Independent testing at the Quintic Ball Lab USA in Massachusetts confirmed the importance of MOI, moment of inertia, resistance to twisting. Quintic Ball Roll Lab USA in a second phase of testing explored the impact of the utilization of the extreme weight range allowed by the Cure RX Series putter. In this human (no more robots) testing we discovered the surprising benefit of weight optimization fitting.
The alpha test was with a 16 handicap golfer; an average putter for his handicap with a 2.9o face angle variation range in his baseline putter test. 9 Cure RX Series putter configurations were tested. Face angle variation range decreased (improved) in the first 5 tests; and then failed to improve more in the last 4 tests. The putters in tests 1-5 “felt” good to the player; the putters in tests 6-9 “felt” too heavy to the player. An OPTIMUM WEIGHT was discovered at 409 grams for this player.
The alpha test discovered an optimum weight outside the industry expectation (as indicated by the average weight of available putters) of between 345g and 355g. Improvement in a number of putter launch metrics was noted, including importantly: putter speed variation range, launch angle range, and zero skid range.
The beta test was with a 6 handicap golfer; a relatively poor putter for his handicap with a 2.1o face angle variation range in his baseline putter test. 9 Cure RX Series putter configurations were tested. Face angle variation range decreased (improved) in the first 2 tests; and then failed to improve more in the last 4 tests. The putters in tests 1-4 “felt” good to the player; the putters in tests 5-9 “felt” too heavy to the player. An OPTIMUM WEIGHT was discovered at 395 grams for this player.
The optimum weight for face angle variation range and putter speed variation range coincided at the same weights; with the same pattern: improvement up to the optimum weight and then no further improvement.
Subsequent tests have been done with players of all skill levels including PGA Tour players, PGA Tour Champions players, LPGA Tour players, web.com and mini Tour players, International Tour players and amateurs from +4 handicap to -32 handicap. The results persistently confirm an optimum weight for players of all skill levels a putter weight heavier than generally available in the market.
The results are GAME CHANGING!
Average players can improve their putting to tour caliber without a putting lesson. Simply put a weight optimized, MOI maximized putter in their hands and their putting launch monitor metrics improve, a lot!
This is scientific proof that each player has an optimum weight, individually determinable.
The formula for MOI, moment of inertia, is mass (g) times distance (cm) squared. So you can increase MOI a little by increasing the mass; but a lot by increasing the distance of the mass from the axis of rotation. MOI divided by mass is radius of gyration squared (k2). This is a very simple calculation; and allows a direct measure of the effectiveness of the mass distribution in generating MOI.
The Scottsdale anser was an important improvement over the old blades; 19% more k2 (9.43/7.92) than the old blade. The Newport 2 was another important improvement; 30% more k2 (12.34/9.43) than the original anser style blade. But there is a limit to the improvement possible in the traditional geometry using the heavy steel base material. Steel weighs about 7.92 g/cm3
The CURE TX1 develops 40% more k2 (17.41/12.34) than the Newport 2 by using lightweight aircraft grade aluminum as a base material. The aluminum weighs only 2.72 g/cm3 (and feels great!). By using tungsten weights in the toe and heel, the TX1 develops the MOI of a large high mallet in a blade.
The CURE RX5 uses the same aircraft grade aluminum but in a 6” wide putter; developing levels of MOI, STABILITY and forgiveness never before seen.
The modern putter evolved from very light wooden shafted wooden head putters with 10 or more degrees of loft (sometimes a lot more than 10 degrees). Many golfers would carry two “putters”; one with about 10 degrees of loft for putting very near the hole itself; and a second, with 12 to 15 degrees of loft, for putting from distances of 30, 50 or even 80 yards from the hole.
Greens in the 19th century were cut with scythes to a height that would be similar to our fairways and tees today. The invention of the lawn mower in 1830 by Edwin Budding in England enabled important changes in golf course maintenance.
Historical Green Speeds in the USA
By the early 20th century, putting greens were being mowed to 3/8” in height.
