Up to 70% of golfers hit the ball with an open club face. This causes reduced flight distance and has an adverse effect on direction. How can we help golfers achieve a square impact? Development of the GN502 series started with this question. A head with features for reliably gripping the ball. This was the common design concept for the driver, fairway woods, and irons.

At the same time, development of a specialized shaft for the GN502 series was also undertaken. The leader of this project was Masayoshi Ogawa from the Development Dept.

Excellent grip. This was not just a design concept for heads, we also applied it to shafts. Through further utilizing head features and increasing synergistic effects, we can allow golfers to achieve a square impact. This means that, by allowing for easy striking of the ball and also inhibiting power loss, 70% of golfers are able to utilize their full true potential. In addition, flight distance is further increased if features for increased head speed and striking the ball strongly are added. For the specialized shaft of the GN502 series, we were aiming for these characteristics.”

The bias type sheet consists of diagonally intersecting carbon fibres. The straight type sheet consists of horizontally arranged fibres. The hoop type sheet consists of vertically arranged fibres. Carbon sheets includes these three types. Mr. Ogawa explained each of these types to us while forming sheets into fine cylindrical shapes.

“Bias sheets relate to torque. Straight sheets determine bending and hardness. Hoop sheets control collapsing and restoration when the shaft bends. The manner in which these sheets are combined and how much of each and where determines the shaft characteristics.”

What specifications were used the specialized shaft of the GN502 series?

“70% of golfers have an early release type swing with a fast grip speed, so we thought about a design which would utilize these characteristics. Through whipping and bending at the hands (bat side), the timing at which the head is returned when a golfer's downswing begins is slowed down. We did this so that, even with an early release type swing, natural power will be created through the shaft. With bent shafts, one disadvantage is that they also tend to collapse easily. If they remain in a collapsed state, the face will remain open and speed will not be achieved. This is where the previously explained hoop sheets entered the design picture. Despite bending and whipping, by preventing excessive collapsing and providing quick restoration ability, a strong release is achieved. In order for golfers to utilize this effect, hoop layers are utilized in the entirety of the specialized shaft. This is the first prominent characteristic of the shaft."

A specialized bias sheet was also developed. The average thickness of one conventional sheet is 0.125 mm, but this was successfully reduced by 0.075 mm. An enhanced bias layer extensively layered to the degree that the width of one sheet could be reduced was achieved, and elasticity was increased.

The GN502 series specialized shaft, through the effect of straight layers and hoop layers, produces the appropriate amount of bending and whip and makes return speed easier to control and adjust. Bending and whip return is quick and the release is strong, so head speed and a square impact are easy to achieve. Enhancement of the bias layer allows for the ball to strongly fly off the club. Development of the GN502 specialized shaft marks the birth of a unique shaft with all of the above characteristics.

Drivers used to hit the ball off the tee and fairway woods and irons used to hit the ball off the ground surface differ in their characteristics. Mr. Ogawa also explained these differences.

“For hitting the ball off the ground, it’s necessary to have more rigidity at the end of the club than with a driver. This is because it’s necessary to try and achieve more stability with the head. By doing this, the face angle is maintained.”

Further detailed development of iron shafts was pursued. The shaft design is tailored to each iron so that shafts are lighter and softer for longer irons and heavier and harder for shorter irons. The overall result is that each iron can be swung with the same timing and the ball can be reliably gripped.

The GN502 series includes a surprising variety of specifications. The GN502 iron specifications include the M-43, M-40, M-37, M-34, and the M-30. Not only is designed tailored to each individual iron, but designed is also tailored for each set of specifications. Designers imagining various combinations results in extremely high precision design.




Through these interviews, we gained an excellent understanding of how the GN502 series, through synergistic effects produced by the head and shaft, allows for increased head speed and flight distance by making it easy to swing, grip the ball, and keep power loss at a minimum. (End)