I had some questions this week that I thought I’d answer. Next week we can get back to the boring specs.

First question. YES!! I write these every week. This is not some company scripted deal that they send me and I copy and paste. I write what comes to mind or what people ask me about.

Second Question. I started fitting clubs in the early 90’s, and the first club company I worked for was Cobra in 1994. I became a Certified Club fitter for Cobra in 1994. In 1995 I became a Master Club fitter for Cobra, and have since become a Master fitter for Mizuno, Adams, Cleveland and Callaway. So, I have been fitting clubs for 28 years. 

Third Question. Someone asked me about the COR of the new driver. This is a 2 part answer. COR stands for Coefficient of Restitution, which means spring like effect for club heads. As it relates to the new Paradym driver, it has not made it to the USGA Conforming list (our choice), but we are fully confident that it will. It is scheduled to hit the USGA list on 1/2/23. 

How do they actually test clubs for Spring like effect? It has evolved over the years. Partly to make it more transportable, and partly to make it more relative to what the test is actually trying to test. 

The COR Test is out dated, but it is still used in certain instances. If you remember, the spec was .830. If a driver tested higher than .830 it was deemed non-conforming. What exactly is .830? Here ‘s the test. A club head is removed from a shaft and mounted to a rod in in a chamber. A ball is fired at the center of the club face from a ball cannon at 100 MPH. If it rebounds off the face at more than 83 MPH, the head is deemed non- conforming. .830 = 83% of the original input. It’s a simple test, but awkward to replicate. Certainly not convenient to replicate at a tour site. It is also not foolproof. A face could be conforming at 100 mph, but not conforming at 120 mph. It was eventually realized that this, along with testing spring like effect via ball speed was testing ball speed – not spring like effect. So, the USGA devised a new test called the CT test (Characteristic Time) that can be used instead of the COR Test.

The CT Test is measuring how long a body (in this case a steel ball with a microscopic timer in it) is in contact with another body. Essentially, if the time is higher, the ball is in contact with the face longer and the premise is that the face is cupping and springing the ball off the face. It’s measured in microseconds. 239 microseconds is the limit, but a tolerance of 18 microseconds is permissible (meaning 257 is the actual limit). In a nutshell, .830 = 239 microseconds. This test is very compact and is very usable at an event, and it has become the test of choice.

There are a couple of things to note here. First, the tolerance of +18 microseconds was established to account for and allow for imperfections in manufacturing over the course of a long run of production pieces. The truth here is that now, every company has manufacturing tolerances and methods that are so good and so consistent that they are able to manufacture clubs above the 239 limit but under the 257 hard ceiling, and still have every piece still conform. Second, the CT Test doesn’t actually measure ball speed – it measures the equivalent spec of the forces that measure how spring like a face is. IF a manufacturer can figure out a way to to keep CT at 239 (257), but make a head transfer energy more efficiently , BALL SPEED can be increased WITHOUT increasing spring like effect. Jailbreak is the technology that does just that. Third, ALL clubs that are 25* or stronger are tested for CT. This includes fw woods, hybrids and irons. Quite often I hear that a smash factor of 1.50 deems a club conforming or not. While this is a decent guideline, it is by no means a test or a definitive ceiling. As a refresher, Smash factor is Ball Speed divided by club head speed. 100mph in, 150mph out is a 1.50 smash factor. I will routinely see smash factors above 1.50 – even with a FW Wood.

One final note about Smash factor. 1.50 is not for every club. As loft increases, smash factor decreases. The ideal smash for a 7 iron is 1.35, a 3 wood is 1.43, and a wedge is close to 1.00. Certain impact conditions can influence smash factor positively or negatively, that’s why this isn’t a definitive test. CT and COR both eliminate the golf swing from the equation. A flat swing with a high positive attack angle and center strike on a driver will have a high likelihood of a smash factor above 1.50. Conversely, an over the top swing with a negative attack angle will reduce efficiency and make smash factor lower that optimal, even if the strike is on the center of the face. Neither of these situations have anything to do with the spring like effect on the club head.

Here’s your takeaway. COR is an outdated test that is not used very much any more. CT Test is the new test and it tests every club stronger than 25*. SMASH Factor has nothing to do with Spring like effect test because the golf swing is part of the equation. Lastly, if a manufacturer can maintain an acceptable level of spring like effect in the face, but make a more efficient body that transfers more energy from the head to the ball, that is a legal golf club. Jailbreak is the first (and best) technology to allow this to happen. 

I hope this helps you. If you can understand HOW clubs work and what makes a club legal or not, it will help you be a better fitter. It could help you be a better instructor too. If you’re working with a student and thinking 1.5 smash with a driver is the ultimate, you may not be correct. The student may actually have a ceiling higher than that. Or, a student may have certain swing mechanics that may limit the ceiling of the Smash Factor he can achieve. Trying to chase a 1.50 smash with a negative attack angle will prove futile. Loft influences smash too – it will be easier to get a 1.5 smash with an 8* driver vs. a 10.5* driver (not that the 8* is the right choice, just something to keep in mind). 

Happy Fitting!!