Ralph did studies on this many years ago and the general rule of thumb is that for every 1/2″ you mis hit a shot off where the center of gravity is you loose 5% of your distance on irons and 7% on woods. I am sure that has changed some, especially on drivers since the biggest change in design has occurred in Drivers from, an MOI standpoint, over the last 30 years or so. There are more higher playability irons today, but it is not all irons like it is with basically all drivers. All premium drivers are 460 cc and have significantly higher MOI’s than drivers back when they were significantly smaller. Iron designs have not progressed that much, but designers that do understand how mass and dimensional characteristics of the iron design affect stability and forgiveness, and account for it in their design, generally have produced better designs. If an iron is just designed for a look and the key factors that make an iron stable are not considered, the design will not be as playable.
All that matters in how much distance is affected on off center hits is the stability of the iron. The more stable, the less affect on distance on off center hits. In our MPF ratings, which is in it’s simplest terms a measure of stability and forgiveness, you would expect the higher the MPF rating number the less distance lost on off center hits. It is that simple in irons. Those irons you test that you say are in the game improvement category, are they really? They may be, but just because a company says they are, or just because it is a cavity back, doesn’t automatically mean it is. Again, the ONLY thing that matters is the mass and dimensional characteristics of the design. That is why we believe the Maltby Playability Factor is such a great tool in determining how playable (stable and forgiving) any particular model of iron will be.
Britt Lindsey
Thanks for the overview Britt. Whether they are a good resource or not, when looking at CoolClubs’s plotting of robot testing for off-center strikes, the MPF don’t always match up to results. For example, I’m seeing Taylormade Qi, showing a massive front to back variation in both off strikes and more centered with a MPF of 876, while the P790 with a 697 MPF shows a much shorter front to back dispersion in both off center and more centralized strikes.
I realize these two clubs are different designs/technology and forged vs cast, but just trying to understand how Maltby clubs compare when I’m not exactly seeing MPF directly translate. As at least in this case with Taylormade, a lower MPF iron head is less punishing on mishits.