When is a driver that's breaking the rules not actually breaking the rules?

Question: I play a 48-inch shaft in my driver, but I’m thinking of adding a little end cap with my initials on it. But this would make the length of my driver over the 48-inch limit. Would this make my driver non-conforming?

Answer: First things first: Endcap? Clubs are tools, not jewelry. No carpenter worth his salt puts an end cap on his Estwing E3-16C hammer. Moving on. As for shaft length, we’re not fans of 48-inch drivers, or, frankly, anything significantly over 45½ inches. Unless you’re an NBA player, a longer shaft might only make it more difficult to achieve center-face contact. It’s also not necessarily true that a longer shaft will result in more clubhead speed that comes from creating a larger swing arc. Real distance comes from hitting the ball solidly, not just from speed, whose gains at best are marginal for golfers who aren’t competing in long-drive competitions.

To be fair, as drivers have gotten increasingly more stable, a longer (and lighter) shaft can help some players generate more speed, and making off-center contact on a highly stable driver can be less of a negative. When off-center hits start behaving more like on-center hits, swinging for the fences becomes more enticing. Still, there is ample evidence that most players will not swing a super-long, super-light driver faster, including a study from golf researcher Liam Mucklow.

Back to your question. Yes, you can add an identification tag, even stick a tee or a ball retriever, into the butt end of your driver without violating the length rule. It’s covered in the rules under Part 1, 2a, which allows “exceptions . . . for attachments that do not affect the performance of the club” such as “temporary, non-permanent attachments to the butt end of the grip.” That doesn't mean you can slap a shaft extender on the end of your original 46-inch driver and have it be OK under the rules. Shaft extenders clearly are used to enhance the performance of the shaft, but your ID tags wouldn't be an overt attempt to skirt the rules. 

Here’s another thing: If your clubs include stat-tracking sensors on the grip end, like Arccos or ShotScope, the extra length on those sensors won’t make your driver non-conforming either. They’re covered under that previously mentioned exception under the rules regarding length.

It's also worth noting that for elite competitions, there’s an often-applied Model Local Rule that limits shaft length to 46 inches. The fact is, there are very few drivers these days that appear at retail even at this length, let alone over it. There’s a reason for that: Very few drivers at longer than 46 inches have made much of an impact in the marketplace.

As a golfing species, it seems we’ve found a maximum length that optimizes our biomechanical range. In some cases, you can go outside the lines and still be within the rules, but tread lightly.