Originally Posted by
arc
An interesting item has quietly emerged for road racing bicycles made of carbon fiber. Professional Tour deFrance level cyclists can apply above average stress loading to their cycles (rough road conditions, frame flexing, high speed judders, oscillations, resonance etc). The frames have been examined and found to have developed microscopic fracture lines not visible to the eye but detectable with ultrasonic tools used for testing pipes in the steel industry. Carbon fiber sheet is composed of millions of very thin threads "bonded" into place with epoxy resin. Individual fibers can break and/or de-laminate over time. Both of these materials are technically "inert" and as such ideal for manufacturing items that wont "rust", but oxidization is just one element of industrial processes, chemical bonding and slow degradation of certain chemical elements over time is normal. Carbon fiber is flexible when in sheet form, the glue "epoxy" is the "solid" part of the process, epoxy breaks down over time and will develop micro fractures when repeatedly exposed to stresses such a when used to connect/interface to metallic components. The micro fractures are normally not a concern due to the combined flexibility and high number of carbon fibers in the sheet, unless the cycle is used for more than 4 years...