Been there done that....sux big time.I broke mine at the Powerline Park GNCC race and then figured it was broken a week later. I'm not sure how long it was broken for though... I had a hell of a time getting the primary off of the crank and then had an even harder time getting the broken bolt out of the crank!! I had another machined bolt for the Ironman GNCC race and have since ordered a new bolt from STM. I hope I never have to revisit this problem again!!! EVER!