Golf ball testing has become one of the hottest topics in the sport since the USGA and R&A proposed a new Model Local Rule that, if enacted, might force elite players to use golf balls that won’t go as far as balls currently on the market.
Some see this move as potentially bifurcating the game by forcing the best players to use different equipment than recreational golfers. Others see it as a long overdue move that would rein in distance for the strongest professionals while not affecting recreational golfers – the vast majority of players.
Golf’s governing bodies are in a comment period in which stakeholders such as golf equipment companies, professional tours, golf course operators and others can provide feedback on the proposed Model Local Rule. So far, equipment companies such as Titleist, TaylorMade and Bridgestone have voiced displeasure and skepticism, noting that a fundamental part of golf is that everyone plays the same course and is governed by the same rules, including equipment rules.
That concept, to some, is a unifying trait, but the USGA, R&A and the Model Local Rule’s supporters see it as a way to keep historically significant courses playable for championship-level events. They want to keep shotmaking in the game and reduce the need for courses to be lengthened, which would cost course operators money and have a greater environmental impact.
Most golfers don’t know how golf balls are tested, but understanding the process can help you understand the proposed Model Local Rule and how it could affect elite golfers. Here is how it works.
Acquiring the balls
For a ball to be added to the Conforming Ball List and be deemed legal, a manufacturer must submit samples for testing by the USGA and the R&A. That means sending two dozen prototype balls to the game’s governing bodies. In the case of the USGA, that is the USGA Research and Test Center, a 20,000-square-foot laboratory and office building in Liberty Corners, New Jersey.
If you walk into a PGA Tour Superstore or Dick’s Sporting Goods and look around, you might think testing balls should be easy because you likely will see five or six brands selling at least three or four different models each. However, the USGA and R&A are sent far more submissions than you will see on shelves in stores. In a typical year, the USGA tests nearly 500 balls, and the R&A tests almost 850. After the prototypes arrive in New Jersey or St. Andrews, Scotland, for testing, it takes about three to four weeks for processing and testing procedures to be completed.
Meeting the size standards
Rules govern the symmetry, size and weight of golf balls, so each submission is closely measured and examined.
According to the USGA Rules of Golf, a ball’s weight shall not be greater than 1.62 ounces and the diameter of the ball can’t be less than 1.68 inches. It also has to be symmetrical, so no matter how it rests on the ground or a tee, the same shape is presented to the player. In other words, it has to be round.
Checking these standards is critical because a heavier ball could fly farther, all things being equal, because it will not be slowed down as much by the air. Similarly, a smaller ball would be more aerodynamically efficient and less affected in flight by drag, so it could fly farther too.
Robot testing
If the prototype balls pass the size, weight and shape tests, they are tested to see if they stay within the Overall Distance Standard. By rule, no golf ball can travel more than 317 yards when tested, plus an extra three yards for testing tolerance, making the actual distance limit in the tests 320 yards.
Two tests are performed to gather data and measure if a ball conforms to the Overall Distance Standard limits. The first test involves a robot affectionately called Iron Rugge, an homage to Dick Rugge, the USGA’s longtime senior technical director who retired in 2013. Before testing prototype balls, the robot swings a test driver specially made for the USGA tests and hits a series of balls that were produced for calibration.
“We went to manufacturers and said look, we want to have a standard club and a standard ball to do our testing, and we want to have it be available to anybody that wants to mimic the ball testing being done by the USGA,” said John Spitzer, the USGA’s managing director of equipment standards. “We asked the manufacturers if they would be willing to provide clubs and no one wanted to provide clubs for us, so we went to Fusheng (a Chinese company that is the largest golf clubhead manufacturer in the world).”
Fusheng produced a driver specifically for USGA testing, but it is available to anyone who wants to buy one. The titanium club has a 360-cubic-centimeter volume, and while that is smaller than today’s drivers, the size is irrelevant because, unlike us, the robot always hits the ball in the center of the face. A reduction in ball speed and distance due to twisting is not an issue for the robot.
The USGA made the same request to manufacturers for golf balls that could be used to calibrate the robot.
“Bridgestone was the one that said yes, we’ll make you balls for your calibration, and we’ll make them available to all the other manufacturers as well. They can buy them from us,” Spitzer said. “Those balls are all marked ‘USGA Calibration.'”
Before prototype balls are tested, USGA researchers set up the robot to swing the test club at 120 mph and it hits a series of calibration balls until it produces a shot with a 10-degree launch angle and 2,500 rpm of spin. Two launch monitors in the testing cage provide data to the researchers after every shot.
Once that setting has been established, the calibration balls are removed from the test, and the prototype balls are hit. In this way, the USGA knows that only one variable is being changed – the ball – so any differences in speed, spin and launch angle can be attributed to the ball, not how the robot is swinging the club.
“Every ball will come off differently, depending on its construction,” Spitzer said.
Indoor range data collection
In addition to testing prototype balls using a robot and club, the USGA and R&A fire balls down a 70-foot tunnel called the Indoor Test Range and study their flights.
The tests involve a machine similar to an automatic pitching machine, except it is much larger. Two metal wheels positioned vertically spin very fast, and one by one, a technician drops balls into a pipe from a safe position behind plexiglass. The balls roll into the test area and between the wheels, which then fire the ball forward like a golf shot.
A technician can change the speed of the spinning wheels to mimic different shots hit with various clubs.
“We test balls at 15 different speeds and spins,” Spitzer said. “We will test it all the way from when it leaves the club until it lands. In order to determine how far a golf ball goes for conformance, it requires 360 shots in the Indoor Test Range. [Our technicians] can do that in a matter of minutes.”
The advantage of the Indoor Test Range over testing outdoors, as the USGA did in the past, is that atmospheric conditions that can affect performance – such as wind, temperature and humidity – are taken out of consideration. This makes for a level playing field every day and in every test, so the USGA can accurately measure the aerodynamics of a golf ball in flight, combine it with the data gathered by the robot and create a very clear performance picture for any golf balls a manufacturer submits.
How the tests could change in 2026
The Model Local Rule the USGA and R&A are proposing would allow events and tours for elite golfers to mandate that players use golf balls tested under different conditions than you just read about.
While the Overall Distance Standard of 317 yards would not be changed, golf balls for elite events and tours would be tested with a clubhead speed of 127 mph instead of 120, and the launch angle would be increased from 10 degrees to 11 degrees. Additionally, the spin rate would be reduced from 2,500 rpm to 2,200 rpm. The USGA and R&A say this more closely mimics the conditions created by today’s biggest hitters.
Golfweek has spoken with numerous equipment makers, and all of them said that nearly every premium golf ball in use on the PGA Tour, DP World Tour, Korn Ferry Tour and other elite circuits would be deemed non-conforming under those new parameters.
Equipment makers who want pros and possibly elite amateurs to use their golf balls in competition would have to make new balls that could pass the tests. Golfers such as Rory McIlroy, Jon Rahm and Justin Thomas will not be able to hit these balls as far as current balls.
