SRAM front drum brake hub

Discussion in 'Motorized Bicycle General Discussion' started by myke, Mar 26, 2009.

  1. myke

    myke New Member

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    Hello,

    New to the forum and the hobby, I don't even have a bike yet, just a motor kit, planning to buy the Schwinn Jaguar at Target unless something else comes up by the weekend.

    I picked up a SRAM front drum brake hub today at a schwinn dealer for $25. Now I am looking for rim's and spoke to assemble it for a new build. Is there some way to guess or figure out what length the spokes are I need to try and find?

    Thanks for any tips or advise!

    myke
     

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  2. ocscully

    ocscully New Member

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    There are several spoke calulators available via the internet, http://sheldonbrown.com/rinard/spocalc.xls This is a link to a good one with a pretty extensive database of existing hub and rim measurements. You need to know exactly which rims you are going to use and the # of cross you want to use any of the calulators. Your local bike shop wheel builder should be able to run the #'s for you as well.

    ocscully
     
  3. myke

    myke New Member

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    Thanks for the calculator! I will study it a bit more, but at first glance it would appear that this hub is not in that database, it says SRAM spectro on one side and it has a number 5004 engraved on the inside of the upright/anchor.

    myke
     
  4. eDJ

    eDJ New Member

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    Glad to see this posted as I'm figuring I'll have to lace a 3 over 1 wheel with a drum brake
    before long.

    Anyone know of links to sources where drum brakes are sold on the net for about $25 ?
     
  5. ocscully

    ocscully New Member

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    I believe the Sram Hub is the old Sturmy Archer. The dimemsions that you need from the hub are the Flange Dia measured from ctoc of two spoke holes 180 degrees from each other, and the center to flange distance which on your front hub should be half the distance between the two flanges. If your hub is the same as the Sturmy the Flange dia should be 90mm and the center to flange should be 27mm.

    ocscully
     
  6. myke

    myke New Member

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    Thank you very much for the detailed information! I will post back with the results when I am finished with the project.

    myke
     
  7. myke

    myke New Member

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    In the end I ended up using 10 inch spokes in a double cross pattern. The stock spokes on this particular wheel with the original hub were 10 and 3/8 inches.

    I am still not sure how I am going to mount the brake cable, this hub did not come with any hardware.

    If anyone has this hub or something similar, I would appreciate it very much if you could post a photo of the brake cable hardware at the hub so I can try and understand how to set it up.

    myke
     
  8. Large Filipino

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    Is 25 bucks the normal price for that hub or was it just laying around and the seller threw out a price?
     
  9. myke

    myke New Member

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    It was laying in the the glass case, I asked how much and they searched through about 7 catalogs looking for a price, then I said would ya take $25 and he said sold.

    They never did find it in a book and it did not come with any of the hardware.

    myke
     
  10. azbill

    azbill Active Member

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    here you go myke...hope it helps :)
    mine is a sturmey-archer x-fd
     

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  11. myke

    myke New Member

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    Thanks Bill, It's not the identical setup but it dose give me an idea I had not thought of.

    myke
     
  12. eDJ

    eDJ New Member

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    Some while back we were talking about these Shimano's and Strumey-Archer brakes
    and someone posted a $25 dollar front drum brake with cable pull activation.

    I haven't been able to find it and have spent some time looking. The thread it was in
    discussed frame and lug materials and other building hardware. The photo was from
    an online store where it was available. It looked cheap and dirty compared to the
    Strumey's and Shimano's.

    Anyone here know or remember it. Seems it was back in September to November last year.

    It looked like something that would have been made in Japan in the late 50's to 60's.
     
  13. Dan

    Dan Staff
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    #13 Dan, Apr 17, 2009
    Last edited: Apr 17, 2009
  14. eDJ

    eDJ New Member

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    Thanks Dan I appreciate that info.

    That Shimano Sport Dynamo hub looks about like what saw posted here a few months ago.
    It wasn't a dynamo but just a front drum brake, and it didn't have the quick release. Otherwise
    looked about like it though. At the time I didn't anticipate I'd be interested in one but in this
    ongoing search for stuff that would look vintage on a build, well now I wish I'd bookmarked it.

    I like that ehow article and perhaps that could be the way to go to do something with the look
    of the front axle.

    Last night I was thinking about mounting a rear coaster brake drum wheel in the front forks
    and wrapping a piece of chain around the sprocket where one end would conect to the brake
    cable and the opposite end to a return spring attached to the fork. (the cable connection would
    be mounted on the front side of the right fork tine and the return spring connected to the back
    side of it) The chain part would be secured to the sprocket by placing a small band over it
    where a small bolt could pass thru the band and hole drilled thru the sprocket to hold the chain
    in place on the sprocket. The hand brake would have similar action on the front brakei as
    pressing backwards on the pedal crank would have on the rear. As few people today have
    seen such a mechanical movement like that on a bike, it may appear vintage to them. ("Wow !
    Did they build em like that in the old days ???)
    laff

