Sprockets Rear Chain Sprocket wont fit over Rear Brake Drum?

Discussion in 'Transmission / Drivetrain' started by SteveoSpeedstar, Jan 6, 2011.

  1. SteveoSpeedstar

    SteveoSpeedstar New Member

    Hi all,
    i bought myself a real nice old style bike a few weeks ago with the intention of buying a 2-stroke engine for it. i ended up buying the: SkyHawk Gt2B 48cc Kit.
    everything was going well until i went to fit the back chain sprocket onto the rim, unfortunatly the 'old style' brake drum is about 2-3mm to big for the sprocket to slip over. i thought of taking it to an engineer and getting the hole on the sprocket widened 3mm ...any ideas what i should do?:idea:

    check out the pics


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    Last edited: Jan 6, 2011

  2. motorpsycho

    motorpsycho Active Member

    You will need that hole in the center of the sprocket enlarged to fit over the hub.
    your best bet is to have someone precisly open the hole so that it stays centered. you could try to hog it out with a dremel and a cutting bit, but then you take the chance of making the hole off center.
    the other thing you could do, is get a different back wheel with a smaller hub.
  3. SteveoSpeedstar

    SteveoSpeedstar New Member

    Thanks for your reply motorpsycho,
    i thought of just getting a different back wheel, though this particular one has the 3-speed gears plus the back brake which i thought was a bonus.
    so yeah i think i will get someone to precisly open the hole for me.
    let you know how i went in the next few days, cheers
  4. gothicguy64

    gothicguy64 Member


    i have a better idea see .................pirate cycles

  5. SteveoSpeedstar

    SteveoSpeedstar New Member

    Sprocket Hole Opened by Lathe. for Shimano Nexus 3-Speed. Nice!

    Those Hub Adapters at pirate cycles look great! might have to invest in one down the track.
    ...i ended up getting my local engineer to open the hole for me, he did it on the lathe for $20.00. nice and neat.check out the pics! :bowdown:

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  6. SteveoSpeedstar

    SteveoSpeedstar New Member

    ohh yeah ...Sorry for posting in the wrong forum!
    now i know why i have newbie next to my name, lol
  7. wbuttry

    wbuttry Member

    is it ok to leave the the brake arm on? I could not get it to bolt to the rubbers cause it was all to much thickness and couldnt get the rubber and sprocket both on with the brake arm on there.So i had to take off brake arm. How you get it to all fit on there with the arm still there.
  8. SteveoSpeedstar

    SteveoSpeedstar New Member

    i was lucky and had plenty of room, nice clearence between the bolt heads and the brake arm and it already had a spacer/lock type washer on it. also managed to get a spring washer on it too.
    ...did have to put a little bit of pressure on the frame to slot the wheel in though, just a little say 3-5mm. ..your frame or hub may be different from mine too. i was able to remove the brake arm slip the spocket on then re-attach the brake arm. check out the pics :)

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    Last edited: Jan 19, 2011