my Shiman bar end lever routs the cable outside the bar so I haven't had any problems breaking brake cables BUt I did have a mushy front brake during an EBP (Emergency Braking Procedure) a couple weeks ago. I had a car turning left at an intersection cut in front of me, casuing me to grab a handful of front brake, only to find it to not work all of a sudden. Turns out I forgot to put on one of those metal cups that go on the end of brake cables and there was nothing there to stop the brake cable from working its way into the cable hole.I think because my cable is routed externally, I haven't experienced the problem of brake cable breakage.