There have been movable and sliding weights that shifted the CG horizontally toward the heel or toe to produce shots that, respectively, tone down a slice or calm a hook. There even have been drivers that independently from other settings can adjust the vertical center of gravity from high to low, an effort to either better match a player's specific impact position or effectively let a player choose between low spin or mid-spin.
Now, Nike is offering the option to control CG location in a front-to-back dimension. It's an idea we've seen in some sense with the first TaylorMade r7 driver where the heavier movable weights could be put in the forward position or the rearward position, and most recently with Mizuno's JPX 850 driver that was put in play earlier this year by Luke Donald. The new Vapor Flex driver ($500, available Jan. 30) features a weight cylinder housed flush with the sole that can be flipped so the heavier end is toward the face or toward the back of the driver. The weighting change lets a golfer alter launch angle and spin rate independent of the driver's other loft and face angle settings.
"Often in the fitting process, there's an opportunity for a final adjustment to develop the shot shape and ball flight the athlete is looking for," said Nate Radcliffe, Nike's director of engineering. "As the last step in the fitting process, that can be the difference between the athlete being comfortable with the fitting and really being able to compete with it on the golf course."
According to Radcliffe, there's about a two-millimeter difference in the CG location front to back. He says the change from front to back can increase launch angle by a degree, while the change from back to front can reduce spin by 300 rpm. The CG movement also affects the clubhead's moment of inertia, which is a measurement of its resistance to twisting on off-center hits. On the Vapor Flex, this means the back CG position has about a 300-point higher MOI. Theoretically, some better players may prefer a club with slightly lower MOI, since off-center hits are not as large a concern and because they might find it easier to manipulate the clubhead.
The Vapor Flex (left) is built on the same technology platform as Nike's Vapor Pro driver that Rory McIlroy recently put in play, as well as the Vapor Speed driver (below right, $300, available Jan. 30), which was also launched today. All three new Nike drivers include a redesigned sole cavity found previously in the Nike Covert and Covert 2.0 drivers. Radcliffe said the redesign included lowering and stiffening the back portion of the cavity to concentrate the flexing toward the front of the crown to improve ballspeeds.
Like the Vapor Pro, Vapor Flex also features the return of a sole channel toward the front of the club to improve the way the face flexes, particularly on low impacts. The channel, which was first part of Nike's VR drivers in 2010, has been completely redesigned, including some 37 iterations before a final version was settled on. It's designed to vary in flexibility (it's shallower in the center and deeper towards the heel and toe) to improve the way the face flexes on both on-and off-center impacts. "This is a completely new channel," said Radcliffe. "It does not have a uniform depth."
The drivers also feature a rotating hosel adapter that allows players to independently adjust face angle and loft. The head adjusts between 8.5 and 12.5 degrees with one of three face angles for a total of 15 unique settings. The new hosel is 30 percent lighter than previous versions.
The Vapor Speed features a larger footprint and a slightly higher moment of inertia than McIlroy's previously debuted Vapor Pro. The crown also slopes down more from front to back compared to last year's Covert 2.0 to yield a larger face area.