SRAM front drum brake hub

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

  1. eDJ

    eDJ New Member

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    Dan, this is from WIKI

    When I looked at the brake levers they had in their photos (the UK site where they were
    discussing the roller brakes and dynamo hub, the hand brakes looked about like any other
    except for the fact they stood out further from the handlebar so the lever could swing further
    in it's sweep) many of the supply sites in the USA have brake lever assemblies that are about
    the same.

    I think the difference is in the Drum having a cam which presses the shoes into the swept area
    of the drum and the friction would tend to keep the contact whereas the rim serves much like
    a disk rotor where the pads press against it. That could make some difference but I don't know from my experience.

    I've been in that LongJohn org site a few times. I think I saw some old type handle grips I liked
    there. (torpedo's)

    On that Roadster bike, it looks a lot like the Dutch bikes. Here it is after editing it some and hopefully you'll be able to see it better below. Some of these web sites seem to make their
    photos so dark you can't see them or cammo them against backgrounds that makes it nearly
    hopeless to have a clear view of what you're looking at.
     

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  2. 2door

    2door Moderator
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    eDJ,
    Giving this more thought and after reading your comment about having too much front brake, I'm of the opinion that your idea will work just fine. As for the size of the front sprocket I have to sit down with my calculator and do some figuring but my first thought is that the size of the sprocket will not have much effect on braking action. The most significant feature will be the mechanical advantage provided by the brake lever at the handlebars. As you're aware length of pull will not be the important fact here but the length of the lever itself will dramatically impact the braking action. Have you examined the rotation of the coaster brake/sprocket when applied and how much travel will you need to duplicate what you get with the backward pedaling motion used it that design? It's been a while since I've ridden a coaster brake equipped bike but as I recall you could back pedal quite a way before applying the brake; maybe a half pedal crank revolution or so. There seemed to be a lot of free-play in the coasters. Nevertheless your system could be set up to take out the free-play and run with the brake almost applied but not enough to create drag. Just some food for thought. Keep us posted. I still really like this concept and the image I have in my mind of how it would look. Very cool and mechanical.
    Tom
     
  3. eDJ

    eDJ New Member

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    Dan, 2Door.......

    The solution came to me this morning when I was ratting thru some of my building supplies
    and I found some old 1/4 inch thick phenolic board. (given to me by some guys who worked
    at a 3 phase electric motor rebuilding shop) I'll take it over to a friend of mine's who has a
    small modelers lathe and cut some 1" and 1 1/2" circles and groove them to hold the brake cable.

    I'm thinking I could make a simple block and tackle to go between the brake cable housing
    and the chain connection in the sketch. That could ampllify the effort on the brake pull (and
    to the eye-candy appeal) with a Long Pull brake lever.

    I'll revise the sketch later today so it will be clear what I'm talking about.

    If it don't look Vintage, hitll look Appalachin !

    :)
     
  4. Dan

    Dan Staff
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    Very cool eDJ. About 4 or 5 this morning, I was thinking some thing along the lines of a reverse lever. Where the working end is at the middle of the lever, not the end. Wouldn't work or be very pleasing to look at. Then thought a cable around a "wheel" from the handle turning a smaller wheel/roller to the cable brake chain. Again, not pretty but if not hidden, but accented, would look very mechanical and over engineered. ('cause it is, snork) Would multiply force and take up needed cable travel.

    How do you do those sketches, MS Paint?
     
    #24 Dan, Apr 19, 2009
    Last edited: Apr 19, 2009
  5. eDJ

    eDJ New Member

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    Dan, you could use MS Paint but I'm just using the software that came with my old Scanner. It's called
    iPhoto4. It came with a Mustek but lots of camera's used it too. It will do about everything you need
    except layer. You can splice with it though. What I like about it is that I can complete a sketch like I do here and have it done faster than I can get PhotoShop to open. (even with the acceleration plugin's)

    There are bunches of free graphic programs where you can work-up sketches quickly for free. I'll look around and post a few. I use letters of fonts from the Text to create my tires and hubs etc. The menu
    provides for straight lines to be selected or freehand. When I do these I don't even use my graphics tablet....just freehand with a mouse. (that Bendix arm gives that away LOL)

    But when it comes to rapidly prototyping a sketch (as it's difficult to "talk design") it's a handy technique.

