Square Drivers in 2007
Square drivers are designed to hit the ball straighter by providing stability at impact. Nike’s Sumo2 square driver helped K. J. Choi win the AT&T Memorial tournament today, July 8, his sixth on the PGA Tour.
As reported in Golfweek a few weeks ago (and touched on in the Klees Golf Blog, 12/6/06), Nike tested the Sumo2 using a mechanical robot for hours. The robot hit both conventional and square drivers and the results were unequivocal: the square drivers hit the balls straighter.
Straighter ball flights were duplicated when the drivers were swung by human golfers. However, good results were also a function of matching the right shaft with the square head, with the right loft. Getting fit for a square driver insures that you get the most out of this technology.
The head of Nike Design and Testing, Tom Stites, presented an excellent example of how to understand square driver technology:
“Think of a wide wheel base sports car. The wider the base, the more stable the car is around turns. [Wheels installed away from the body of the car are like extending the arms of the ice skater in a spin: the shift of weight away from the center of gravity slows the ice skater’s body down, or reduces a race car’s tendency to spin out around turns.]
Filling in the squares of the corners of a golf club head [is like widening] the wheel base of the sports car. If the mass of the club head is distributed to the extremes, the club is better equipped to resist any offcenter destabilizing force (offcenter hits). If the club more effectively resists changing its face angle during the three or four milliseconds of impact, it will send the ball less offline. It will also impart less side spin to offcenter shots.”
Stability at impact can be achieved by a variety of means besides squaring the corners: Slowing down one’s swing speed reduces head twisting; lower torque shafts can have that effect. Movable weights and using a combination of materials with different weights (carbon/titanium) can all result in higher MOI at impact.
There are a number of variations of the square design or even direct knock offs of it. Just about every driver introduced this year (2007) boasted a high MOI, and from what I’ve seen and heard there are a few shared variables:
1. High MOI drivers don’t add distance and are not especially workable.
2. They tend to make a lot of noise at impact. (A handful of customers have returned their FTi, Cobra LD or Sumo2 because they couldn’t stand the sound of them).
3. The ball is launched faster off the high MOI driver face, which frequently results in a higher ball flight than expected.
