A final question related to my cable change... Everything went off without a hitch and the bike shifts and brakes 100% better with the new cables and shifters. However, I didn't have a file handly to clean up the ends of the brake cable housings. A little nub of metal is sticking up, though I pushed it out of the path of the cable with a nail. Does that little nub pose a risk to the cable in terms of gradual fraying and possible failure? I can always untension the cables and touch up the housings, but if it's nothing to worry about I'll let it be.