Drumbrake,compatible with telescoping fork ?

Discussion in 'Spare Parts, Tools & Product Developement' started by duivendyk, Mar 28, 2008.

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  1. duivendyk

    duivendyk Guest

    I am thinking about going to a Sturmey Archer drumbrake/hubgenerator front brake combo but am wondering if this is a safe thing to do,the reaction force from the braking is applied to only one leg of the front fork by the reaction rod from the brake and I am not all that sure about the mechanical integrity of the telescoping fork as found on current mountain/comfort bikes.Does anybody have relevant knowledge and/or experience on the subject ?.Pushing the envelope where brakes are concerned may not be the smartest thing to do,you may do it only once,JJ

  2. ocscully

    ocscully Member

    Most of the forks available today are set-up to take a disc brake, so I don't think that the braking forces will be any problem. Where I think you may run into some problems is the clearance between the fork leg and the outboard side of the brake. And pretty much the only way to find out is to try the hub you want to use in the fork you are going to use.

  3. fetor56

    fetor56 Guest

    To my way of thinking if everything is connected to everything else then a force applied to one part is equally(mostly equally) distributed amongst the FULL unit.
    Like ocscully said as long as the brake you choosing is physically compatable with the forks there shouldn't be any problems.It's a big $ investment so by all means do more homework and please start a thread if u go ahead with this project.I'm interested to do this myself and as soon as i get some spare dough i'll be following......it's my dream brake. :cool:
  4. HoughMade

    HoughMade Guest

    That is a great point that most forks are designed to work with disk brakes- they would apply force to one leg of the fork only as well- great analysis, oscully.
  5. azbill

    azbill Active Member

    I have well over 2000 miles on my X-fd front hub
    I had it on Haro mtn bike for at least 700 mile...never felt any different flexes or anything
  6. KilroyCD

    KilroyCD Active Member

    I have a Sturmey Archer "Steelite" drum brake on the front of my '46 Columbia (with over 300 miles on it) and it has the repro Schwinn-style springer fork. I can say that there are no difficulties, as the arm is only locked to the one leg of the fork. The braking action itself applies the pressure in the hub, not on the arm, and is equally distributed by the axle to both sides. As a result, it will not pull to one side, or flex more on the side the arm is on.
  7. Scottm

    Scottm Guest

    I have the S-A XFD on my springer forks. The arm that attaches to the forks is 6 inches long from the axle to the tip of the arm if that helps. That's a great question BTW.
  8. duivendyk

    duivendyk Guest

    Re: Drum brakes,regrettably,KilroyCD is misinformed,the axle has no role whatever in transmitting the reaction torque from the braking action to the forks,how could it via the ballbearings?,as the brake shoes are forced against the drum,the mounting plate that carries the shoes&actuating mechanism attempts to rotate with it,unless it is somehow rigidly attached to the fork(s) .In this manner one fork leg has to absorb all the bending force,and in turn transmit it to the bike frame proper.It is fallacious to say that because the brake force ultimately acts on the entire bike everything is OK, as somone else has stated.It's like saying if someone hits me on the head with a baseball bat,my cervical vertebrae will transmit the force to the rest of poor me !,so what is there is to worry about ?(only a fractured skull ?)
    My bike was designed for cantilever brakes as evidenced by the mounting studs,not for drum or disk brakes.It is quite likely that these work perfectly fine with these forks,but the inescapable fact remains that the telescoping front fork was not designed for this application.I don't have a clear picture really how it is constructed,(two sliding tubes with a spring in between).If it was a solid fork I would feel more comfortable with it.If you query the manufacturer,I guarantee you they won't commit themselves and tell you that you're on your own,JJ
  9. KilroyCD

    KilroyCD Active Member

    I stand corrected, and my apologies for giving incorrect information. :oops: My S-A Steelite drum, however, has not caused any problems regarding fork twist. I suppose that the fork, despite being one of the aftermarket Schwinn-style springers, is strong enough. Also, the S-A Steelite drum isn't capable of as much braking power as cantilevers or caliper brakes. That, I'm sure, is a contributing factor.
  10. frameteam2003

    frameteam2003 Member

    most mo-peds use a telescoping forks and drum brakes---so it can work--how strong is your fork is the question.My guess is it's strong enough but you will have to secure the brake tork arm in a good manner so not to cause problems.
    I plan on using the same hub for my bike but my forks(webb girders) were designed for this hub.Ordered a new S/A dimo-brake from Harris---$95 shipped.