Right (rear) shifter cable broke right at the end of the cable housing ferrule leading into the shifter on my 105 STI shifter for the second time on my 6-month old bike. The first broke at 4300 miles, then again at 8300 miles today. (Leaving my 60-year-old knees with a 17-mile end-of-century ride over rolling terrain on the 11-tooth rear cog – ugh!)
LBS said when it broke the first time in April that it was a rare event. But during June’s Bike Across Kansas, they replaced at least 4 of these, all on 105s on bikes less than a year old. Shimano has told them that the problem lies with the plastic ferrule (the one that mates the shifter cable with the shifter itself) and it should be replaced with a metal one.
Wondering if anyone else has heard anything like this. Also wondering if it will really fix anything. The plastic ferrule (after 8300 miles) had a substantially elongated “hole” where the actual cable exits. If there’s that much off-axis movement, it seems a metal ferrule would abrade the cable quite a bit. But, too, perhaps that elongation allows the cable to move laterally inside the shifter, against parts or edges that abrade it. Dunno.