68 Spoke help, Ragjoint just isnt working

Discussion in 'Motorized Bicycle General Discussion' started by RoadPocalypse, May 6, 2011.

  1. RoadPocalypse

    RoadPocalypse New Member

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    Ok so the bike I have, has a set of 68 Spoke wheels. I think they are Micargi wheels. I have tried everything and now im looking for ideas or suggestions here. I did finally get the sprocket on so it is as true as can be. The problem now is, its pressed against the bearing surface so much it creates alot of drag on the wheel. This simply will not work and lead to premature bearing failure in short order.

    Pirate Cycles is out of the Sprocket for these, so can anyone please shed me some light here or a source to get the correct sprocket for these wheels?
     
  2. Mac

    Mac New Member

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    Contact sportscarpet on this forum,he may be able to help(spelling may be wrong on the name)

    Mac
     
  3. wayne z

    wayne z New Member

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    On my last two builds, I used a spacer washer(machine bushing from Home depot) with 1.75"id 2.25od between the sprocket and hub, after drilling the holes in the sprocket, hub and washer. Then I chamfered the sprocket holes and used chamfer head screws to bolt it down same as the pirate's sprocket.

    I cheated though, I have a Pirate's sprocket to lay out the holes on the kit sprocket with.
     
  4. Venice Motor Bikes

    Venice Motor Bikes Custom Builder / Dealer/Los Angeles

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    If you want to use the stock sprocket & rag joints?, you have to have a 36 or 72 spoke wheel.
    Those Manic Mechanic sprockets that Pirate sells aren't all they're cracked up to be... When bolted on as Jim designed, they don't leave enough room for the chain to clear the tire. :(
     
  5. wayne z

    wayne z New Member

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    I use the stock sprockets on 68 spoke wheels by just drilling the 4 bolt pattern that matches with the pilot holes on the wheel hub and using 1 3/4 id x 2 1/4 od spacer washer(Home Depot)\ between the hub and sprocket to clear the spoke ends.

    The M M sprokets work fine with 1.195 tires. I used them on 3 builds in the last 3 months, until they ran out of stock, and I was forced to figure out another way.
    Now I use the stock sprockets and save a lotta money not buying 1.195 tires or the MM sprockets anymore.
     
  6. wayne z

    wayne z New Member

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    I don't see how it could press on the bearing surface, unless the hole in the sprocket is too small or the dust shield hasn't been trimmed smaller.
     
  7. gobigkahuna

    gobigkahuna New Member

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    Wayne - Do you have a photo of how you did it?
     
  8. wayne z

    wayne z New Member

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    I will take some pics and post them tomorrow.

    When I first dropped the stock sprocket on my wheel, I saw that the sproket center hole almost fit snugly on the machined stub on the wheel's hub. About .010 slack. I could center it exactly with 3 thin strips of paper card inserted at equidistant points when placing the sprocket.

    The sprocket doesn't fit flush to the flange because it is resting on the spoke ends at the hub perimeter.

    You can buy a stock, redimade,zinc plated washer that fits perfectly in the narrow space between the spoke ends and the machined stub of the hub.
    The sprocket bears on this when bolted, and clears the spoke ends.

    This washer is 1.5 id and 2.25 od. You will also need to accquire four flathead allen bolts, m6x20 and locknuts or 1/4 x1" sae. I had wrong measurements for washers in the other posts.
    it, and the space that it fits is only3/8" wide and has to have four 1/4" holes drilled in it, so layout has to be pretty accurate.

    Once the sprocket is drilled, I clamp it to the hub with the washer in place and clamp it with small c clamps and the paper strip centering shimis in place.

    Then I take a drill and 1/4 bit and just barely drill the the washer thru the sprocket holes, to get a mark similar to a center punch. Or use a transfer punch if you got it. Mark the sprocket and flange for orientation.

    Drill two opposite holes in the washer to 1/4 ". reassemble parts and align 2 washer holes along with sprocket holes with the 2 factory holes in the flange. clamp it all and drill , chamfer,and bolt the 2 holes. I use a 1/2 " bit for chanfering the holes.
    Then remove clamps and drill/bolt other 2 holes.
    Sometimes the nuts will interfere with the tack welds behind the flange.. Grind a 45 deg chamfer under 1 flat of the nut to clear the weld bead if needed.

    I carefully grind the dust cover to a small enough dia. with a bench grinder so that it barely clears the sprocket hole, and put it in place before the brake arm.

    Whole process takes me less than 1 hour.
    Hope this helps.

    Wayne
     
    #8 wayne z, May 6, 2011
    Last edited: May 6, 2011
  9. RoadPocalypse

    RoadPocalypse New Member

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    Wayne, your method sounds more like what I need to get done. Pics would be awesome. You know, I didnt trim the dust cover, I didnt know I had to so that could be my problem. Back to the drawin board :)
     

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