Engine behind seatpost?

Discussion in 'Motorized Bicycle General Discussion' started by UncleKudzu, Sep 26, 2009.

  1. UncleKudzu

    UncleKudzu New Member

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    my latest idea for the bike i never actually finish is a slightly stretched frame with the engine sitting on the extended chain stays. lower center-of-gravity, less obvious engine, shorter drive chain, and easier clearance for peddling are the advantages i'm imagining. sort of a cargo stretch with an engine is what i'm picturing.


    has anyone done this yet? any reasons why it's a bad idea? feedback please (even Walter's).
     
  2. Kevlarr

    Kevlarr New Member

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    I can almost picture this, stretched frame with say an S curve in the seat post with the engine between the seat post and rear tire.
     
  3. UncleKudzu

    UncleKudzu New Member

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    yes! think of something like the Surly Big Dummy with an engine sitting in the triangle behind the seatpost.
     
  4. UncleKudzu

    UncleKudzu New Member

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    something like the rough illustration below. maybe something along the lines of those Micargi stretch cruisers, but with taller rear stays...
    [​IMG]
     
  5. bbb

    bbb New Member

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    mine has it with friction drive
     

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    #5 bbb, Sep 27, 2009
    Last edited: Sep 27, 2009
  6. UncleKudzu

    UncleKudzu New Member

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    thanks, bbb! that's very close to what i'm imagining. and now i have a picture to help me day dream/plan :)

    that just seems like a good place for the engine.
     
  7. bbb

    bbb New Member

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    Common ? i get is about it being off center...never noticed it at all and it is only 5lbs or so.
    In fact...when on its side stand it has more of a tendency to want to fall over the opposite way.
     
  8. Elmo

    Elmo New Member

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    Something like this?
    Elmo
     

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    #8 Elmo, Sep 28, 2009
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  9. Elmo

    Elmo New Member

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    Here is my recumbent in progress.
    Elmo
     

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  10. skou

    skou New Member

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    just want to post a pichture of a danish made moped with the engine in the same spot where you plan to place yours. Imageshack - skodir0.png
    also ive got a frame of the same type where i plan on installing a ht engine sometime in the future
     
  11. UncleKudzu

    UncleKudzu New Member

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    Elmo, skou, bbb... thanks, y'all! yeah, that's what i'm talking about.

    see, i couldn't pedal without beating up my ankles on my first frame choice. then, the engine sat too high on my second choice (top heavy). it just seems like it would be an overall good solution to put my little Morini low and in back.

    hey, Elmo, might you have a bigger photo of that blue bike? looks like maybe it started life a tandem , huh?
     
  12. Elmo

    Elmo New Member

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    Uncle Kudzu
    That is not a real bike. I had about the same idea as you do and took a pic of a tandem and spliced it up with MS Paint. I sent the pic to Neat Times to get his reactions to it before I started to hack & weld. My idea is to take two similar frames and cut one behind the seat post and cut the other in front of the seat post and join the two together with some 4130 chrome moly tubing I have left over from building my recumbent. But joints and brazing.
    No motor in the way between your feet and the back can have a rack on it and bags on the sides if you want them. Also it seems to me that the balance wold be better. The chain line wouldn't be as long as my toureasy clone and Ive built 4 of them with no problems with the chain or shifting. Hope this helps.
    Elmo
     
  13. UncleKudzu

    UncleKudzu New Member

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    sounds like a cool plan! i'd like to see thar come together.

    i did a Google Image search for "longtail bikes" and saw some cool cargo/long bikes. WorldBike even has some open source plans for cargo bikes. look at their Chop n' Drop.

    exactly! keep us posted on your project. thanks for your input!
     

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