Playability of Putters
If everyone struck a putt on the horizontal center of gravity location of the putter face there would be no need for putter head playability factor. We all know this is not the case.
Playability of Putters
The actual ball impact point on the putter face is both a function of the golfers’ ability and how long the putt is. It is a fact that better players usually hit the ball more consistently close to the center of gravity and for most all players, the longer the putt, the harder it is to hit the actual putter face center of gravity.
The “Sweet Spot”
A term that has been commonly used over the years is “sweet spot.” I think by now all golfers realize that the size of this so-called sweet spot varies from club to club, whether we’re talking about putters, woods or irons.
There are a number of factors that help to determine a putter head’s sweet spot. However, there is one very significant factor that determines this. That factor is the putter head’s Moment of Inertia (MOI).
Moment of Inertia (MOI)
MOI is simply defined as a measurement of the putter heads resistance to twist or turn when acted on by an outside force. 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 location.
This will make the putter head twist or turn at impact. The farther off-center the hit, the more twisting that occurs. If the hit occurs on the center of the face, then no twisting occurs and MOI has little meaning. The more twist that occurs the more the putt will usually be off the intended line.
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 the putter face 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 toe to heel and heavy weights such as brass, lead or tungsten added in the heel and toe areas.
Maltby Playability Factor (MPF)
The Maltby Playability Factor (MPF) places putter heads in different categories. These are the similar categories that are used in 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 the predominate mass dimension used for determining the putter heads MPF.
The MOI is taken accurately and measured in inch-ounces squared or grams per centimeter squared. This MOI number is used, along with other weight distribution data to calculate the MPF category the putter head fits into.
Putter head playability based on Moment of Inertia and other mass and dimension properties was thoroughly tested and proven using actual robotic putting machines and ultra high speed photography.
Hundreds of GolfWorks School students visited the Golf Club Design studio throughout the year and were actually shown these capabilities with live 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 at the differences in putter playability from the various designs of putters that exist.
For much more information and a complete understanding of putter playability, Section 11 of my book, “Golf Club Fitting and Performance” details Putter Fitting, Performance and Playability Factors.
I highly encourage those who want to have a complete understanding of the playability of putters to read this section of the book. You will come away knowing the important factors to consider when deciding on what type of putter you should be using and what steps you need to take to insure you have the best fit and style putter for your game.