Operational loads on sport bicycles for possible misuse

Especially for carbon fiber sport bicycle frames and components the existing standards for fatigue tests don't satisfy the needs to ensure the athletes safety as numerous failure cases in field show. In order to determine realistic loading pattern for fatigue tests, operational loads for typical usage and reasonable foreseeable misuse have to be known. To determine the occurring operational loads a test bicycle has been developed. For field measurements a standardized test terrain was selected. Additionally special situations were performed to determine operational loads in so-called "possible misuse" situations. Rainflow analysis was carried out for the data mining of typical load cases. Peak forces quantify the possible misuse situations. Analyzing the operational loads related to typical use caused a Rainflowmatrix established for each point of measurement. This data is then used as basis for the development of dynamic fatigue tests on special test benches. According to the peak forces in possible misuse situations additional static tests are suggested to ensure the product safety under extreme use. The enhanced test methods suggested in this paper try to improve existing product tests by taking foreseeable misuse situations into account. The addition of static overload tests to the dynamic test protocol aims to increase the product safety, as existing test protocols don't consider high static loads. However additional field tests have to be carried out in order to approve the actual results.