    I've figured out a way to build an old vintage headlamp but I'll save that for later. (I can save
    myself enough for the motor I want if I build most of the "faux" vintage accessories) That
    leaves having to scrounge up some old fenders, a vintage seat, and some white tires. Just
    not sure if I want to go with Olive Drab or Fire Engine Red but I've looked at Beige and Grey
    also. (I'm now researching the colors that vintage bikes would have used)
     
    #14 eDJ, Apr 17, 2009
    Last edited: Apr 17, 2009
  15. Dan

    Dan Staff
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    "Last night I was thinking about mounting a rear coaster brake drum wheel in the front forks
    and wrapping a piece of chain around the sprocket where one end would conect to the brake
    cable and the opposite end to a return spring attached to the fork. (the cable connection would
    be mounted on the front side of the right fork tine and the return spring connected to the back
    side of it) The chain part would be secured to the sprocket by placing a small band over it
    where a small bolt could pass thru the band and hole drilled thru the sprocket to hold the chain
    in place on the sprocket. The hand brake would have similar action on the front brakei as
    pressing backwards on the pedal crank would have on the rear. As few people today have
    seen such a mechanical movement like that on a bike, it may appear vintage to them. ("Wow !
    Did they build em like that in the old days ???)"

    Thats a really cool thought!!! Gonna give that a thunk eDJ. Lots of old coaster rear wheels to be had for free or next to nutton.

    I started a thread on when, like we all do, can't find a link or found one some one else was looking for. I mentioned the search for your hub. http://motorbicycling.com/f3/lost-found-7474.html
     
  16. eDJ

    eDJ New Member

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    I'm glad you like the idea Dan.

    It may be hard for some to visualize with just a description so I sketched it out.

    I omitted some of the drawing just to keep it focused to the chain pull movement and the
    Bendix brake arm defines the connection to the other fork tine so the inertia would be about
    the same as it would on the rear of the bike.

    Sketch below:
     

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  17. 2door

    2door Moderator
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    eDJ,
    Your concept looks very interesting and it should work. The only problem I see is the leverage factor. The coaster brake is designed to be activated with leg pressure and I'm wondering if you'll be able to create enough leverage with a hand brake lever to effectively expand the internal shoes to make the the brake work. If you try this please keep us posted. Very intriguing idea. I like it.
    Tom
     
  18. Dan

    Dan Staff
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    Was just thinking this would look awesome on a "rat" or "Mad Max" kind of MB. Then Hough made's bike popped in my head. Would be really cool/old world lookin' 4sho. I was thinking heat might be an issue. (Never owned a MB with coaster brakes) Tom, you have a good point. Thinking about it, could be rigged to advantage but would need twice the travel to get twice the pull. Maybe just a large sprocket?

    Just typing out loud here. Really like the thought of this. Am also thinking the chain could just be dead/bitter ended on the sprocket it self. Only has to go halfway around (or less?) to get enough purchase.
     
    #18 Dan, Apr 18, 2009
    Last edited: Apr 18, 2009
  19. eDJ

    eDJ New Member

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    Glad to hear you all like the idea. I forgot to mention in the details something called
    a "Long Pull" hand brake lever. (ever heard of one of those ?) When I first saw one it
    got me thinking about the movement above. I figured the spring would be needed to
    release the coaster brake grip so it wouldn't lock up but I may be wrong. Bitter-ending the
    chain on the sprocket might even work and that keeps me thinking of that mod Uncle Kudzu
    put up from another board for doing that too. I've never taken one of those coaster's appart to modify it but it may be the rest of the puzzle. I'd even thought of taking a thin grinding wheel
    and cutting off a tangent of the sprocket and welding a lever along that cut to increase the
    leverage from the hand brake. (still if a spring was required a hole could be drilled thru the
    sprocket and anchored thru a hole in the fork tine. (but I was thinking the chain system would
    give it a 1890 look)

    I was just figuring the spring would release the grip of the brake similar to pedaling foreward
    would release the rear coaster.

    On the amount of leverage necessary that Tom speaks of, I was wondering if the long pull brake lever (which positions the fulcrum of the brake lever further out from the handle bar making the reach longer thus increasing the mechanical advantage) would be adequate. And, what percent of the total braking would come from such a front brake system. After reading about the
    Strumey-Archer's and Shimano's in some other forums I noticed the guys claiming they could
    bring the rear wheel off the ground. I'd rather this front brake not be quite that effective.

    On my vintage motorbike design I don't want to use rim brakes with rubber pads. So, I have a
    lot of hopes for this system. With the springer I want to build, this brake, and the headlight
    this ride should turn heads real quick. A virtual eye-candy store.
     
    #19 eDJ, Apr 18, 2009
    Last edited: Apr 18, 2009
  20. Dan

    Dan Staff
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    Your 100% right, I had not thought of the need for return. Do you have a link to the "long Pulls"? If what I have found, ...think I am missing some thing. (me aslow and need pictures)



    In looking around I found this and really like the look. It is hydro/drum bike brakes. LONGJOHN.ORG - Hydraulic drum brakes on Long John bikes Am looking but not finding a way to buy em any more. Is old world lookin' and all weather but in reading, not great brakes.

    Even further off topic, but has "rod" brakes, Rideable Bicycle Replicas - Roadster
     

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