Car wheel with rear drum brake on a BMW airhead

Discussion in 'Hacks' started by Jim K in PA, Sep 25, 2014.

  1. Jim K in PA

    Jim K in PA Long timer Supporter

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    Has anybody seen or done a rear car wheel conversion on an airhead BMW with a drum brake? Would love to see pictures, especially of the drum. Is there a car or trailer brake drum compatible with the BMW brake shoes?

    I am imagining an adapter machined to mate the wheel (Centerline 15x3.5) with a brake drum, rear spline cup, bearings, and drilled for the axle.

    Easier option would be to convert to a rear disk and mount the rotor to the adapter, rather than a drum.

    Weighing options on what to do with Olga's wheels. Opinions welcome.
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  2. Bobmws

    Bobmws Curmudgeon At Large

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    Had to look back at your thread to see the rear wheel as it is. I envision clearance issues installing / removing a wheel with the car tire in that two sided swingarm.
    #2
  3. Jim K in PA

    Jim K in PA Long timer Supporter

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    Legitimate point, Bob. Unless the drum is centered within the wheel, it won't even go IN the swingarm. Conversion to rear disk looks like the only option for what I am envisioning. The disk hat & rotor would mount on the left side of the whee, partially within the dish.

    If I go this route, I'll sketch something up and perhaps turn a test adapter out of wood to confirm the design. I can't turn the adapter itself as I do not have a metal working lathe.
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  4. hack2004

    hack2004 Been here awhile

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    I have had a 135 15 r Michelin on my 1975 R9100/6 ural rig for over thirty years. The rim has heavy duty stainless spokes and drum brake and clears the swing arm with a bit of body language . Chris at Boxermetal mounted new stainless car rims and spokes in 2013 for me,:clap:clap:clap:clap

    Attached Files:

    #4
  5. hack2004

    hack2004 Been here awhile

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    I have had a 135 15 r Michelin on my 1975 R9100/6 ural rig for over thirty years. The rim has heavy duty stainless spokes and clears the swing arm with a bit of body language.:clap:clap:clap:clap
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  6. Jim K in PA

    Jim K in PA Long timer Supporter

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    Ok - I guess I was not clear on what I was asking about. I was not talking about adapting a wheel and car tire to my spoke hub. I have that now. I am considering going to a disk wheel like the Centerline I mentioned. My rear wheel needs to be rebuilt/re-spoked, so am looking at all options.

    Hack2004 - gorgeous rig. I am impressed that you have a 135 in there. My 125 just barely clears the swing arm as it sits. My swing arm was already narrowed and plated at the fat part of the tire radius for clearance.

    I also see that you have Brembos on the front, with what appear to be non-BMW rotors on adapters. What are the rotors from?

    Thanks for the input.
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  7. hack2004

    hack2004 Been here awhile

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    Front rotors are rcb on my original /6 front hub
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  8. whitham_wannabe

    whitham_wannabe Long timer

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    Something like this?

    [​IMG]
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  9. Jim K in PA

    Jim K in PA Long timer Supporter

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    VERY interesting! Can you share some details? It looks like the original hub was somehow was mounted to the centerline disk wheel.

    :ear

    Is that Chris' old rig?
    #9
  10. Jim K in PA

    Jim K in PA Long timer Supporter

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    :huh

    Sorry - rcb?
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  11. hack2004

    hack2004 Been here awhile

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    EBC rotors
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  12. SLACKER

    SLACKER Been here awhile Supporter

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    vagabond.......
    http://www.expeditionportal.com/for...decar-R100-Paris-Dakar-Enduro-Sidecar-Rig-EML

    I think it was built by that cat Chris (530.520.7856) out on the west coast............BOXERMETAL........but I am not sure...........If you join expeditionportal.com you should be able to track down whoever did the centerline drum brake conversion definitively...........Good luck and show us what you find!........I have a GSPD Replica which I may want to do something similar to down the road.....just gotta payoff a few other projects first
    #12
  13. Jim K in PA

    Jim K in PA Long timer Supporter

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    Ah - what application? Were they spaced out from the stock hub to allow the calipers to clear the spokes?
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  14. Jim K in PA

    Jim K in PA Long timer Supporter

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    Yep - thought so. I've been on expo portal for years. Thanks for the reminder/confirmation.
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  15. whitham_wannabe

    whitham_wannabe Long timer

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    Yup, Boxer Metal Chris' build. I can take some photos if you like, but his build photos linked above will probably give more insight.

    But ... if you have the skills and the desire, it can be done!
    #15
  16. Jim K in PA

    Jim K in PA Long timer Supporter

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    Thanks. I am going to talk to Chris directly, as well as Woody (wheelworks), and perhaps Claude as well. I am trying to tie down a path forward that includes rebuilding or replacing my wheels (I have spoke "issues") as well as the front brakes. I had hoped it would be an easy path to replace a pair of obsolete single sided calipers with a pair of common dual/four piston brembos. Not so easy. I may just use a more readily available single sided caliper. I have no issues with braking performance. I just can't locate pads or parts for what is on the bike now.
    #16