By E. Mike Stachura

Cut shot: Inside the Maxfli U/6 and Volvik Vista iV.

Who says golf balls are all the same? Volvik believes the dual core on its Vista iV, where the inner core is firmer than the outer core, creates a better energy transfer. That's the opposite of the prevailing wisdom in most balls, including the Titleist Pro V1x, where the outer core is firmer than the inner core to control driver spin.

Also thinking differently is Maxfli, which is touting its U/6 as the first six-piece golf ball. TaylorMade and Callaway have produced five-piece balls, but the Maxfli ball's four-mantle layer design is an effort to yield a straighter flight.

Still, dissecting a ball is not defining it, says Bill Morgan, Titleist's senior vice president of golf ball research and development. The Pro V1 has three pieces, the Pro V1x four. "Different layers are always involved, but to different degrees in different shots," he says. "The core is just one part of the golf ball. All the parts work together to create the overall performance of the ball."

Follow @MikeStachura

By E. Michael Johnson

It happens virtually every week: Reports from PGA Tour reps, ads from manufacturers and tweets from golfers all offering claims that tour players are seeing significant distance gains. How is that possible, you ask, when drivers are either close to or at the legal limit for springlike effect?

One of the reasons is that despite the endless hours pros spend getting "dialed in" to their equipment, not all players have reached their maximum efficiency off the tee. One only needs to look at Tiger Woods as an example. Although much has been made of Woods' resurgence with the putter this year (and rightfully so), less well-known has been his improvement in "driving efficiency," a statistic that combines a player's carry efficiency (his carry distance divided by his clubhead speed) and total distance efficiency (total distance divided by clubhead speed).

Although hardly a measure of how good a driver of the ball a player is, driving efficiency does say whether you're getting the most out of your swing off the tee, something in past years Woods had not achieved. From 2007 (when the stat first became available) in years he has played enough to qualify for a ranking (2007, 2009, 2012), Woods' rank in driving efficiency was 166th, 159th, and 92nd. Entering the Arnold Palmer Invitational, Woods ranked 11th.

To max out distance, players need to get the best match with their driver, ball and launch conditions. The key to efficiency? Almost without exception it is a combination of high launch with low spin. The 21 players in the top 20 in total driving efficiency on the tour average 1.52 degrees more launch angle than the tour average (12.65 degrees compared to 11.13 degrees) and spin it 245 revolutions per minute less (2,376 to 2,621).

Woods' stats speak to the importance of the launch angle/spin connection. In 2007 Woods was the epitome of a player whose launch conditions off the tee were the worst of both worlds as he combined a low launch (8.45 degrees) with high spin (3,343 rpm). This year Woods has a more desirable 11.76 degrees launch angle and a spin rate of 2,672 rpm. This has allowed him to maintain his length (300.3-yard average, a drop of just two yards from 2007), despite a loss of 4.5 miles per hour club- head speed during that same period.

Just because a player is efficient off the tee, however, does not necessarily mean they are long. Jin Park, Darron Stiles and Lee Williams, for instance, all rank among the top 20 in efficiency but average less than 275 yards per drive. Each, however, swings less than 107 miles per hour (the tour average is slightly above 113 mph) so they are getting the most out of what they have to work with. To do that most spend a lot of time looking at numbers, in an effort to find the right loft and shaft to produce the best result. Such work helped a player such as Park, whose swing speed is 104.42 mph, second slowest on tour. He found that a launch angle near 14 degrees with about 2,250 rpm of spin got him as much as he could out of his swing.

Conversely, there are several good players who are inefficient off the tee. Sergio Garcia, for example, is ranked 182nd (out of 183 players) in driving efficiency, the victim of a high spin rate. Freddie Jacobson (ranked 163rd), on the other hand, needs to boost his launch angle. His 7.78 degrees of launch is the third lowest on the PGA Tour.

