Will lead tape make your driver better or non-conforming? Yes. No. Maybe.

One of the great developments with the influx of adjustable clubs is the idea that every club can be dialed into each individual golfers’ requirements for things like ball-flight preference, spin optimization and, of course, corrective positioning of the center of gravity. The idea isn’t new. Golfers have been playing around with certain kinds of weighting since the days of Old Tom Morris, and the use of lead tape or other kinds of fitter tricks is still a relatively common option to get your driver working exactly the right way for you.

But in this modern era, with dozens of weighting options already built into your driver, compounding the search for better performance with the use of lead tape or similar tactics is likely unnecessary and might even risk making your driver non-conforming.

First, if you want a little extra mass in the head of your driver, make sure you’re working with a qualified fitter and an expert builder. Let’s say you know that you’re going to get better results with a shorter shaft on your driver, so you'll have to add a little mass to the head. If that driver has a weight port in the sole or other kinds of weights like a sliding weight, you likely can insert weights that are heavier than the standard setup. That will better match up with the loss of length in your driver for a more consistent feel with the shorter club. Generally speaking, you'll need to add about six grams of mass for every half-inch you cut off the end of the shaft, assuming you want the same swing weight. (By the way, you have to add much more to significantly move the center of gravity left or right or high or low. So much, in fact, that it might make your driver go from a reasonable head weight of 203 grams to an unwieldy 220 or so.)

Drivers that allow you to move weights front or back or heel to toe clearly have the capacity to change ball flight. In basic terms, moving heavier weight forward and lighter weight to the rear will result in a driver that produces less spin with a slightly lower launch for a given loft. The opposite is just as true. In the same way, if you position heavier mass toward the heel and lighter weight toward the toe, you'll increase the potential for a draw or a slice-correcting flight.

Our Hot List testing shows that re-positioning weight has a clear effect. We saw moving the weight to the heel or toe resulted in as much as 20 yards of fade or 27 yards of hook. We also saw as much as 1,000 rpm of spin change (approximately 30 percent) by adjusting the position of heaviest weights on a driver combined with reducing or increasing the loft.

But this is what happens when the weight is already built in on the driver. It is not unusual for the most forgiving driver models today to have 20 or more grams in a weight screw (and surrounding material) pushed to the back end of a driver to increase the moment of inertia (MOI) or moved into the heel side to increase the potential draw bias. There are several drivers with this kind of deep mass. They include the Ping G430 family, TaylorMade Qi10 Max, Cobra Darkspeed Max, Mizuno ST-Max 230, Cleveland Launcher XL2 and Tour Edge Exotics E723.

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But here's where it gets messy. It has to do with the rules regarding MOI, a measurement of the clubhead’s resistance to twisting, which is limited by the rules. As driver stock models have gotten closer to the legal MOI limit, they’ve put golfers in the position of creating a driver that would test out over the limit simply because they’ve added weight to the head to match up with a shortened shaft. Of course, it also depends where you put that extra weight. Moving more mass to the rear perimeter of your driver, sometimes as little as a few strips of lead tape, will increase the MOI to the point where the driver would test over the limit. If your driver already measures ultra high for MOI, three one-inch strips of lead tape might make it non-conforming. And the thing is, it would likely have no great effect on your driver’s stability on off-center hits.

One other downside to artificially boosting your driver’s MOI through the use of lead tape: It likely will raise the center of gravity, and that could result in unwanted extra spin, robbing your best shots of the optimal launch conditions to maximize distance.

In short, movable weight works in your modern adjustable driver. Fooling around with that precise balance of internal weighting not only might get you something that doesn’t play any better (and might play worse), it might get you a club that technically violates the rules.