FITTING FOR SHAFT TORQUE
Torque is the twisting force that changes the rotation of an object around an axis or a point. It's affected by the moment of inertia of the object. The measurement unit of torque is distance multiplied by the force applied. In physics terms, torque is a vector that is the cross product of two vectors. In golf, we care about torque in the downswing where we want the shaft to resist the twisting force of the clubhead as we increase our swing speed into impact. It's about accuracy.
Shaft torque is typically determined by clamping a lever arm at the shaft tip then attaching a weight to the end of the arm. The amount of shaft tip rotation is measured in degrees. In the jargon of torque measurement, greater resistance to twist will be measured as a low number of degrees (low torque number), and lesser resistance to twist will be measured as a high number of degrees (high torque number).
Since each shaft manufacturing company may have it's own way of measuring torque, it can be difficult to compare the torque values of shafts produced by different manufacturers. Staying within a single family of shafts allows you to feel the consequences of different levels of overall torque on performance of a club for your swing.
Typically, shaft torque is given as a single number for the shaft tip. However, torque is somewhat independent of flex (stiffness) and it can vary at different regions of the shaft depending on the choices made by the shaft engineer regarding production technique and materials used. Torque and stiffness can be designed to enhance feel and provide stability that can be matched to your swing characteristics.
Torque is one of those shaft specifications that has been somewhat misunderstood and somewhat mis-applied in considering the fit of a shaft to a golfer's swing. The marketing of torque has promoted low numbers as most desirable, but low-torque shafts often have a harsh or "boardy" feel. On the other hand, early graphite shafts with high torque values were often "whippy" and unstable at higher swing speeds. Modern shaft technology has moved beyond these limitations.
Knowledgeable incorporation of torque considerations into clubfitting benefits all golfers. Research into the role of torque on shaft performance has revealed significant effects on ball trajectory, shot dispersion, and feel. There is no question about these effects when shaft fitting is done using appropriate and effective methods.
At JTCLUBS we use a specialized instrument that allows us to measure shaft torque at different points along the length of a shaft and develop a graphical representation of a torque profile. By having the ability to measure torque accurately, we can compare shafts from different manufacturers and bring precision to fitting for torque.