Alu

Aluminum alloys have lower density and lower strength compared with steel alloys (both are reduced by approximately 2/3). Also, in contrast to some steel and titanium alloys, which have clear fatigue limits, there is no clear limit of stress below which aluminum will not fail due to fatigue. However, proper alloying, good mechanical design, and quality construction practices ensure that aluminum bicycle frames have acceptable life spans. Furthermore, aluminum can be used to build a frame that is lighter than steel and will never rust.