Related: How Tiger's swing has changed

The reason for these numbers is not ignorance on the players' part, but rather a tradeoff they feel benefits their respective games. Garcia prefers the spin because he likes to work the ball. Jacobson prefers a more piercing trajectory over a high, arcing bomb.

As with all equipment decisions, you need to find the right balance for your entire game, not just the tee ball. But if you don't think you're getting the yardage you should from your driver, perhaps it's time to take a look at your own distance efficiency. You may not get the significant increases the ads claim, but you're likely to pick up a few yards.

TOUR STORIES

JIM FURYK // Shopping for strokes

Orlando isn't exactly known for its great shopping, but that didn't prevent Jim Furyk from making a stop at the Edwin Watts Golf store on Turkey Lake Road (just a few miles from Bay Hill Club & Lodge) on Saturday of the Arnold Palmer Invitational to peruse the putter corral. After taking a look at several models, Furyk went to the checkout counter with an Odyssey Versa #1 Wide model.

The purchase smacked a little of deja vu for Furyk, who bought a used Yes! Sophia putter at Joe & Leigh's Discount Golf Pro Shop at Pine Oaks GC in South Easton, Mass., for $39 the week of the 2010 Deutsche Bank Championship. Furyk used that putter to win the Tour Championship as well as the FedEx Cup. Whether Furyk has similar success with this putter remains to be seen, but one thing is certain -- he did not get quite as good a deal on this flat stick. According to the store, Furyk paid "somewhere between wholesale and retail" for the club, but as part of an Odyssey promotion received a limited-edition Phil Mickelson putter cover with the purchase.

NEW STUFF

CALLAWAY HEX Chrome+
PRICE: $36/doz.

Designed to produce high ball speeds for mid to fast swing speeds, this four-piece ball has a fast inner core and dual-mantle layer to help minimize spin off the driver.

callawaygolf.com

BAG ROOM

Among the many players changing putters at the Arnold Palmer Invitational was Rickie Fowler, who benched his Scotty Cameron by Titleist GoLo for an Odyssey Versa #7 mallet. Fowler had a good week on the greens, ranking sixth in strokes gained/putting en route to a T-3 finish. ... Phil Mickelson had a little less luck with his switch to a specially made Odyssey Versa #9 model. The club featured a Metal-X insert (which was black instead of silver), black shaft, milled alignment line on the flange with no paintfill and significant offset. After missing the cut, however, Mickelson said he would return to his Odyssey Black Series putter for the Shell Houston Open. ... Why did Karrie Webb have half her clubs with green Iomic grips and half yellow at the Kia Classic? Turns out green and gold are the traditional team colors of almost every Australian national sporting team and Webb wanted to show a little national pride.

Follow @EMichaelGW

By Mike Stachura

Spin city: These new balls promise more feel around the green.

Urethane isn't just a cover material for expensive tour balls these days. Lower-priced balls are using the material, too. Bridgestone's two-piece e5 ($28) features the spin of a tour ball on greenside shots. The ball is also designed to add a little backspin from the tee (to produce more carry) for players with moderate swing speeds and insufficient driver spin. Callaway's HEX Chrome+ ($36) has two mantles to mitigate driver spin, but it has the same cover formula as the more expensive HEX Black Tour. TaylorMade's RBZ Urethane ($30) wraps a soft urethane cover around a firm mantle for improved half-wedge spin and feel, and less driver spin. The polymer mantle on the Top-Flite Gamer Tour ($25) minimizes driver spin.

Is more spin on greenside shots helpful? Only you can know. Test on the course to see if there's a consistent performance benefit on your short shots and whether your missed drives are noticeably more playable.

Follow @MikeStachura

By Ashley Mayo

Callaway describes its new $20-a-dozen, ionomer-covered, low-compression Solaire ball as "designed to benefit a woman's game." One attraction might be the cost, says Steve Ogg, Callaway's vice president of global golf-ball operations.

"Although there are clear benefits for faster swingers to play [tour-level] balls, there are no significant benefits for slower swingers," he says.

