Chris, I agree with the point about spot heating, you can set up stress points in the metal. Metal that is already stressed then has additional tortional or bending stresses while being ridden is most likely to fail in the pre-stressed region.
@ChrisNW started
London Fixed Gear and Single-Speed is a community of predominantly fixed gear and single-speed cyclists in and around London, UK.
This site is supported almost exclusively by donations. Please consider donating a small amount regularly.
Chris, I agree with the point about spot heating, you can set up stress points in the metal. Metal that is already stressed then has additional tortional or bending stresses while being ridden is most likely to fail in the pre-stressed region.