Coaster to Drum Conversion

Discussion in 'DIY Home Built Motorized Bicycle (non kit)' started by UncleKudzu, Aug 19, 2008.

  1. UncleKudzu

    UncleKudzu New Member

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    Reprinted with gracious permission from original submitter, bikebuilder, from this thread . many thanks to bikebuilder!

    Someone asked me to explain how to do this. This particular brake setup is the easiest to modify. The one on my bike was more difficult. The center mass or the "ball" on this one is in two peices. All you have to do is weld the two peices together so that it cannot reset it's self while riding. Reassemle the hub and weld a lever on to where the gear used to be with holes front and back. front for the hand lever and the back for a spring. Make sure that the lever you weld on is in the best position possible to work with the hand lever.

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    The one on my bike had the ball in one peice already but did not have that little peice sticking out between the pads to hold it in place. This would allow it to reset. So I had to weld a little nub on the ball.

    This conversion works pretty good. I can leave black marks with the one on my bike. The one I put together for "little brother" 195lbs would lift the back tire off the ground.

    You can see it in use a little watch the video linked in the rat-rod swingbikes post

    ratrodbikes.com • View topic - Rat-Rod swingbikes
     
  2. UncleKudzu

    UncleKudzu New Member

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    Reprinted with gracious permission from original submitter, bikebuilder, from this thread . many thanks to bikebuilder!

    (below is response to this question: "ok, after thinking about this i have a question: why isn't the forward motion of the wheel enough to throw the hub back into "drive" after braking? you can brake and coast, brake and coast with the hub on the rear, so why not on front? i'm not understanding why any internal weld is needed.")

    [​IMG]

    The area with all the dots on it is the main focus. On the bike I ride this was one peice and the "nub" where the blue dot is did not exist. I made one. On this one the "ball" is in two peices which allows it to reset so in a rear coaster situation it can be activated at all times. when using it as a drum brake if you let the brake reset. you will get one good stop and then it will reset. The brake arm where the gear used to be will change position and you won't be able to activate it again. Back to this brake. I will just have to remove the spring holding the ball together and weld the two peices together along the green dots. I fully anticipate lifting the rear wheel on the bike this brake is going to be on. The key is that the the part above or behind the area with the dots does not change it's relationship to the cable and lever.
     
    #2 UncleKudzu, Aug 19, 2008
    Last edited: Aug 19, 2008
  3. trackfodder

    trackfodder Member

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    originally I set my latest bike up with a rear wheel in front and used a chain and spring to brake with the longest motorcycle lever I could find. After I assured myself the brake was a piece of sh--I spoked up a Schwinn rear drum brake with the ratcheting sprocket removed. My chrome plater enjoyed it but it isn't cutting it either. However, I noticed it is installed on the wrong side. I don't know yet if that makes a difference. I just naturally used the same hole I poked in the fork for the coaster brake arm. I think I was better off in the 7th grade on my first one sticking my shoe soles on the naked tire.
    I'll bet you think the squids on the crotch rockets invented "Stoppies"
    Keith (trackfodder) Williams
     
  4. jak stoll

    jak stoll New Member

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    verry inventive

    are you able to get good power out of it?
    Ive found shimano coaster hubs take a while to seat in so you probably want a good warn one

    the bendix 70 & 76 were good hubs back in the day (downhilling before front brakes sorta)

    thanks for the nice email
    take care
    JAK
     
  5. Roadkill

    Roadkill New Member

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    That looks like a good idea for slamming the brakes. Is that why you did it and did it work? Can you still use the hand brakes as well as the drum? I wonder if you also added disc brakes if you would stop on a dime or the tire would just explode/tear to shreds!
    Would this work with friction drive systems or would it ruin the clutch? I am new at this and want to make a nice little rocket myself.

    Kidding good luck and let us know. Cheers
     
  6. diceman2004

    diceman2004 New Member

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    Thats a real slick mod . I had that idea rattling around in my head , but wasn,t sure if it would work . then i saw your post . thanks for the info . I,m gonna try it out now that i seen how its done . Makes for a nice small clean brake setup . way to go man .
     
  7. MarksA-C

    MarksA-C New Member

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    I must be slow... I can't really understand how it works. Can anyone "dumb" it down for me?
     
  8. silverbear

    silverbear The Boy Who Never Grew Up

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    I'm with you on this one. It looks like a really good idea, but I'd like to see photos detailing the how to and what wheel is being worked on. This would be a really good thing to share. Would the parts have to be welded? Is there any other way to do this? Could brazing work? I don't weld, but if I knew exactly what to do and maybe even printed out pictures then I could take a hub or two to a local welder and have him give it a shot. I like this idea a lot.
    SB
     
  9. dash

    dash New Member

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    sounds cool, could we have more detailed plans please!
     
  10. bairdco

    bairdco a guy who makes cool bikes

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    i plan on making one of these soon. when i do, i'll make a full step-by-step.
     
  11. flmotorbikes

    flmotorbikes New Member

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    I would just by one since it might get a little complicated with the bearing set up
     
  12. bairdco

    bairdco a guy who makes cool bikes

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    another thread raised from the dead. i actually made one, and it sucked. hardly any stopping power. looked cool, though.
     

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