(Ed. Note) In 2013 Don Irving of Artisan Golf achieved the rare designation of TrackMan Master after submitting a thesis paper on the results of a study he complete using TrackMan radar-based launch monitor technology for analysis. The subject was the effect of driver lengths and the performance of golfers. The following is a short summary of the lengthy and involved detailed study.
Before beginning the driver length study there were several questions the answers to which I hoped would become clear. The main questions were:
What is the effect of club length on club head speed?
What is the effect of club length on smash factor?
What is the effect of club length on distance?
What is the effect of club lengths on dispersion/accuracy?
The results of the study have led to the following conclusions:
Question 1 — What is the effect of club length on clubhead speed?
Using the 43” driver as a baseline there was an increase in clubhead speed as the lengths increased. The 44” driver, on average, across the four handicap groups showed an increase of 0.74 mph. The 45” driver showed an average increase of 2.09 mph and with the 46” driver there was an average increase of 3.5 mph.
Question 2 — What is the effect of club length on smash factor?
For this category, I looked at the results from a perspective of the shorter drivers (43/44”), average length drivers (45”) and long drivers (46”). The results showed with the shorter drivers 80-93.3% of participants had the best Smash Factor across the four handicap groups. With the average driver length of 45” it ranged from 5.6% to 20%. For the 46” driver it was zero per cent for all handicap groups, except the 16-23 groups, where it was 11.1%.
Without a doubt the majority of the test participants had better contact with shorter drivers.
Question 3 — What is the effect of club length on distance?
From the Summary Tables for each of the four categories, we can see that some handicap groups gained distance with a 46” driver over a 43” driver, while others lost distance. While some individual golfers had very significant gains with a longer driver there were others that had significant losses with a 46” driver versus a 43” driver. On average the highest net yardage gain among the four handicap groups was in the 16-23 handicap group with an increase of 8.85 yards for 55.6% of the group.
Among the four handicap groups, the most distance lost was an average of 13.95 yards. This too was in the 16-23 handicap group.
From the data collected, I would conclude that although longer drivers tend to produce more clubhead speed, they do not produce significantly longer drives.
Question 4 — What is the effect of club lengths on dispersion/accuracy?
To simplify the results, I grouped the driver lengths into short (43”/44”) average (45”) and long (46”).
Across the four handicap groups, the short drivers showed the best dispersion patterns. From 56-76% of participants had the best dispersion patterns with the short drivers, while 22-33% were best with a 45” driver and from 0-22% did best with a 46” driver.
The 0-15 handicap golfers (a combination of the 0-8 and 9-15 groups) had better dispersion patterns with the shorter drivers. In this range zero per cent did best with a 46” driver. In the 16-32 (a combination of the 16-23 and 24-32 groups) handicap range most did better with a short driver, but there were a few participants who did better with a 46” driver.
One piece of data that I found very interesting from the study was angle of attack. In all four handicap groups the ratio of golfers with a positive angle of attack to those with a negative angle of attack was quite consistent. It was roughly a 60/40 split. In the lower handicap group the negative angle of attack was quite low while higher handicappers showed steeper angles of attack. Along with the steeper angle of attack came higher spin rates that would not be considered optimum for the launch angle. I think those golfers looking to add a few yards to their drives would benefit from a more positive angle of attack but I suspect that this critical element is not being keyed in on because of a lack of awareness of this critical factor or the absence of the tools to measure it.
If we look at a combination of driver distance compared to dispersion, I would conclude that when fitting for driver length, the number one priority should be dispersion. There was simply not enough distance loss using shorter drivers to warrant fitting someone to a longer driver simply to pick up a few extra yards. The difference in distance between a shorter driver and a longer driver is often not that great. The study clearly indicates that each golfer is unique and should be uniquely fitted for driver length and that a thorough driver length fitting is an absolute must. From a fitting perspective, the fitter should not be afraid to go shorter with drivers. Fit the golfer firstly to the length that gives him or her the most control, secondly fit the golfer to a length at which he or she is comfortable and confident. The distance will take care of itself.
The data for best distance was taken directly from the TPS software and was taken as “total” distance.
0-8 Handicap — In this test group 33.3% had best distance with 43/44” drivers, 33.3% were longest with a 45” driver and 33.3% were longest with a 46” driver.
9-15 Handicap — In this group 70.55% hit the 43/44” drivers longest; 17.6% hit the 45” the longest and 11.8% hit the 46” the longest.
16-23 Handicap – In this group 44.5% hit the 43/44” drivers the longest; 22% hit the 45” driver the longest and 33% hit the 46” the longest.
24-32 Handicap — In this group 46.6% hit the 43/44” drivers the longest; 33.3% hit the 45” the longest, while 20% hit the 46” the longest.
Choosing the best dispersion pattern for any given club was based on the visual dispersion chart from the Trackman TPS software. The average dispersion of all shots, i.e., side total, was not the guideline used to choose best dispersion as it does not give the best picture of accuracy. For example, in an extreme case, if half the shots were 25 yards left and half the shots 25 yards right the side total would show Zero. However, if all shots were to the right by 10 yards the “side total” would show 10 yards Right. A quick look at side total only would lead one to pick the zero side total as the best, when in fact, the 10 yards Right would be the best choice. Therefore, the visual representation was used to determine best dispersion.
0-8 Handicap — In this test group, 67% of testers did best with the 43”/44” drivers while zero testers did best with a 46” driver. 33% of this test group did best with a 45” driver
9-15 Handicap – In this test group. 76% of participants did best with the 43”/44” drivers and 24% did best with a 45” driver. Zero % did best with a 46” driver.
16-23 Handicap — In this test group 56% did best with the 43/44” drivers, while 22% did better with a 45” driver and 22% did better with a 46” driver.
24-32 Handicap — This test group showed that 60% did better with the 43/44” drivers; 17% achieved the best results with a 45” driver and 13% did best with as 46” driver.
Throughout the four test groups, an average of 65% of golfers were more accurate with the shorter drivers. (43/44”); 27% did well with a 45” driver and only 8% did better with a 46” driver.
In this category, distance and dispersion were the factors used to determine the best result. In this category, golfers were asked for their input where they lost some distance with a shorter club but had better accuracy. Based on the raw data and the golfer’s input the best overall length was selected. The results are below:
0-8 Handicap – in this group 60% did best with 43/44” drivers; 40% did best with a 45” driver and zero percentage with a 46” driver
9-15 Handicap – 76.5 % did best with 43/44” drivers, 17.6% did best with a 45” driver and 5.8% with a 46” driver
16-23 Handicap – 55.6% did better with 43/44” drivers; 22.2% did best with a 45” driver and 22.2% did best with a 46” driver
24-32 Handicap –60% of this group did best with 43/44” drivers; 26.7% did best with 45” drivers and 13.3% were best with a 46” driver.
I’m sure you’ll find these results something to consider when you are looking to get fit for your next driver.