INTRODUCTION
More and more customers today are being custom fit for golf clubs. With the use of TrackMan and custom fitting tools we have the ability to get customers playing better golf with properly fit equipment. Almost all fitting facilities use a hitting mat of some sort for their fittings.
Without the ability to grow and maintain a grass hitting surface in our fitting center the next best alternative is a high quality hitting mat such as the Country Club Elite.
Our goal in every fitting is to put properly fit clubs in the hands of each and every customer. A properly fit club should perform on the golf course just as well as it does while in our fitting center, The Launch Pad. Therefore we examined the effect that different hitting surfaces could have on ball flight characteristics and as a result performance.
PROCESS
By using TrackMan III we have the ability to capture the data necessary to examine the differences between hitting golf balls off mats vs. grass.
In order to control as many variables as possible we utilized TrackMan III’s normalize function. Normalization allows us to adjust weather conditions to eliminate the effects weather may have on our test. For example, the ability to set temperature, elevation for our location, and take wind out of the equation.
The club used for the testing was a Titleist 712 AP2 7 iron with a Dynamic Gold S300 shaft. Length, loft and lie were standard on the 7 iron.
The golf ball used for the testing was the 2013 Taylormade Lethal. The mat hitting surface used is the Real Feel Country Club Elite.
The grass we hit from is a combination of Bent grass and Rye. All shots were hit off of a dry surface and after each shot, the club head was wiped clean of any debris to ensure the most consistency possible in the data collection.
Our largest variable would be our human element. Because of this we selected a low handicap (+2). He competes in many amateur events in the state. We chose this player because his club data would have a high consistency.
It is still going to be player dependent and come down to individual swing characteristics as to how much influence the different surfaces will have.
As a note this test was done using one player in a single scenario. Different results could come from different surfaces and swing type.
RESULTS
Below is the data that we have collected from our test. There are a total of 10 shots from each surface.
In Figure 1 we have 4 data points we have collected, two of which was our focus Launch Angle and Spin Rate. Our goal was to find out any parameters that showed significant change which these two did.
| NORMALIZED | Ball Speed (mph) | Launch Ang. (deg) | Spin Rate (rpm) | Carry (yds) | Height (ft) |
| 7 Iron Grass | 129.3 | 14.5 | 7613 | 179.7 | 95.8 |
| 7 Iron Mat | 128.5 | 17.2 | 5685 | 186.9 | 107.1 |
| Variability | 0.8 | -2.7 | 1928 | -7.2 | -11.3 |
Figure 1
| NORMALIZED | Club Speed (mph) | Smash Factor | Land Ang. (deg) | Spin Axis (deg) | Side (ft) | Attack Ang. (deg) | Club Path (deg) | Face Ang. (deg) | Face To Path (deg) | Dyn. Loft (deg) | Launch Dir. (deg) | Spin Loft (deg) |
| 7 Iron Grass | 93.7 | 1.38 | 47.1 | -0.9 | 13.5R | -4.2 | 1.7 | 2 | 0.4 | 20.4 | 1.9 | 24.7 |
| 7 Iron Mat | 91.7 | 1.4 | 48.3 | 0.1 | 26.6R | -4 | 2.6 | 2.7 | 0.1 | 21.7 | 2.7 | 25.7 |
| Variability | 2 | -0.02 | -1.2 | -1 | -13.1R | -0.2 | -0.9 | -0.7 | 0.3 | -1.3 | -0.8 | -1 |
Figure 2
Figure 2 is showing club data between the two surfaces. As you can see from the chart there is minimal change in Club Data, we are safe to assume that the major variances in Launch Angle and Spin Rate were affected solely by the surface.
Launch Angle is a measured parameter just after impact in relation to the horizon. Launch Angle is affected by 3 major contributors, Dynamic Loft, Attack Angle and Ball Type.
Ball Type was kept consistent using Taylormade Lethal golf balls on each surface. Dynamic Loft and Attack Angle which comprises Spin Loft (Dynamic Loft minus Attack Angle) showed a 1* lower Spin Loft from mat to grass, concluding that these two parameters are within an acceptable variance.
Seeing a 2.7* lower launch off of grass did grab our attention. For instance during an iron fitting we would like to see 2* Launch Angle change between irons, i.e. from 6 to 7 iron. So if we do not know this information as to how grass will affect the golf ball, a perfectly fit 6 iron off of the mat will launch like a 5 iron on grass. This type of change can result in properly fit golf equipment off a mat, but will not achieve the desired Launch Angle when hit off grass.
Spin Rate is the total amount of spin RPM’s (Revolutions per Minute) measured just after impact. Spin Rate has 4 contributors, Spin Loft, Club Speed, Impact Location and Friction. With Spin Loft, Club Speed and Impact Location showing little variance we are left with few explanations. Our Spin Rate showed a significant increase once hit off of grass compared to the mat of 1928 RPM’s. As a general rule the change per iron is about a 1000 RPM’s. So the 6 iron that you got fit for off of grass is now spinning like an 8 iron.
CONCLUSION
To be an effective club fitter, one needs to recognize the relationship between hitting surfaces and realize that there could be a difference in TrackMan data when hitting off of mats vs. grass.
We have been excited that we did this testing early on in our fitting program, so we can better understand what types of launch conditions our players will see on a golf course where it actually matters.
Our test that we performed is not a tell all template. There are various swing types that could influence numbers differently. But with the understanding that the hitting surface is to be considered a factor when fitting this will allow for a better fit. With almost all fitting centers using some sort of mat for fittings we recommend that TrackMan fitting facilities do similar testing for their consumers benefit.
Table 1. Test Results
Image 1. TrackMan Performance Studio Screenshot
Image 2. Top/Side View – TrackMan Performance Studio
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