The only advantage, he says, occurs on high-lofted shots around the green, where a softer urethane cover helps to produce a higher spin rate. "But do you want to pay an additional $20 to buy that ball?" he says.

By contrast, Michael Mahoney, director of golf-ball product management for Titleist, believes its best balls for women are its tour-played Pro V1 and Pro V1x because the golf ball has no idea who's hitting it.

Related: Check out Golf Digest's entire 2013 Hot List

"The notion that you'd fit a golf ball to someone's swing speed is based on the assumption they'll use that speed throughout the round," Mahoney says. "But all golfers swing slower as they get closer to the hole, and the golf ball needs to perform at all of those speeds. When you pay more for a golf ball, you're paying for performance."

Follow @AshleyKMayo

By Mike Stachura

Mid-rangers: Designed for average players, they act a lot like tour balls.

The most expensive balls get the attention, but now some are made with average players in mind that feature similar distance and short-game spin technology -- at $10 to $20 a dozen less than tour balls. Mid-price balls with soft covers designed for short-game spin include the urethane-covered Bridgestone e5, TaylorMade RocketBallz Urethane and Top-Flite Gamer Tour, as well as the soft ionomer-covered Srixon Q-Star.

There also are mid-price balls with multiple cores (Titleist NXT Tour) and multiple layers (Callaway Hex Hot, Nike One RZN). Not sure if a slightly lower-price ball is for you? Try a nine-hole test with a high-price ball and a lower-price model, says TaylorMade's Dean Snell, vice president of research and development. "If you can't tell the difference, then choose the cheapest one."

Follow @MikeStachura

By E. Michael Johnson

On the first hole of his semifinal match against Matt Kuchar at the WGC-Accenture Match Play, Jason Day had an iron shot from 166 yards into the green. Although Day pulled his approach, it normally would have carried onto the green. On this day, however, it was short, landing in the greenside bunker.

Golf Channel's Frank Nobilo quickly offered an explanation. "That's a freezing cold golf ball," he said. "You have to take that into consideration." Indeed, you do.

Jason Day at the WGC-Accenture Match Play Championship. Photo by: Andy Lyons/Getty Images

As the players began their semifinal matches, the temperature at the GC at Dove Mountain in Marana, Ariz., was a nippy 42 degrees and actually dropped to 39 degrees at one point.

What Day experienced, and what Nobilo was talking about, is not a mere myth. Cold weather affects golf balls due to the coefficient of thermal expansion. Although it may take a Ph.D. to fully understand this, the short version is that materials expand or contract depending on the temperature, thus affecting their properties.

A chill in the air also affects the ball after it is struck. Cold air is denser than warm air and creates additional drag on the ball. Former USGA technical director Frank Thomas has said the difference is about two yards of carry for every 10 degrees change in temperature. Going by Thomas' math, you're looking at a loss of six yards if you're playing in the 42-degree temps they had at the Match Play as opposed to 72 degrees -- or the difference between Day's ball finding the green on the first hole or finding the bunker.

Dean Snell, senior director of R&D, golf balls for TaylorMade, thinks Thomas' figures are about right. "When the golf ball gets colder, it can lose a few miles per hour in ball speed, which can mean distance loss due to speed," said Snell. "[The] optimum temperature range is 70 to 90 degrees. At 40-degree temps the ball can slow down and be shorter by 5 to 10 yards. But the balls are not 40 degrees when played. It takes a while for them to completely get to 40."

Snell added that cold temperatures also have an effect on other elements of the game. Players usually wear bulkier clothing and their bodies are not as flexible, further reducing swing speed that can result in fewer yards. How good a job golfers do at keeping their ball out of the frigid air also plays a role. For tour pros, that is often not an issue. Everyday players, however, tend to leave golf bags -- and balls -- in the trunks of cars, meaning they head to the first tee with golf balls considerably colder than room temperature.

