Thursday, December 15, 2011

Weak Link no more!

Way back in October I described how ridiculously weak the replaceable rear derailleur hanger is on most bike frames, and said I planned to machine my own out of steel. Well, it didn't happen as quickly as I might have hoped but it's finally done:

A few of you have asked me if I could make a few extras while I'm at it.  Sorry, but this was done with old-school machining methods, not CNC, so it was very labor intensive. I'm not even making an extra for my own pit bike. Hopefully, Wheels Manufacturing can be convinced to make them for us - they make quite a few variants, but not one that fits my bike - yet. Maybe if enough of us inquire...


  1. Aren't derailleur hangers meant to be that way so that they break rather than your much more expensive frame or derailleur itself?

  2. Justin - yes, that is the theory. In practice, most are designed to bend or break so easily that they cause far more carnage than they prevent, by bending after just the lightest impact, or twisting from the load caused by mud stuck in the derailleur cage. A bent or broken hanger then allows the derailleur to tangle with the spokes of the rear wheel - which destroys both wheel and derailleur and leaves you running for the pit or out of the race. Your typical replaceable hanger could be 5X stronger and still perform its intended function of saving your frame or derailleur from expensive damage, while remaining straight and true under lighter loads or impacts

  3. This may be a silly question as I'm not a materials scientist or MechE, but should the steel used for the hanger be softer than that of the frame, so that it gives before the frame does? Or why not use a stronger aluminum alloy than currently used? Economics might hinder this idea, but what about Ti?