Putter Playability
by: Ralph Maltby - Founder of The GolfWorks
If everyone struck a putt on the horizontal center of gravity location of the putter face, there would be no need for a Putter Playability Factor. The actual ball impact point on the putter face is both a function of the golfer’s ability and how long the putt is. It is a fact that better players usually hit the ball close to the putter head’s center of gravity while most average golfers do so inconsistently. And, for most players, the longer the putt, the harder it is to hit the actual putter head center of gravity.
A term that has been commonly used over the years to describe a club’s performance is “sweet spot.” I think by now all golfers realize that the size of this so-called sweet spot varies from club to club. There are a number of factors that help to determine a putter head’s sweet spot. However, there is one factor that has the most influence, and that is its Moment of Inertia (MOI). MOI is simply defined as a measurement of the putter head’s resistance to twist or turn when acted on by force away from the center of gravity. An example would be a putt struck off-center or more correctly a putt not struck on the putter head’s horizontal center of gravity. This will make the putter head twist or turn at impact. The farther off-center the hit, the more twisting. If the hit occurs exactly at the center of gravity, then no twisting occurs. The more twist that occurs the more the putt will be offline. This brings us back to “sweet spot.” The higher the MOI, the larger the sweet spot and conversely the lower the MOI the smaller the sweet spot. Obviously, it would be very important for a player who has trouble hitting the putt consistently near the center of gravity to use a very high MOI putter head. Common features of high MOI putter heads are head shapes with more material in the heel and toe areas, longer putter head lengths, and heavy weights such as brass, lead or tungsten added in the heel and toe areas.
The Maltby Playability Factor (MPF) places all putter heads in one of six different categories. These are the same categories that are used in the iron head MPF but putter heads are calculated differently. Since the MOI is mainly responsible for the size of a putter’s sweet spot, it is used exclusively for determining the putter head MPF. The MOI is taken accurately and measured in inch-ounces2.
Putter Playability based on Moment of Inertia was thoroughly tested and proven using robotic putting machines, ultra high-speed photography and player testing. Hundreds of GolfWorks School students visited the Golf Club Design studio throughout the year and saw these capabilities with live robotic demonstrations. Every school student came away with a much better understanding of how putters work, how to fit putters better and to say the very least, they were all amazed.
Sometimes it’s not you … it’s the equipment!