Frame Tubing & Materials Double-Butted 7005 Aluminum
7005 aluminum is an aerospace grade aluminum that is 5-10% stronger than 6061 aluminum by most measures. Double-butted tubes are specially drawn so that they are thicker at the ends of the tubes, where they are welded and stresses are highest, and thinner in the middle to minimize weight. The process of drawing and butting tubes also work hardens the aluminum. Work hardening is a restructuring of the material at the molecular level when the material is heated to a specific range, for a specific length of time, and stressed to a specific degree. Work hardening increases the strength of 7005 aluminum by roughly 20%. Double butted 7005 tubes therefore, are significantly stronger than equivalent weight plain gauge 7005 or 6061 tubes. Double butted tubing allows frame designers to build strong, but exceptionally light frames.
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