MOI is simply a measurement of a putter head’s weight properties. A putter with high MOI is resistant to twisting and turning upon impact.
Consequently, if you errantly strike the ball away from the center of the putter face—say, toward the toe or heel—a putter with high MOI will better resist twisting off target. The result is enhanced forgiveness and accuracy on miss-hits.
You can easily get a sense of MOI by pinching the shafts of different putters and twirling them in your fingers. The difference is usually physically discernible, with high MOI putters giving added resistance.
MOI is increased when weight is moved away from the putter head’s center of gravity during the design process. Consequently, the pursuit of extra-high MOI can result in some unique putter shapes. The Cobra Optica, TaylorMade Spider and Nike IC 2020 (pictured here) are some exotic examples of putters with high MOI.
So should MOI be your first priority when buying a putter? No. The overall fit and feel of your putter should be the priority, because the better the fit and feel, the less miss-hits you will have in the first place.
However, if you can find a putter that fits your game and has high MOI, you will enjoy added insurance on less-than-perfect strokes.
P.S. Portions of this piece are excerpted from PutterZone.com’s Ultimate Putter Buyer’s Guide ($5), a groundbreaking e-booklet designed to empower you with crucial fitting information before you spend big bucks on a putter. Click here for more information.