Gravity bike project

Discussion in 'General Bike Discussion' started by cbman, Apr 12, 2010.

  1. cbman

    cbman gnar! gnar! gnar!

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    OK, so I was looking around the internet and found a branch of biking called gravity biking. This is where people ride these small, aerodynamic bikes with no pedals down huge hills. I then found a site where a guy flipped a bmx frame upside-down to make one of these cool bikes, and thought I would try it myself. I don't have any bmx bikes but I do have a 13" Gary Fisher tarpon. I removed the chain, switched the headset bearing cups, and flipped the forks. I also put a different set of handle bars on so they would be lowered, put the old rack on upside-down to act as a seat, and have yet to remove the cranks. I also added some foot pegs. I did some geometry and the trail measurement on the flipped frame was triple that of the normal frame. This will make the bike excellent at what it was made for, being extremely steady at high speed in strait lines.
     

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    Last edited: Apr 12, 2010
  2. Industry_Hack

    Industry_Hack Total noob (& forum admin) Admin Staff Tavern Member

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  3. cbman

    cbman gnar! gnar! gnar!

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    HAHA everyone's like "you are so going down on the thing" it's much more stable than it looks... I hope.
     
  4. Doohickie

    Doohickie Older than Hack

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    Before you ride this thing downhill, watch this.[ame="http://www.youtube.com/watch?v=ZNwmpLPhoHw"]Bicycle Downhill[/ame] The good bit starts at about 45 seconds in. It brings Industry Hack's comment into perspective.
     
  5. fleeter

    fleeter The Bearded Wonder

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    won't your rear wheel pop out once you hit a good bump?
     
  6. cbman

    cbman gnar! gnar! gnar!

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    no because the rack is attached to the frame and the rear skewer so even if it does loosen the wheels can never fly off
     
  7. Industry_Hack

    Industry_Hack Total noob (& forum admin) Admin Staff Tavern Member

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    The wheel doesn't need to fly off to cause issues. If it even shifts in the dropouts...

    Can I sign your cast? ;)
     
  8. Doohickie

    Doohickie Older than Hack

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    45 seconds in, I'm tellin' ya...
     
  9. retromike3

    retromike3 retromike3

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    gravity bike?

    I built a gravity bike out of a BMX bike. I used plates I had bolted to the bottom bracket to rest my knees on and a set of arrow bars for the front. Mine worked grate and I took it down the steepest hills in town. The only problem I had was that I would go though a pair of TUFF Pads(I used two front tuff wheels) every time I used it and I had to wait quite a wile before the pads stopped stinking. It was going so fast that they would melt.

    This particular bike is set up as a joke right? You cant rest on the crank unless your into pain and maybe this is not the right forum for that kind of behavior.

    Mike Frye
     
  10. TxCyclist

    TxCyclist Administrator Staff Member Admin Staff

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    So how do you sit on that cycle?
     
  11. Techninja

    Techninja New Member

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    I dunno maybe I'm Crazy like CB is but I actually see this thing working. While the frame is higher he'll be laying lower on it which should help the center of gravity issue if not actually improve it from a standard bike. Sid he has yet to remove thje crank, Which means it's coming off solves the issue brought up earlier A good set of brakes and it'd be set I'm behind him on this working
     
  12. Farnsworth

    Farnsworth New Member

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    Dude that looks nuts. Did you try it? The guy in the video bit it pretty hard.
     
  13. funetical

    funetical Slowin it up.

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    How did I miss this thread? It looks like that thing would rip you open if you didn't do it just right.
     
  14. Tarukai

    Tarukai SMILEY CAR

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    Not gonna lie, that looks so fun. However, I would wear MX armor and an off-road full helmet rather than a regular bike helmet, lol.
     
  15. funetical

    funetical Slowin it up.

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    What's up Tarukai? Haven't seen you in a while. Right. I think it's more dangerous than standard safety options could cover.
     
  16. fleeter

    fleeter The Bearded Wonder

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    ...which makes me wonder why the guy in the clip wasn't wearing a face shield... I thought that was pretty dumb
     
  17. Industry_Hack

    Industry_Hack Total noob (& forum admin) Admin Staff Tavern Member

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    Will we all get to sign his cast?
     
  18. retromike3

    retromike3 retromike3

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    cast?

    I was thinking more like signing the guestbook at his funeral. If you actually ride a bike with no saddle and no pedals. With the bars pointed down and sharp bits pointed at your groin I don't see that as a sport with much of a future.


    Mike Frye
     
  19. funetical

    funetical Slowin it up.

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    The future of gravity biking will be a generational thing. It's like learning to fly, a lot of people have to die to get it right.
     
  20. Industry_Hack

    Industry_Hack Total noob (& forum admin) Admin Staff Tavern Member

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    Ouch.