Abstract: A method for making bicycle frames includes a step of preparing initial parts by carbon-fiber sheets and inflatable bladders are inserted into the initial parts which are then arranged to a desired arrangement. The arranged parts are put in a mold which is heated under a certain pressure. The inflatable bladders are inflated by introducing air therein to push the carbon-fiber sheets against the inside of the mold. The carbon-fiber sheets are then solidified to form a front part of the bicycle frame. A rear part of the bicycle frame or the whole bicycle frame can also be made by the same method.

Abstract: A bicycle seat post includes two arcuate plates and a reinforcement board sandwiched between the two arcuate plates. Each arcuate plate has two lengthwise end surfaces and each end surface includes an inner corner edge and an elongate surface defined in an outer corner edge thereof. The two lengthwise end surfaces contact two opposite sides of the reinforcement board. Each of lengthwise top surface and lengthwise bottom surface of the reinforcement board is connected between the two respective elongate surfaces of the two arcuate plates so as to form two longitudinal grooves in an outer surface of the seat post.

Abstract: A handlebar structure includes a handlebar body having two end portions each provided with a first face having an arcuate convex shape and a second face formed with a recess. Thus, the arcuate convex configuration of the first face of the handlebar body satisfies the ergonomic design, so that when the user's hand holds the handlebar body, the first face of the handlebar body provides a comfortable sensation to the user's hand, thereby facilitating the user's hand holding the handlebar body.

Abstract: A crank structure includes a first combination block, a second combination block, a core layer, a resin layer, and an outer layer. Thus, the crank structure is formed by and entirely coated with the carbon fiber material without providing any metallic material, so that the crank structure has a light weight, thereby decreasing the whole weight. In addition, the crank structure is entirely coated with the carbon fiber material without forming any connection points, thereby enhancing strength and stiffness of the crank structure.