Being on a search for new irons that would propel my game to the next level, along with being a bit of a math nerd, I was lead to Mr. Maltby’s iron rating system: The Maltby Playability Factor (MPF). I was intrigued. How could you not want to look at a true and unbiased breakdown of how easy to hit, playable as Maltby calls it, golf irons really are? Numbers derived from physics and trigonometry computations and not data provided by the iron maker themselves — Granted Maltby’s irons fared well, but they don’t interest me. I was analyzing Ping vs Taylormade vs Cobra vs Mizuno and so on.
Seeing the topic of Maltby’s work being scrutinized and ripped apart on forums built more curiosity. I wondered how could it be that Callaway’s 2016 Apex, a sought after and popular iron, could be classified as, “difficult to play, 0-5 handicap only. No game improvement features?” (https://www.golfworks.com/iron-head-mpf-ratings/a/870/) Man, I just hit those at Golf Galaxy and I thought they were sweet! Why is the MPF so against them.
After analyzing Maltby’s data tonight, and what a wild night it was crunching numbers in hopes of getting that magical iron set that allows me to break 80 more than once or twice a summer,I discovered Maltby’s error.
First, we can all agree from the physics lesson we all seem to follow as golfers that:
1) Center of gravity low equals high launch.
2) Center of gravity deep in club face equals forgiveness and likely more spin (game improvement features)
3) Center of Gravity forward equals lower spin and less forgiveness (players club attributes)
Second, using this knowledge it would be obvious that Maltby’s ratings will award points (awarded for more “playability”) for clubs with a lower and deeper center of gravity – as well it should. Just like a Ping G series is easier to hit than an I series, the CG is placed low and back in G clubs for game improvement attributes. So that being said, players clubs with a more forward center of gravity wont score as well. ok we get it. But why are some better player’s clubs being ranked as unplayable?
The answer….a simple error on Maltby’s part…size of face on iron. Those players irons are more compact and have smaller heads than their game improvement brothers. Why does this matter??
Look here https://ralphmaltby.com/method-of-determining-mpf/
Maltby’s mistake is that he is measuring the distance up the clubface where the center of gravity is located in inches from the bottom of the club face. So The callaway apex 2016, and its smaller head, comes in with a CG .871 inches up the face from the leading edge on bottom. The 2017 Big Bertha OS measures .890 inches from bottom edge to CG location. Pretty similar right? But wait! the Bertha OS is an Over-Sized club head. Hence the OS in its name. The Apex is a compact player’s iron.
So .890 inches up the larger Bertha OS face might only be 40% of the way to the top of the clubface — while that same .890 inches may come up 50% of the way from bottom-to-top on the smaller Apex head.
Get it? Did I explain this well enough i wonder? Maltby should measure CG location as a PERCENTAGE of the distance from bottom of clubface to top, and NOT MEASURE in INCHES!! He is not accounting for different sized clubheads!! Smaller, player irons – and their smaller heads – are losing MPF points because of an erroneous CG location being very high on the face. If I made a iron head that was identical in proportion to the 2016 Apex but 4 times the height and 4 times the depth of the 2016 Apex, an iron head the size of a frying pan, it would get exactly 4 times the points under Maltby’s calculation – because its not measuring the CG location in terms of percentages or fractions from bottom of clubface to CG location.