PSA for my fellow rim brake riders who use carbon forks
I ride a 2017 Cannondale CAAD12 rim brake with the original fork that I purchased second hand in 2023. Today I saw that the front caliper had shifted so I went on to clean and then tighten the bolt that hold the caliper. As per Shimano spec of 8-10Nm (https://si.shimano.com/en/pdfs/dm/BR0003/DM-BR0003-09-ENG.pdf, page 13), I put 9Nm onto my torque wrench and started tightening. Much to my horror, I never got to 9Nm and found this instead:
Needless to say, a new fork has been ordered. Kinda strange touch to hold a part in your hands that had the potential to kill you.
The bottom photo was taken after applying 7Nm of torque.
No idea what exactly caused the failure. When I bought it used in 2023 I found a couple of bolts severely over tightened. Maybe that caused an initial crack that worsened over time. Happy to have caught it now though while it was still a problem that can be fixed with money.