Abstract: A head tube for a bicycle frame is aluminum alloy, is formed by stamping an aluminum alloy sheet, which may have an equal thickness or may be a special-shaped sheet having an unequal thickness, and has a rear side, an outer surface, a seam, a soldering layer and at least one bossed pattern. The seam is formed longitudinally on the rear side of the head tube. The soldering layer is formed in the seam of the head tube. The at least one bossed pattern is formed on the outer surface of the head tube and is non planar with the head tube. Because the head tube is formed by stamping, the at least one bossed pattern with intricate edges or corners can be formed easily on the outer surface of the head tube with low manufacturing costs to give the head tube an appeasing aesthetic appearance.

Abstract: A bicycle frame has a front frame, a lower bracket assembly, an upper bracket assembly, a rear frame and a shock absorber. The front frame has a head tube, a down tube, a bottom bracket shell and seat tube. The lower bracket assembly is connected pivotally to the bottom bracket shell and has a lower connecting bracket. The upper bracket assembly is connected pivotally to the seat tube and has two upper connecting brackets. The rear frame is connected pivotally to the upper connecting brackets and the lower connecting bracket of the upper and lower bracket assemblies and has an upper fork, a lower fork and two dropouts. The shock absorber is mounted pivotally between the upper connecting brackets and the lower connecting bracket.