British Open 2021: Driver testing is expected to return at Royal St. George's. Here's what you need to know


Andrew Redington

The Open Championship is back after a lost year due to the the COVID-19 pandemic and with its return is expected the continuation of what’s become an unusual custom of late for the R&A: testing drivers for conformance.

You do remember that, right? It was done in 2018 at Carnoustie, when players were warned in advance that their clubs might be randomly selected for inspection. All of the roughly 30 players picked had their driver pass, with player anonymity maintained. However, when testing occurred again at the 2019 Open at Royal Portrush, three were found to be over the allowable limit for Characteristic Time (we’ll get into what that is exactly in a bit), including one owned by Xander Schauffele, who had plenty to say on the subject.

Before we go any further, let’s get one thing straight: No player is trying to cheat. None of the manufacturers are trying to cheat. There are reasonable explanations for why some CTs approach/exceed the limit. And the benefit of a driver slightly over the limit, most R&D experts will tell you, is shockingly low.

The Characteristic Time (CT) test involves a small metal ball swung from a pendulum striking a spot on the face with the amount of time the metal ball “dwells” on the face captured. The longer it stays on the face, the springier the face. The test is not limited to the center of the face, but several points on the face where impact might occur.

Under USGA and R&A rules, drivers must have a CT limit of 239 microseconds with a tolerance of 18 microseconds, meaning a club can have a CT measurement of 257 and be conforming. In layman’s terms, it’s like knowing the speed limit is 65 miles per hour but that you won’t get a ticket driving your car unless you’re going 75 or more.

Now that you know that bit of information, a good rule of thumb is 10 microseconds (which would be highly unlikely that any driver would be over the limit by that much) might equal one extra yard of distance. That would mean one microsecond (the absolute difference between passing and failing the CT test) might equal the diameter of two golf balls in terms of a distance gain.

Of course, this all begs the question: If the benefit is so small and the players aren’t intentionally cheating, what is going on?

As manufacturing has gotten better and manufacturing tolerances tighter, clubs are being designed to go deeper into the tolerance zone—raising the possibility of one potentially going over the limit. To be fair, manufacturers vigorously test all the drivers they send to tour, including “tour spicy” drivers that are under the limit, but perhaps only by a few microseconds.

Another reason drivers get so close to the line is that while PGA Tour players don’t have CT machines, virtually all of them own a launch monitor, allowing them to see ball-speed numbers. When testing drivers, it would go against common sense along with being occupationally negligent to not choose the driver with the fastest ball speed. And this, while perfectly legal, is perhaps a recipe for danger as those drivers are likely the ones with the highest CTs. Plus, no two CT machines are the same, and a driver can possibly record two different results on two different machines, including one reading being just under and one being just over.

Conforming drivers also can become nonconforming over time without a player knowing it either through play or by alterations made to the club. Although most drivers will crack before reaching that point, some older drivers played over time certainly run that risk as the face flattens or endures some metal fatigue. The addition of weight within a driver head can also cause issues. Adding weight in certain spots can raise a driver’s CT without a player being aware of it. That normally would not be a problem, but if you start with a driver at 255 CT and add a few microseconds, a red flag goes up. It is one of the reasons the USGA and R&A are looking at tighter tolerance limits going forward.

In fact, a USGA notice to manufacturers in October 2017 changed the rules so a player would not be retroactively penalized for using a club that originally was conforming but was discovered to be nonconforming later on.

Given that, it’s not so much a competition problem—although it would be pretty bad for any player to have their “gamer” driver taken away just days before a major championship—as it is a public-relations issue for the game if the R&A were to find more drivers failing the test this week at Royal St. George’s. Those who simply read the headlines will see that Player A was caught with a hot driver and jump to all sorts of conclusions, and unfairly so. Schauffele dealt with some insinuations, which were unfair to him and not a good look for the tour.

Perhaps the memory of 2019 is fresh enough that players have taken extra steps to ensure their drivers are nowhere near the limit as they head to St. George’s. No doubt, a lack of hot driver hysteria would be a welcome change.