Equipment

TrackMan Club Head Speed Accuracy

If you have been to a fancy driving range, club fitter or watched The Golf Channel’s coverage of PGA Tour events lately, no doubt you have heard of the TrackMan. If you have not, it is a device that measures swing speed, ball speed, spin rates, carry distances…just about anything you could possibly want to know about your ball and where it is going…for something around 20 grand.

Here is a post apparently by someone working for the TrackMan company, on one of the major golf forums:

I just wanted to add our comments to this debate going on about Trackman and Smash Factors. First of all, both the ball speed and the club speed in all versions of TrackMan software are measured. However, in version 2.1 and earlier versions, we sometimes measured the club head speed closer to the heel resulting in a lower club head speed by up to 5-6 mph. This has a dramatic influence on the smash factor:

Let us assume the correct club head speed is 100 mph and ball speed is 148 mph (S.F. 1.48). If the club head speed is recorded erroneously as 94 mph this would produces a smash factor of 1.57! In order to prevent this phenomenon which almost solely happened on drivers, we have in version 3.0 and 3.1 a mechanism gets rid of club head speed readings that have too high smash factors. In version 3.0 this “soft limit” is 1.48 where it is 1.50 for version 3.1. The absolute upper limit for smash factor is 1+COR, but this would require a very heavy club head (there exist no upper limit) compared to the ball weight (there exist no lower limit) and the impact should be a centre impact that puts no spin on the ball. For realistic club head weight of 215 g and a ball weight of 45.9 g for a low spin rate of 2000 rpm the upper limit for the smash factor will theoretically be (1+COR)*0.805, which for COR of 0.83 gives 1.474.

So when I say a “legal” driver and ball can not exceed 1.50 this is not 100% true, but for all the drivers and balls I know about it will practically be impossible to exceed 1.50 for smash factor.

Remember also in all this that the accuracy of the club head speed when using a TrackMan is +-1 mph. At 100 mph club head speed this could make a smash factor appear as anything between 1.465 to 1.495. Smash factor is a very sensitive ratio.

Furthermore, recall that the club head speed measured by the TrackMan is referred to the centre of the club face, which is not necessarily where the ball is impacted. If you move 10 mm towards the toe the club head speed will typically be 1.4% higher. This can also skew the smash factor a small amount.

In our next newsletter (approximately 2 months from now) we will be discussing the smash factor in more details, since this has really made people talk. If you wish to receive this newsletter, please go to our website to sign up for it.

Interesting information here:

• Realistic Max Smash Factor: 1.474
• Claimed TrackMan Club Head Speed Accuracy: +-1 mph

So this brings me to some other information I saw. Callaway Golf has an interesting piece on fitting Ernie Els with the FT-i driver using the TrackMan equipment (Callaway seems to be in the middle of redoing their website design, so sorry if that link is broken).

Here is a little screen shot from the video at one point:

So what is showing on the screen here:

The ball speed seems remarkably consistent for an inconsistent smash factor. If one calculates the club head speed based off the smash factors (BS/SF=CHS):

That is a pretty large gap in club head speed. 134->116 = a 15% difference. Now, I know I am quite capable of making one swing at 115 and the next swing at 100. However, this is Ernie Els. If anyone has a tempo one could set their watch to, it is him. The TrackMan post claims that it can accurately measure club head speed by +/- 1mph. It also notes that hits toward the toe can show club head speeds of up to 1.4% higher. We’ll we’re talking 15% higher here. Given that the Ball Speeds are almost identical on these three reported swings, I would have to assume the swings were somewhat similar? It would be quite a coincidence if one swung at 123…116…and 134…and all three hits came out nearly the same. Am I missing something here? This is by no means a scientific study on my part, I just noticed these things and was curious.

In the end, when it comes to fitting the club, I am sure little matters other than the spin rate, launch angle and ultimately the distance. However, I am sure it would be nice to know your real smash factor. Specifically to know how efficiently are you transferring your energy to the ball on mis-hits. If I hit it on the toe, did my smash factor drop to 1.1? One can do this test with an Iron Byron. Setting the machine to swing at a fixed swing speed, and to make impact at a specific location on the head. Unfortunately, I can’t just set my swing speed to 115 and auto repeat on the toe. So for me, I would need more accurate data to tell me how a particular club is performing on my poor swings. If I knew the club head speed readings were accurate, the ball speed reading was accurate, then I could look at the numbers, look at some impact tape, and really know if my 265 yard carry was due to the technology built into the driver, or was just a variation in my delivery of the club to the ball.

If you find this topic interesting, Sean Cassidy started up a new blog, Swing Speed Golf, targeting this specific area. Check it out, he already has some great posts on the subject.

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