Wednesday, May 29, 2013

Now I know

I wondered if the newer Shimano brifters with the cables routed under the bar tape would be less prone to shred the cables and put the whole expensive mechanism at risk of an incurable jam.
Now I know.

This bike was introduced with the usual, "there's something wrong with my rear shifting." I popped the cable housing out of its stops so I could get enough slack to examine ferrules for damage. Then I rolled back the rubber hood and there was the rat's nest of frayed cable.

This bike isn't that old. The customer bought it on the Internet from Bikes Direct to the Repair Shop. He brought it to us to have its initial problems ironed out, which apparently included having 5 mm housing installed from the right shifter to the frame stop. The rest of the housing is stock cheesy 4 mm.

Because the housing is buried under the tape, a mechanic can't cut the damaged cable right outside the shifter. I had to extract damaged cable from the housing. Fortunately I could do this without unwrapping the bars.
Digging with a fine-pointed, curved pick I was able to pull forth a loop of wire I could make larger by pulling with needle-nose pliers. A broken strand did kick up a little down the length of the cable, but not enough to jam in the housing.

After I smoothed the tangled strands of the piece of cable in the shifter I cut it close and worked it gradually down through the mechanism with the needle-nose pliers.
Pushing the cable was made harder because the rubber hood does not want to peel back completely clear of the opening. That makes it more of a pain to do a routine cable change, let alone the delicate extraction of potentially damaging shards.
So: the new cable routing on Shimano brifters does NOT reduce the fatigue on shift wires and does NOT make extrication of a broken wire much easier, if at all.

Keep an eye on those cables!

Maybe crap like this is supposed to make electronic shifting look like a good idea. Then instead of complaining about cables going out of adjustment at an inopportune time you can complain about your batteries going dead.

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