By the end of the roaring 20’s, green mowers had developed into specialized equipment, and mowing heights were a little tighter. Putter loft began to decrease; but the Calamity Jane putter used by Bobby Jones to win his Grand Slam in 1930 still had 8 degrees of loft. Between 1930 and 1980, greens steadily improved; but the “fast” greens of today still did not exist.
The Stimpmeter, invented by Eddie Stimpson, was used by the USGA in 1977 to measure 581 courses nationwide to benchmark the speed of American greens. Here is a sampling of what was found:
These were America’s finest courses; the averages courses and “muni’s” were more typically in the range of 4 to 6 feet.
While the loft of putters began to decrease as the mowing height on the greens was reduced and green speeds increased, the loft of standard putters remained quite high.
Green Speed, Cut Height and Putter Weight Evolution
The steady decrease in mowing height and loft, and the increase in green speed and putter weight is
evident in the table below:
The Myth of the Nested Ball
It has for many years been “common knowledge” that some loft is required on a putter to lift the ball out of the depression in the grass that it was sitting in. This was likely true for Bobby Jones, Ben Hogan and Arnold Palmer; but is no longer true today.
A famous putter designer in his current putter fitting guide states that his “Putter Studio research shows that a ball pushes down slightly into the grass on a green, and that 3.5o loft is needed to lift the ball up and on to the surface for a smooth roll.” He is not alone. This statement could have been made by any of hundreds of top teachers.
But the ball is no longer sitting in a deep depression in the grass on a putting green today.
In addition to the evidence from historical developments on the putting green, new research is pointing toward lower loft.
The growing use of launch monitor metrics has confirmed that less loft, higher weight and higher MOI are more consistent on today’s faster greens.
The growing use of launch monitor metrics has revolutionized club fitting. Woods & irons today are routinely fit on the basis of launch monitor metrics: launch angle and direction, spin rate, smash factor, carry distance and club twist at impact.
The use of putting launch monitors is not yet as widespread, but is growing. The single most important putter launch monitor metric is face angle variation. The face can be closed, square or open at impact. In the example below the face angle variation range is 2.0o (1.0o closed to 1.0o open). Even in the “stopped- frame” view below, one degree is not easy to see. In real time it very hard to see.
Face angle is the overwhelming determiner of the direction of the ball. Stroke path is much less important.
Face angle variation can be reduced by increasing the MOI, moment of inertia, of your putter. Putting launch monitor testing has confirmed that high MOI putters can reduce face angle variation range by 50%, or more! While this fact is not yet widely known, the growing use of putting launch monitors will confirm this game changing fact.
Increasing the MOI, moment of inertia, of your putter makes it more STABLE; and this added STABILITY is reflected in decreased face angle variation. This is physics; and this is a game changer!
Independent testing at the Quintic Ball Lab USA in Massachusetts confirmed the importance of MOI, moment of inertia, resistance to twisting. STABILITY, forgiveness and MOI are clearly related.
The results shown below were obtained on a state-of-the-art robot. An traditional anser style putter was tested against a high MOI Cure RX Series putter: first, with a center hit; and then second, with a 1⁄2” off- center hit.
Figure 1 (above) shows the comparison of the center hit and off-center lab test results. Both the traditional anser style putter (top) and the high MOI Cure RX Series putter (bottom) performed well on the center hit (left side), with 0.0o twist and a 1.70 impact ratio.
The off-center hit (right side of figure 1 above) exposed the weakness of the traditional blade putter and the strength of the high MOI putter. The anser style putter twisted 6 times as much as the high MOI putter at impact. SIX TIMES as much; 1.00o vs 0.15o of twist at impact. Putter twist at impact will send the ball off line. The actual directional result is quite complicated, but twisting is not helpful.