    But this front brake idea is one of my own and the mini block and tackle idea keeps me laughing inside. Real Appalachian-Engineering that one. (as you say Snork !) I'll have to get it on Utube.

    Has anyone here tried to do that coaster to roller brake Uncle Kudzu posted yet ? I sure would like to try it with one of those.
     
  6. Dan

    Dan Staff
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    Thanks, I will look into iPhoto4.

    Your idea for this keeps making me think of an old paddle wheeler engine room I saw way back. The ship's telegraph in the wheel house was actuated and fair led in the boiler room in a similar way. Was really cool and simple.
     
  7. eDJ

    eDJ New Member

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    Well Dan & Tom, here's the latest revision with the block and tackle (luff standard 3:1 ratio)
    which should be able to draw the distance (using the Long Pull lever) to engage the brake and
    amplify the exerted hand lever pressure to render formibable front braking. (the left cable
    of the two pulleys continues into the cable housing and on to the brake lever and is thus "rigged to
    advantage" where the lower pulley moves upwards to haul the chain wrapped around the brake sprocket to apply the braking) If I can muster 20 lbs of grip with my right hand, then 60 lbs of pressure should be exerted on the coaster brake.

    Remember this is just quick sketching but it gets the idea across. When it would be in finished
    form it could look different from this. But it's enough to help visualize what I'm talking about.

    What I like most about that ships telegraph you posted Dan is that photo. I've got a speedo off
    a stationary exercise bike that was scrapped and I'd like to paint the face to look similar to it.
    Perhaps replace the needle with one that lookd more from that period. (presently it's black faced
    with green letters & numbers with an orange needle) Which looks quite 80's.

    Dan, If you're interested in iPhoto4 give me an IM and I'll talk to you about it. There are
    plenty of good free Photo & Graphics Ediotors that can do the same. Once you've done a few
    drawings with it and get the knack for it, then it becomes simple enough to use.

    But here's the sketch below.
     

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  8. Dan

    Dan Staff
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    That will work eDJ! I am thinking a large bottom sheave will take up some of the travel. (I believe it will be a minor issue, but an issue) Only go around bottom sheave then dead-end it where the upper sheave is.

    There are 6 bikes here. The only one with a coaster brake was confiscated by Carol as it was "to nice to put a motor on" LOL, She is a collector and I am a "let's tear it down and see how it works" The bike is a 1946 one owner, all original road bike (to sleepy to remember make) I am going to every goodwill/thrift shop in the state until I can find a bike with one. Am already thinking parts/bike. Like that TV ad where the woman asks the architect to design a house around a faucet.

    These lamps are for that telegraph; Antique Ships Telegraph Oil Lamps ~ Chadburns Am thinking this build with a Dax 80. Cries for a classic looking engine on a old style English bicycle, yes?

    Way OT. Found this trying to jog my memory about the confiscated bike. 1946 schwinn bicycle cycle truck with a loman diesel motor on it - Spring Hill - Sporting Goods - Bicycles
     
  9. eDJ

    eDJ New Member

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    Dan, you're right about that and I'll sketch that one too. (when I can get to it) It would
    provide an opportunity for dressing that sheave to fit the period of the 1910's if it were
    larger for sure. You'll see what I'm thinking later today.

    On that 1946 Schwinn, recently I was looking at some of the local history books that are
    showing up at the book store. These have photos from the archives of the towns newspaper
    which just celebrated it's 100th birthday and from the Local UNI's archive of local history.
    Of course I'm with an eye pealed for bicycles, motorcycles etc. I saw bikes like that one but
    without the Loman that Western Union used where they had boys they would dispatch on them
    to deliver telegrams etc thruought the downtown area each business day. That big basket and
    small front wheel must have been a standard in those times.
     
  10. eDJ

    eDJ New Member

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    Dan, here's a sketch of what you were talking about with one lower sheave where
    it is terminated to the fork where the upper sheave was in the drawing above. The
    cable housing and adjustment screw could be higher on the fork tine but in this drawing
    there's only so much space to work with.

