What’s 1,000 rpm of driver spin worth? We used Rory McIlroy’s swing to find out
Richard Heathcote
Of all the numbers a launch monitor spits out, spin tends to take the blame. It's the go-to explanation for a drive that balloons and comes up short, and "lower spin" has become the default prescription for anyone chasing yardage. What almost nobody can tell you is the exchange rate: how many yards a few hundred rpm actually buys.
So we put a price on it, using Rory McIlroy's swing.
At Golf Laboratories, Gene Parente's robot was set up to match McIlroy's driver delivery: 126 mph of club speed with a positive attack angle of 2.5 to 3 degrees.
The robot then hit drives at three spin rates, roughly 2,000, 2,500 and 3,000 rpm, while nearly everything else stayed static. Launch angle landed between 10.5 and 10.6 degrees on all three shots and smash factor sat at 1.46 or 1.47. On the 2,000 and 2,500 rpm shots, ball speed matched to the tenth at 186.7 mph.
That leaves spin as the variable doing most of the work. And in this case, it did plenty.
The price of 500 rpm
Three robot shots using Rory McIlroy's driver delivery (126 mph club speed), from about 2,000 to 3,000 rpm. Pick a measurement to see how it moved with spin.
The most obvious question is why we're running this test with elite-level swing speeds, when most of our robotic testing has centered around 90-95 mph, which aligns with the largest swath of male amateur golfers.
The simple answer is we've received questions about how drivers perform for golfers with speed in the tank, so we're obliging and starting with the apex predators who can move it faster than practically everyone on the planet.
Going from roughly 2,000 to 2,560 rpm resulted in an 8.1-yard drop in carry, dropping from 333.4 to 325.3 yards. It's the cleanest comparison in the test, since ball speed and launch didn't budge. In per-unit terms, every 100 rpm was worth about a yard and a half of carry at Rory's speed.
Add an extra 500 rpm at elite speeds, and the carry delta is even more expensive. At 3,000 rpm, carry fell to 312.4 yards, another 12.9 yards as spin moves into a suboptimal range. That number comes with a footnote, though. The high-spin drive left the face 2.1 mph slower than the other two, and at this speed each mile per hour of ball speed is worth roughly two yards of carry. Take out the four or so yards that belong to ball speed and spin is still on the hook for close to nine.
So call it eight or nine yards of carry for every 500 rpm. Stretch that across the full 1,000 rpm and the low-spin drive carried 21 yards past the high-spin one and finished 26 yards ahead once both stopped rolling.
If you're keeping track at home, that's a two-club difference.
Where the yards go
Robot shots using Rory McIlroy's driver delivery (126 mph club speed). Launch angle stayed between 10.5 and 10.6 degrees on all three, so spin is what bends the flights apart. Tap a spin rate to isolate it.
| Measured | 2,000 | 2,500 | 3,000 |
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Flight paths are drawn through each shot's measured launch angle, peak height, carry and descent angle; the curve between those points is approximated. Dashed line shows ground travel to total distance. One robot shot per spin setting. Source: Golf Laboratories robot testing, Foresight launch monitor.
So where did all that yardage go? Mostly up. Peak height climbed from 112.6 feet on the 2,000 rpm drive to 121.3 feet at 2,500 and 129.1 feet at 3,000, even though all three left the face at the same launch angle. Backspin is what creates lift, and once a drive has enough of it, any extra spin buys height and drag rather than distance.
What goes up has to come down, and the higher-spin drives came down steeper. Descent angle went from 38.3 degrees to 41.2 to 44, and hang time stretched from 7.7 seconds to 8. A ball falling at 44 degrees drives more of its speed into the ground, which helps explain why the total-distance gap ran five yards wider than the carry gap.
I'd take that part with a grain of salt, since how far a ball travels after it lands depends a lot on the turf. Carry is the number to trust.
What it adds up to
Each spin setting was a single robot shot, so treat the gaps as directional rather than precise to the yard. The trend is hard to miss, though. Every step up in spin made the drive fly higher, land steeper and finish shorter, and at McIlroy's elite speed it cost roughly eight or nine yards of carry per 500 rpm.
How much of this carries over to a slower swing is a different question. When we ran Titleist's GTS2 through the robot at 95 and 105 mph last month, lower loft (and the lower spin that comes with it) didn't buy any extra carry. With a level attack angle, the 8-, 9- and 10-degree heads all carried about the same, and when the robot hit down on the ball, the 10-degree head carried 12.5 yards past the 8.
If you swing like McIlroy and your driver is spinning near 3,000, knocking off 500 rpm isn't fine-tuning. It's the cheapest distance hack you'll find. It turns out spin deserves the blame it gets, at least at 126 mph.