Impact Ratio is the ball speed divided by the putter speed at impact. The ball in this case was going 1.70 times as fast as the putter head. 1.70 is a relatively common impact ratio for putters. You may be more familiar with the concept of Smash Factor with your driver or irons. Smash Factor and Impact Ratio are EXACTLY the same number (ball speed divided by club speed). It is not helpful that the industry is using two terms for exactly the same thing. Both could be called Impact Ratio, but that is not going to happen. Smashing, think KABOOM!, works with drives; putting is more delicate and precise, so get used to impact ratio on the green.
The off-center impact resulted in a reduction of impact ratio. Less of the forward energy of the putter head is transferred to the ball. The anser style putter deteriorated from 1.70 to 1.52 on the off-center hit, enough to cause the putt to come up over 3 FEET short. The high MOI putter only deteriorated from 1.70 to 1.69, almost nothing at all, causing the putt to come up only about 2 INCHES shorter. So a high MOI putter improves BOTH the DIRECTION and DISTANCE resulting from an off-center hit.
Increased MOI, increased resistance to twisting, increased STABILITY, increased forgiveness, improve putting performance. This is physics. Higher MOI produces measurable improvement and forgiveness.
Did you know that STABILITY and MOI are directly related in your putting stroke? Let us explain.
MOI, moment of inertia, is resistance to twisting. It doesn’t matter if the the twisting (red arrows in the illustration below) is from an off-center hit, subtle unwanted face angle change from your hands and wrists, or even the yips.
How would a high MOI putter help? A high MOI putter resists and reduces ALL twisting. A high MOI putter is more STABLE than a low MOI putter; period.
STABILITY on an off-center hit is experienced as FORGIVENESS. A high MOI putter will twist less, and a low MOI putter will twist more due to an off center hit. Putter twist at impact will send the ball off line. The actual directional result is quite complicated, but twisting is not helpful. In addition to twisting off line, an off-center impact will result in a reduction of impact ratio. Less of the forward energy of the putter head is transferred to the ball; and the putt will not go as far as you intended.
So, a high MOI putter improves BOTH the DIRECTION and DISTANCE resulting from an off-center hit. Forgiveness on an off-center hit is important and beneficial.
But STABILITY in the stroke itself is even more important. MOI also resists the twisting (red arrows in the illustration above) from unwanted face angle change from your hands and wrists. A high MOI putter is more STABLE; and resists twisting away from square to the arc; it imposes STABILITY on the stroke itself. This is not just a theoretical improvement; it is real, and the improvement is substantial. Putter launch monitor testing of high MOI putters confirm that face angle variation can be reduced by more than 50% just by increasing the MOI of your putter. Read the last sentence again!
Every putter manufacturer is talking about stability. Everyone seems to know that STABILITY is a good thing in a putter. Obviously, no one wants an unstable putter. Manufacturers claim improved, increased, or enhanced STABILITY from combinations of materials as if it is magically produced. There is no STABILITY MAGIC. Putter stability can be measured and compared. Quite simply. The measure of STABILITY is MOI (moment of inertia), or resistance to twisting.
As explained, MOI and STABILITY are directly related. And if you don’t know the MOI of your putter, you should. A high MOI putter is more STABLE; period.
Jerry Kelly’s fantastic 2018 season continued Sunday with a 2nd Place finish at the American Family Insurance Championship at University Ridge Golf Club. Using his Cure Putter, Jerry’s 2nd Place finish helped him regain the Top Spot on the Charles Schwab Cup List, a place he held earlier in the season. Jerry finished only one shot back of winner Scott McCarron. The 2018 season has been full of great highlights with Jerry winning the Mitsubishi Electric Championship in Hawaii coming on the heels of winning Rookie of the Year honors for the PGA Tour Champions. To go along with that, Jerry has eight Top-10 finishes (two Runner-up’s & two Top-5’s) in the twelve events that he has played and he leads the PGA Tour Champions in scoring average.
“We’re thrilled to have Jerry Kelly rolling our CX1 putter and happy to see him playing so well” said Jim McCarthy, CEO of Cure Putters. “Jerry’s a very talented player and a great ambassador for our brand. We’re very proud to be associated with him and wish him continued success down the stretch as he goes after the Schwab Cup Championship!”