A method of manufacturing a composite rim includes following steps of: disposing a composite material on an outer surface of an air bag to form a semi-formed rim, wherein the air bag is a completely closed annular tube without any through opening on the outer surface and contains a thermal expansion material thereinside; disposing the semi-formed rim in a mold; and heating the thermal expansion material so that the thermal expansion material expands and inflates the air bag and the semi-formed rim is then solidified.

A crank arm for a bicycle may include a body extending along a body axis and having a first body end and a second body end axially spaced apart from the first body end. The insert may also include an insert provided toward the first body end. The insert may include a base portion having a radially outer surface. At least one extension may extend outwardly from the radially outer surface and may be encased within a corresponding recess in the body whereby relative planar movement between the body and the at least one extension in a first plane. The retaining portion may have a retaining portion width measured in the first direction and the retaining width may be greater than the throat width thereby inhibiting relative radial movement between the at least one extension and the recess and preventing radial extraction of the extension from the corresponding recess.

The present disclosure provides single-piece objects and methods for forming such objects. Such single-piece objects may be bicycle frames.

A crank arm for a bicycle may include a body extending along a body axis and having a first body end and a second body end axially spaced apart from the first body end. The crank arm may also include an insert provided toward the first body end. The insert may include a base portion having a radially outer surface. At least one extension may extend outwardly from the radially outer surface and may be encased within a corresponding recess in the body whereby relative planar movement between the body and the at least one extension in a first plane orthogonal to the radial direction is restrained. The retaining portion may have a retaining portion width measured in a first direction and the retaining width may be greater than a throat width thereby inhibiting relative radial movement between the at least one extension and the recess and preventing radial extraction of the extension from the corresponding recess.

A method of manufacturing a carbon fiber wheel rim is provided, including flowing steps of: preparing a core ring, including a core material which is disintegrable and annular; continuously obliquely winding at least one first dry carbon yarn around the core ring, to form a first semifinished rim; placing the first semifinished rim in a mold, and performing vacuuming, resin injection and thermoforming, to form a second semifinished rim; removing the second semifinished rim out of the mold, and disintegrating and removing the core material.

A fiber composite laminate having one or more fiber layers, comprising a first laminate region and a second laminate region. In the first laminate region, the fiber layers of the fiber composite laminate are impregnated with a thermoplastic elastomer material. In the second laminate region, fiber layers of a first lamina of the fiber composite laminate are impregnated with the thermoplastic elastomer matrix, and fiber layers of at least one second lamina of the fiber composite laminate that is positioned on top of the first lamina are impregnated with a thermosetting polymer matrix.

A reinforced molding is formed having an internal continuous fiber reinforcement preform embedded therein. Continuous reinforcing fiber is deposited in a reinforcement volume to form a continuous fiber reinforcement preform, and the reinforcement preform is then located within a mold of a molding apparatus. The mold is loaded with flowable and substantially isotropic molding material, e.g., by injection with heated and/or pressurized resin. The molding material is hardened (by curing or cooling or the like) to overmold the continuous fiber reinforcement preform. The resulting reinforced molding surrounds the internal continuous fiber reinforcement preform with a hardened substantially isotropic molding material.

A bicycle wheel has a wheel frame. The wheel frame is a hollow and annular frame and is composited by multiple equally sized wheel bars. Each one of the wheel bars has two halves connected to each other to form the wheel bar, and each one of the two halves being made by laminating, heating and forming a thermoplastic prepreg. The equally sized wheel bars are connected to each other to form the bicycle wheel.

A method for making a bicycle crank arm includes (a) providing an inner frame unit, (b) winding a first bundle of unidirectional continuous fibers on the inner frame unit to form an intersecting pattern, (c) impregnating the intersecting pattern with a curable resin material to obtain an impregnated structure, and (d) molding the impregnated structure in a mold.

A method of manufacturing a carbon fiber wheel rim is provided, including flowing steps of: preparing a core ring, including a core material which is disintegrable and annular; continuously obliquely winding at least one first dry carbon yarn around the core ring, to form a first semifinished rim; placing the first semifinished rim in a mold, and performing vacuuming, resin injection and thermoforming, to form a second semifinished rim; removing the second semifinished rim out of the mold, and disintegrating and removing the core material.