    The sheave I used would have the shackle extended on to the chain and bolted thru the
    hole of the link so it would keep the sheave indexed to the same plane the sprocket rotates within.
    (thus eliminating any chance of it getting tangled in the spokes or requiring some cage
    or metal guide form attached to the fork tine to keep the block and tackle away from the
    spokes)
     

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  11. OzzyU812

    OzzyU812 New Member

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    That is a trip eDJ! No wonder Dan has been bugging me ALL DAY to look at it! LOL

    Why mess with the chain? drill a hole in the sprocket and use one of those brass cable stops. I belive your 1st drawing would be the strongest mechanical advantage (see disclaimer below).
    The chain may add to mechanical advantage but IMHO too many moving parts. On that note, I would be drawn to the second drawing with one large pulley. My approach has always been build it and ask questions later.

    Now I have to be on the lookout for a 26" coaster brake rim in the dump! LOL

    reddd
     
  12. eDJ

    eDJ New Member

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    :D Yeah it's one of those "Huh.....quick second look" ! things I'm designing into my build
    to give it it's own uniqueness. I mean, how often do you see a rear wheel in the front forks
    rigged to actually work ? The front forks will be a dual fork springer system as well. The head
    lamp I've designed will give the whole front of the bike it's own "wow power".

    So it leaves me scavanging the junk piles and eBay hunting for vintage eye candy to build with.

    I'm beginning to think there could be a good business in building replica's of some of these vintage
    components. Frames, springer forks (I can think of about 5 patterns), headlamps, horns, and other
    things that simply don't exist in "new" form.
     
  13. Dan

    Dan Staff
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    #33 Dan, Apr 23, 2009
    Last edited: Apr 23, 2009
  14. OzzyU812

    OzzyU812 New Member

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    Sorry, don't get me wrong I think its brilliant! I was more thinking and typing than doing the "you should do it this way" thing. I hate that. I would be so wild to have a variation of you front break mod and my rear on the same bike! I'm definitely goin to try it!

    I can hardly wait to see you bike with this mod!.ride7a.ride7a
     
  15. eDJ

    eDJ New Member

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    No worries Ozzie, all's cool :)


    I've been sending out some emails today to bicycle manufacturers to see if they would sell
    just a frame or fork sets. So far no replies.

    There are some bike frames I've found that are pre WW2 that would be ideal for me and
    I'm just trying to find a frame builders now who could produce them in small runs. But they have
    the real vintage look. I've been thinking about using these 10 speeds I've collected
    but they just won't have the "look" I want.

    So, this week end it's supposed to be quite warm and sunny here so I'll hit some places I know
    of to see what's available. It reminds me of that Johnny Cash's song about "one piece at a time".

    One thing for sure, that eye candy at eBay ain't cheap.
     
  16. Dan

    Dan Staff
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    Gonna be cool. The EDJ brake. Am I gonna have to pay royalties?

    snork
     
  17. eDJ

    eDJ New Member

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    I still want to check out Uncle Kudzu's brake where the interior is welded together so
    it becomes a roller brake instead of a coaster brake. That way it will be more of a
    drum brake with the characteristics of one.

    I'd hate to see the EDJ brake become known as the motorbicyclist "launcher". But I guess
    everyone running one could super glue a bed spring atop their helment.

    Can you imagine that Dan ? Someone says, "Hey look at that guys helment with the big spring" !
    And another replies "Ahhh yeah, he's running onea those crazy ol EDJ brakes". :D

    This should be worthy of an animated emoticon. (where the guy goes over the handlebars, lands on
    his head and bounces back onto the seat of his bike and keeps going) LOL
     
  18. sellouma

    sellouma New Member

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    WAW!!!looks awsome!
    that is exactly what I'm looking for!
    do you think it would fit on an Schwinn Stingray chopper fork?
     
    #38 sellouma, Jan 14, 2010
    Last edited: Sep 12, 2010
  19. azbill

    azbill Active Member

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    yes it will fit, between the forks,,,I am not sure if you can find a ready-built 24" wheel with one tho :(
     
  20. sellouma

    sellouma New Member

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    it's all right, i will take my 24'' wheel to the bike shop and have them install it .
    thanks for the info
     

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