I took my giant tcr adanced for a loop Saturday. Near the end of the ride I heard a banging from crank. At 1st I thought I was just hitting the cadence sensor. The road was busy and it was a while before I stopped. The magnet in the end of the pedal of the crank scratched the heck out of my giant tcr advanced. Any suggestions. Bikes usually break near top tube. But I am concerned for cosmetic and safety issues.