Mickelson has positioned the gravity core in the low center of gravity position, according to Callaway. Mickelson, well known for his creative use of various drivers and fairway woods over the years, has a brand-new Callaway Big Bertha 2014 driver in his bag. He spent a lot of time doing what he does better than perhaps anyone else on tour – tinkering with his clubs.
"As I look back on 2013, I played some of my best golf and had some huge breakthroughs, but I did most of it without a driver," he said. "This year I have the best driver I've ever hit that lowers my spin rate just like my 3-wood. I drive it longer and straighter with my driver than I did with my 3-wood."
Generally speaking, players with above-average head speeds or those trying to prevent excessive spin will benefit from that lower center of gravity, which a creates a flatter, more penetrating trajectory accompanied by more rollout, Callaway explains. Golfers looking for a more controlled and workable ball flight and less roll, they add, might be better served by using the higher center of gravity.
Either end of the core can be inserted into the clubhead, allowing golfers to raise or lower the center of gravity and thereby alter their spin rate. When the heavy tungsten end is closest to the sole, it lowers the center of gravity and reduces backspin; when the tungsten end is closest to the crown, it raises the center of gravity and increases spin.
I was testing a taylormade r11s driver, which really launched the ball high in the air. A little too high, to be honest. It felt like it cut down on distance a tad. When I hit the Bertha straight, I hit it further. For the most part I was happy with the Big Bertha. The thing that I struggled with was keeping in the fairway. I tended to slice it hard out right. When I tightened up my swing I would keep in play, but there was always a risk of the big miss out right.
But the extra loft made the club more forgiving, and the distance given up wasn't that significant. I was consistently in the fairway, which is the number one thing I'm looking for.