Are there any scientific studies to show a how higher MPF ratings in clubs affect actual performance in terms of distance and dispersion? It would be nice to be able to convince skeptics of the value of higher MPF numbers.
Plenty of data that supports that the best selling clubs and the longest lasting in the market place at any time since Ralph started the study and wrote the book, and even before he wrote the book, had the highest MPF. My suggestion is to read the book to understand what the MPF tells us about the design of irons and how it does effect the stability and ultimately the playability of the any particular design. Ralph also is very clear about what it doesn’t do. The original 2004 MPF on irons specific book is the original book on the subject and it was rolled into “The Complete Book of Golf Club Fitting and Performance – The Principles, Procedures and Playability Factors”, which discussed more topics related. What happens to an object, in this case an iron head, how it moves when it is in motion, is totally dependent on it’s mass and dimensional characteristics and where the actual cg is located vertically, rearwardly and horizontally. Depending on these mass and dimensional characteristics of the design, we know what will happen when it is in motion and what it will do at impact. If the ball is struck right on the cg every time, MPF doesn’t really matter. However, there are two points to make here 1. Very few designs I have measured have the cg perfectly in the center of the face. The last I checked, I think we all aspire to hit it in the center, so if the cg is not there … and 2. The greater the horizontal cg, the more rearward the cg and the lower the vertical cg, in an iron head, the more stable it is in motion and on off center hits. So, if you hit it in the center of the face every time and the cg is actually in the center of the face, again MPF doesn’t matter. Play whatever design you want. If you don’t, lower rated MPF designs will not perform as well and if thousands of shots were tracked with thousands of players, over time we are very confident we know what the results will be. In a more extreme way, modern day drivers simply prove the point. Do you think todays drivers are more forgiving and more stable today than the first metal woods, or wood woods? Of course they are. Why do you think that is? Size and what that size did to where the cg is located and how that effects the stability of the mass, or the driver head. Head weights of drivers today and drivers from 50 years ago are still 195-203g basically. So the weight hasn’t changed. Same goes for irons, generally and within a few grams. So basically the MPF simply tells us how stable the mass is in motion and at impact and the more stable it is, the better the performance. Iron heads do not all have to be massive to have a high MPF and I have measured some that were big and had horrible MPF’s because they did not pay attention to where the CG was. Just because it’s a “cavity back” or an “oversize design” does not automatically mean higher playability. There are certain things we have learned and apply to our designs to insure they have the highest playability possible for the category of iron we are designing for and for the look we want. Technology and manufacturing technology, and materials allow us to make some nice traditional looking irons with high playability. Blade lengths may be slightly longer and hosels may be slightly shorter, but still look good and allows us to put the cg in the best place possible. If you design to a look alone, and don’t pay attention where the cg is, generally the MPF is lower. We see this specifically in “players” designs where companies continue to make blade lengths too short and hosels too long and soles too narrow because some tour pro likes that look. That’s fine for the tour pro if he can hit it on the cg every time, but that slight miss he may have from time to time will not perform as well as a well designed players design that is more stable. I could go on and on, but Ralph’s book explains it well and validates it. If you don’t have it, you should get a copy and decide for yourself. It is based on the very simple and immutable facts of the mass and dimensional characteristics of an object, in this case, an iron head.
Hope this helps.
Britt Lindsey
I have just read this thread again and truly appreciate Britt for his expertise and his willingness to share so generously with us all.
His point about reading Ralph’s books is to be taken seriously. I have read them and have become a better club fitter and club repair man. (Of course, I must add that Jim Yachinich and his classes were fabulous and very helpful. Jim is also a wealth of knowledge!)
Thank you, Britt. I totally get what you’re saying. Actually, I have Ralph’s books and am quite familiar with them and what he presents there. While taking classes there at Golfworks you even took us to visit his home and shop!
I hope your answer helps many others better understand MPF, but getting his books should help them the most! Thank you again!