, but I hear what you are saying. My initial attempt at a shift kit was to use a derailleur on the left side to try to make a three speed. Didn't work out very well because when you try and bump start the engine the derailleur would unwind, loosen your chain and it would fall off. I am sure others will have some ideas for you though.
     
  3. Creative Engineering

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    I would like to see your set-up with the 24T mounted right next to the 44T. Do you have pics?

    Jim
     
  4. Riding Rich

    Riding Rich New Member

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    Search google for "Jackshaft / Shiftkit / Freewheel"

    I have a thread out there that might give you some ideas.

    It's not completed totally.

    Someday i'll finish it.

    I don't know about cheaper though.
     
  5. NEAT TIMES

    NEAT TIMES New Member

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    A Sbp Shift Kit Or A Cvt Belt Box Is The Best Thing You Can Do For Any Motor. I Weight 0ver 300 And My Titan 49cc With Shifter (sbp Shifter Pieces) Amaze`s Me Every Time I Ride. Motor Developes Awsum Torque With Out A Lot Of Rpm`s. If You Could Test Ride A Shifter Bike, That Would Be It!! A Shifter Build Is Better Than Any Mods. Ron
     
  6. Pablo

    Pablo Master Bike Builder & Forum Sponsor

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    You could wait for our dead of winter sale! zpt.shft.
     
  7. BarelyAWake

    BarelyAWake New Member

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    orly? o_O

    oops Pablo - you may have just postponed a purchase lol :D


    Bikewithamotor - not to dissuade any DIYers, but after a buncha research I've found the SBP's shift kit isn't as expensive as it seems - when you add up all the costs of the various parts (the freewheel sprocket on the crank being one of the biggest) and all the effort in R&D... it's actually quite reasonable and you know it'll perform.
     
    #7 BarelyAWake, Nov 21, 2009
    Last edited: Nov 21, 2009
  8. Pablo

    Pablo Master Bike Builder & Forum Sponsor

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    Late Dec-Jan time frame...
     
  9. Riding Rich

    Riding Rich New Member

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    Pablo

    That's great news.
    I'm on a limited budget till after christmas.
     
  10. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    I don't think the stock engine will pull a 24T on a 26" bike anyway.
     
  11. Maxvision

    Maxvision New Member

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    I'd save my pennies and go with SBP's shift kit. Just put one on a bike for a customer and it's sweet as can be. With his 3 speed nexus hub he can start in first gear without pedaling and in third, with a good flat road and a back wind he can hit close to 50 mph.

    Be safe when you ride at those speeds. All we're going to need is a few dumbasses killing themselves (or someone else) then bingo, new laws will no doubt be passed.
     
  12. xlite

    xlite New Member

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    Absolutley true. Even a 28t is close to worthless, even on a slant with expansion pipe. If 24t did work the difference between 24 and 44 is too much for any deraileur anyway.
     
  13. Russell

    Russell Active Member

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    I'm not sure how the math works. It seems that any two sprockets next to each other on a hub, must be sized so that they match the pitch of the chain for proper shifting.

    I have no idea how great the difference in tooth count in two ajoining sprockets, could be.
    If I were able to figure all that out I would fab a two or three max cluster.
     
  14. NEAT TIMES

    NEAT TIMES New Member

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    When I Looked Carefully At The 7 Speed Cassette Off A Regular Pedal Shifter Bike, There Is Much More To It Than I First Thought. There Are Ramps To Move The Chain Up And Other Mods. It Is Not A Simple System. Ron
     
  15. Bikewithamotor

    Bikewithamotor New Member

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    Yeah...i'm kinda tight on cash right now so I'm wondering if for now I should just have the 24t sprocket mounted...use the 44t normally, and when I come to a flat stretch just hop off and manually shift the chain over. (I could have a little pouch behind the seat of tools I would need to take the slack out of the chain) Its a pretty foolproof idea and what I'm doing is just taking that extra power from my engine and putting it to use. I recomend that you do this yourself because as you can see in the attachment, there is plenty of room for a smaller sprocket on the average bike. :)

    What do you think?
     

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  16. MaxPower

    MaxPower New Member

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    It took a fair amount of R and D but I'm pleased with how my transmission turned out. I'm going to take the motor off and put a 4 stroke on it just as soon as spooky tooth gets them in stock. I'm having reservations about the grubee 4g box but I know Roland is a stand up guy and will replace it if its crap. He said his kit is going to cost 250-300 dollars. As far as shifting is concerned, I'll never go back to single speed. can't wait to see SBP 4 cycle shift kit. peace.
     

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  17. toker_ace

    toker_ace Member

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    Lets build it right here in the kitchen! LOL! I ordered my jackshaft a couple of days ago. I'm like a kid at christmas. Just two more days. I'll keep ya'll posted.
     
  18. Maxvision

    Maxvision New Member

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    First Tandem I've seen with a motor on it MaxPower. I bought an old rusty tandem last summer with plans to put 2 motors on it. You've re-inspired me to do a little more planning on it...Thanks

    Dug out my photoshop prototype. .weld.

    tandem2.jpg
     
    #18 Maxvision, Nov 26, 2009
    Last edited: Nov 26, 2009
  19. MaxPower

    MaxPower New Member

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