Abstract: An essentially seamless bicycle frame of fiber reinforced, resin impregnated composite material and a method by which it is produced to have a top tube portion, hollow down tube portion, a seat tube portion, a head tube corner at which the top tube portion meets the down tube portion and a head tube insert is incorporated, a bottom bracket corner at which the down tube portion meets the seat tube portion and a bottom bracket insert is incorporated, and a seat tube corner at which the top tube portion meets the seat tube portion and a seat tube insert is incorporated by molding and curing of tubular preforms that were produced by rolling or wrapping layers of resin impregnated fiber material on a mandrel, each preform having been removed from the mandrel on which it was formed in an uncured tubular form. Additionally, connector tube section preforms, which are integrated into the corners, are also formed in this manner.

Abstract: An essentially seamless bicycle frame of fiber reinforced, resin impregnated composite material and a method by which it is produced to have a top tube portion, hollow down tube portion, a seat tube portion, a head tube corner at which the top tube portion meets the down tube portion and a head tube insert is incorporated, a bottom bracket corner at which the down tube portion meets the seat tube portion and a bottom bracket insert is incorporated, and a seat tube corner at which the top tube portion meets the seat tube portion and a seat tube insert is incorporated by molding and curing of tubular preforms that were produced by rolling or wrapping layers of resin impregnated fiber material on a mandrel, each preform having been removed from the mandrel on which it was formed in an uncured tubular form. For purposes of forming the corners, at least two integral flap portions are produced, on at least one end of at least one of the preforms to be joined, by axially slitting it.

Abstract: A method of molding a generally hollow front triangle for a bicycle frame of composite materials, such as heat curable structural resins. Layers of the composite material are shaped to form a front triangle shell and this shell is compressed against a mold using at least one inflatable bladder routed to the outside through a passageway passing through a modified bottom bracket sleeve or a modified head tube sleeve.