A system for fitting golf clubs to golfers that enables an overall club length to be varied without varying a length of a shaft. The system enables a greater number of combinations of club characteristics, such as shaft flex, brand, and length, to be contained within a club fitting cart and/or for a same number of combinations of club characteristics to be contained within a smaller cart.

A shaft for a golf club includes a first end, a second end, and a demarcation. The first end is adapted to attach to a club head. The second end is adapted to receive a grip distal to the first end. The demarcation is positioned at or adjacent to the balance point of the golf club between the first end and the second end.

A length adjustable golf club includes a club head attached to a shaft at a lower end. A length adjusting kit includes a shaft insert that attaches to the shaft at an upper end. The shaft insert includes a coupling port that accepts one of an extension block or a grip adapter. To provide length adjustments of the overall club length, one or more extension blocks may attached between the shaft insert and the grip adapter. A grip assembly having a reinforcing sleeve connects to the grip adapter and extends over the shaft and any extension blocks. The grip assembly couples to the shaft through a grip adapter and grip coupling. The grip adapter and grip coupling are axially moveable prior to securement with a retaining fastener. The grip coupling may be rotationally constrained or rotationally adjustable relative to the grip adapter.

A golf club includes a golf club head, a shaft adapter secured within a hosel of the golf club head, and a shaft secured within the shaft adapter. The golf club shaft is formed from a fiber reinforced polymer and extends along a longitudinal axis between a tip end and a grip end. The golf club shaft includes a tip end section, a grip end section, and a tapered section between the tip end section and the grip end section. The tapered section of the shaft includes a reference portion within the upper half that has a frustoconical shape with a near-constant taper rate, and a narrowed portion within the lower half. The narrowed portion is recessed relative to a reference surface extrapolated from the frustoconical shape.

A golf club includes a golf club head, a shaft adapter secured within a hosel of the golf club head, and a shaft secured within the shaft adapter. The golf club shaft is formed from a fiber reinforced polymer and extends along a longitudinal axis between a tip end and a grip end. The golf club shaft includes a tip end section, a grip end section, and a tapered section between the tip end section and the grip end section. The tapered section of the shaft includes a reference portion within the upper half that has a frustoconical shape with a near-constant taper rate, and a narrowed portion within the lower half. The narrowed portion is recessed relative to a reference surface extrapolated from the frustoconical shape.

An object of the present invention is to provide a golf club shaft having excellent strength. The present invention provides a golf club shaft made of a fiber-reinforced epoxy resin material comprising a cured product of an epoxy resin composition and a reinforcing fiber, wherein the epoxy resin composition comprises at least one selected from the group consisting of a bisphenol A type epoxy resin, a bisphenol F type epoxy resin and a novolac type epoxy resin, and a tetraglycidyl type epoxy resin as an epoxy resin component, and the cured product of the epoxy resin composition has a swelling ratio in a range from 20 mass % to 44 mass % in methyl ethyl ketone.

An object of the present invention is to provide a golf club shaft having excellent strength. The present invention provides a golf club shaft made of a fiber-reinforced epoxy resin material comprising a cured product of an epoxy resin composition and a reinforcing fiber, wherein the epoxy resin composition comprises at least one selected from the group consisting of a bisphenol A type epoxy resin, a bisphenol F type epoxy resin and a novolac type epoxy resin, and a tetraglycidyl type epoxy resin as an epoxy resin component, and the cured product of the epoxy resin composition has a swelling ratio in a range from 20 mass % to 44 mass % in methyl ethyl ketone.

A process for manufacturing a putter with a bi-material shaft is disclosed herein. The putter comprises a putter head, the bi-material shaft, a mass member and a grip. The bi-material shaft comprises a body with a tip end and a butt end. The body comprises a metal section extending from the tip end to a connection point, and a composite section extending from the butt end to the connection point. The mass member is positioned within an opening at the butt end of the shaft. Mass from the shaft is transferred to the club head and the mass member in the butt end of the shaft.

A process for manufacturing a putter with a bi-material shaft is disclosed herein. The putter comprises a putter head, the bi-material shaft, a mass member and a grip. The bi-material shaft comprises a body with a tip end and a butt end. The body comprises a metal section extending from the tip end to a connection point, and a composite section extending from the butt end to the connection point. The mass member is positioned within an opening at the butt end of the shaft. Mass from the shaft is transferred to the club head and the mass member in the butt end of the shaft.

A shaft 6 includes a plurality of layers formed by fiber reinforced resins. The layers include a hoop layer and bias layers. The hoop layer includes a full length hoop layer s9 constituted with a prepreg having a fiber elastic modulus of equal to or greater than 30 (tf/mm.sup.2) and having a fiber weight per unit area of equal to or greater than 50 (g/m.sup.2) but equal to or less than 80 (g/m.sup.2). The bias layers s2, s3, s4, and s5 include high elasticity containing bias layers s4 and s5 constituted with a prepreg contacting a high elastic pitch-based carbon fiber having a fiber elastic modulus of equal to or greater than 80 (tf/mm.sup.2). Preferably, the full length hoop layer s9 is disposed outside the high elasticity containing bias layers s4 and s5.