New shift cable damaged after clamping to shifter

Question

I just replaced all the cables and housing on my bike and was annoyed to discover on close inspection that the front derailleur cable has sustained some damage from the cable clamp on the derailleur:

It looks like maybe 3-4 strands broke.

Background: I don't know if the cable was stretching in real time, or if I just hadn't fully seated all the ferrules prior to the initial clamping. But as I was adjusting the derailleur and running through gears, I found it was getting more slack. So I did have to unclamp the cable, pull the slack through, and reclamp it a couple of times.

I'm used to seeing cables flatten and unbraid a bit under the clamp, but I've never seen strands break like this from over-clamping. I'm wondering if there's a burr in the clamp that cut them.

Admittedly I do tend to clamp all cables quite tight. I.e. clamping shift cables as tight as brake cables.

Does the damage below indicate I did something wrong?

Or is this just bad luck/ cable quality?

And is it OK to continue to use this cable anyway? The broken strands are after the clamp so I don't expect them to result in a cable failure, but wondering if I'm missing something.

Thanks.

Answer 1

That's disappointing but not going to upset the function of the derailleur.

The most significant effect is that you'll have a hard time reusing this cable if you pull it in the future - a stray strand like this makes it hard to re-insert into an outer.

If you have the front mech fully dialled in and will not need to undo this cable for years, then its also feasible to trim it right here leaving no spare. However that makes any future adjustments impossible.

How did it happen? Looks like the wire makes a full 180 turn around the pinch bolt.
If you're pulling the free end downward with pliers while tightening the pinch bolt, there will be one strand taking the most load right at the corner. In this case, the load was more than one strand could take and it parted. There may have been a slight weak point right there, and if it was reusing an old cable that has already been pinched in the same area then pre-existing damage is likely.

Personally, as long as the mech works, I wouldn't worry about some broken strands on the free side at all. The main risk is stabbing yourself with a pointy strand, but that's not likely here.