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Cable on front derailleur keeps getting damaged
#1
I have a Shimano "050" front derailleur, and every few months, the cable is breaking - always at the same location at the point where it is tied to the clamp (which is held by the bolt on the derailleur).

I am using top routing, and here are the instructions as published by Shimano:
http://techdocs.shimano.com/media/techdocs/content/cycle/SI/Tourney/FrontDriveSystem/SI_6DK0B/SI_6DK0A/SI_6DK0B_En_v1_m56577569830607106.pdf

The following image shows how Shimano recommends the cable to be installed, and that's how it is on my bike.
[attachment=4875]

The problem is that when the cable is pulled (to move to the higher gears), the pulley moves up and forward, and therefore the cable gets bent at a very small radius as all the force is being made on that clamp. Therefore, the cable gets bent on every shift, and after a few hundred shifts, it breaks.

By the way I'm using Jagwire cables so they shouldn't be bad (or so I'm told).. so what can I do? Is replacing the derailleur the only option?
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#2
You could try sanding a small bevel onto the area of the clamp that really digs into the cable as it pivots. Perhaps if it spreads the bend out over at least a few millimeters it may prevent it from causing the wires to break. You wouldn't want to radically change the pivot point of the cable as it could affect the shifting. But I don't think it would hurt anything to round off that corner so it doesn't make such a sharp bend in the cable.
  Reply
#3
Thanks for the tip. I tried rounding it down using a bench grinder, and it still seems to be shifting just fine. Hopefully now the wire will last a bit longer
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