Shaft Flex Ratings
There are five different flex ratings: X, S, R, A and L. X is extra stiff, S stiff, R regular, A originally meant amateur but now denotes senior, and L ladies. These different ratings are based off of different swing speeds and strengths.
Swing Speed and Shaft Relation
Swing speed determines the best possible shaft for the golfer. Golfers who swing around 90 mph with their driver should look at using a regular shaft. Senior flex is appropriate for swing speed of about 80 mph, while those with a slower speed should use L flex shafts. When swinging faster than 100 mph, use a stiff shaft. And for those who swing extra hard, upwards of 110 mph, use extra stiff shafts.
The most common shaft materials are steel and graphite. Steel shafts are more common and are the most durable shaft material and provide superior control over shots. However, steel shafts are heavier than graphite so they do require a higher swing speed in order to get distance. Graphite, while less durable than steel, is much lighter. The higher flex and lower weight of graphite shafts mean they provide superior distance. Choosing steel or graphite is based on personal feel and performance, and many golfers end up using graphite shafts for drivers and steel shafts for their irons.
There are some other high-end specialty shaft materials on the market, such as Nanofuse shafts that combine elements of both graphite and steel shafts. These shafts use a nanocrystalline alloy and a carbon fiber polymer to provide a lightweight but rigid shaft.
Kick points in shafts are where the shaft flexes most. These points affects the trajectory of the ball upon contact. The higher the kick point in a shaft the lower the ball trajectory for that club.
Torque refers to the natural twisting motion of the shaft during play. All shafts have some torque that is measured by the degree of twisting. The lower this number is, the less torque is experienced in the shaft. Most iron shafts have a rating of 3 degrees. The higher the degree of torque the more flexible the shaft is likely to feel during a swing.
Golf shafts affect accuracy, trajectory and distance of golf shots. Picking the proper shaft for a golf club is essential to maximum output of the club--and golfer.