Shaft torque, or as it should
most accurately be stated, shaft torsional stiffness, is the property of a
golf shaft to resist the twisting forces placed on it as a natural part t of
swing the club.
During the golf swing, the
shaft bends and twists. The amount of bending and twisting in a shaft if
dependent first on how stiff the shaft is from a flex and torque standpoint,
and second, how much bending force is placed on the shaft be the golfer. If
the shaft is very torsionally flexible (15 degrees or more torque) and the
golfer is very strong, it is possible the clubhead could twist enough on the
down swing that the clubface would arrive at impact significantly open of
closed.
It was this type of
observation made in the early days of graphite that led the golf equipment
industry to form the opinion that a shaft with a high degree of torque was
bad for accuracy while a shaft with the low of torque was good. From this
assumption came the shaft industry's desire to control the torsional
stiffness of the shaft, which was achieved in the middle 1980s with new and
added strong materials. In the past 10 years, as more research has been
performed in the area of torsional stiffness shaft designers from the
standpoint of stiffness, that torque does have an effect on the flex-feel
of the shaft. Between two shafts of equal stiffness (as measure by frequency
oscillation), the shaft with the lower degrees of torque will play and
feel stiffer.
Effects on Golf Shotmaking
Performance Factors
Does a
shaft with a lower degree of torque hit the ball straighter?
Yes, but only very slightly and to a level of improvement that can only be
measured through the use of mechanical swing machine testing. To contrast
then, does a shaft with high degree of torque hit the ball crooked? No, it
doesn't, given a few logical facts. Today, the highest degree torque shafts
that are produced under traditional shaft design parameters have
approximately 7 degrees of torque, which is a far cry from the 15 degrees
shaft made in the early days.
A better example of whether
torque has an effect on accuracy is found on the PGA Tours where the
vast majority of graphite drivers shafts do not have torque rating of
less than 3 degrees. Moreover, none of the other ultra graphites in use on
the PGA Tours are made with less than 3 degrees. And these are some of the
world's most powerful swings using these shafts.
But what
about the role of Torque at impact?
If the golfer hits the ball the ball off-center with a 7 degrees torque
shaft, won't the torque allow the head to twist open or close and cause the
ball fly off-line? High speed-photography at impact has shown that the time
of impact with the ball is so short (0.001 second), even with off-center
hits, that the clubhead does not have the time to rotate open or closed to
hit the ball off-line due to the torque of the shaft. It is true that when
the ball is hit off-center, more of a twisting force is placed on the shaft
than if it is hit on the center of the clubface. But it is also a fact
supported by True Temper's Applied Research Laboratory that the ball is away
from the face before the shaft can twist the face open or closed.
Because of the principle of
horizontal bulge on the Driver and fairway wood-face, a shot hit off the toe
and heel of a wood head will cause the head to rotate about its own Center
of Gravity (CG) much more than causing about the shaft. When the head
rotates about its own CG as a result of an off-center hit, the ball will
roll across the face before it takes off, in the process picking up some
amount of hooking (toe shot) or fading (heel shot) sidespin.