Originally Posted by
Looigi
Wet road grit can serve as a nice abrasive paste between the cables and guide or BB. You'd likely make it through many cables before making it through the BB, but IMO given enough cables, time and shifting, it would be inevitable.
I suppose it is possible, after all, even water cuts through miles of solid rock eventually as witness the Grand Canyon. However, it must have required a lot of shifting with gritty cables to do this. I have a '96 Litespeed with 70,000 all-weather miles on it and the original plastic Shimano bottom bracket guide is still in good shape.