In a 1980 Golf Digest article, Dr. Cary Middlecoff pointed out that, "At the Crosby, where it is almost always cold, I used to put a dozen balls under the radiator in my room to warm them up, then I'd alternate balls every other hole." In the same piece Bob Toski said cold weather affected grips as well, causing them to become hard and making the shaft feel stiffer. "I just had no feel at all with them," said Toski. Granted, Middlecoff and Toski played in the balata-ball era, but even modern players switch balls during cold weather, with some, such as Phil Mickelson, occasionally changing to a different model.

"I've changed to softer, lower compression balls when it is cold," said Mickelson at the Waste Management event in 2011. "A softer ball compresses more easily in the cold."

The tips section of Golfsmith's website offers advice on how to keep golf balls warm, including putting a towel in the bottom of a pot of two quarts of water, bringing the water to 120 degrees Fahrenheit (about the temp of really hot tap water), leave them in there for 30 minutes and then dry them and place them in an insulated food bag.

A check of the Decisions on the Rules of Golf reveals doing this is perfectly legal. Decision 14-3/13.5 essentially states that while golf balls warmed during a round are a breach of Rule 14-3, balls warmed prior to a round are OK. Doing so might keep you out of the front greenside bunker.

TOUR STORIES

IAN POULTER // Thoughtful changes

It shouldn't surprise anyone that Ian Poulter had 11 new Cobra clubs in his bag at the WGC-Accenture Match Play: a red ZL Encore driver, an AMP Cell 3-wood, a pair of AMP cell hybrids and AMP Cell Pro irons, plus a gap wedge. It also shouldn't come as a shock that Poulter tried some 300 clubs to create his new bag. After all, the Englishman's home in Orlando has an indoor simulator, two launch monitors, a putting green, club-repair bench and a swing-video camera system.

Poulter is a hands-on guy when it comes to his equipment, sometimes doing his own re-gripping (in which he places three layers of tape under his left hand and five layers under the right hand to offset the taper of the shaft, making the grip feel the same size in both hands). The extensive testing for his new clubs was essentially an extension of that.

"I think I'm probably more prepared than I've ever been," said Poulter at the GC at Dove Mountain. "The work I've done in the off-season, the equipment change, changing new shafts in all my irons, knocking a 5-wood out of the bag and putting in an extra wedge in the gap that I had. ... With the shafts [Project X Pxi 6.5] making my ball fly a bit higher, I can get at more pins as well."

NEW STUFF

PING TOUR GORGE
PRICE: $130 (Seven lofts from 47 to 60 degrees)

A trio of sole options (standard, thin and wide) offers variety while a new manufacturing process provides deeper, sharper-edged grooves. Hunter Mahan used the wedges at the WGC-Accenture Match Play.

ping.com

BAG ROOM

WGC-Accenture Match Play runner-up Hunter Mahan nearly enjoyed the same result as last year, but did so with a decidedly entirely different set of clubs. The lone holdover: his Ping i15 17-degree hybrid. Mahan also had a new addition at Dove Mountain -- he changed shafts in his Ping G25 3-wood to a Graphite Design Tour AD series that he said launched higher and spun less. ... Some players took advantage of the altitude at the GC at Dove Mountain, which sits 2,600 feet above sea level, by upping the loft on their drivers. Among those seeking a boost were Rory McIlroy, who jumped the loft on his Nike VR_S Covert Tour driver to 10.5 degrees; Rickie Fowler, who went from 7.5 degrees to 8.5 degrees in his Cobra AMP Cell Pro; and Lee Westwood, who went up half a degree in his Ping G25. All three use drivers that are adjustable for loft, making it an easy change. ... Graeme McDowell had two 5-irons in his bag at the Match Play -- a Srixon Z-TX Forged 5-iron as well as a Cleveland 588 MT 5-iron that replaced his 4-iron. McDowell had the club (which features a hollow construction and is akin to a utility iron) built 1/4-inch longer than his normal 5-iron. "It's stupid easy to hit," he said.

Follow @EMichaelGW