Modern Designs - Modern drivers employ similar concepts to optimize the club-head design by using lightweight titanium alloys - one of the lightest metals used for golf club making. Some drivers such as Callaway ERC and Cleveland Launcher 460 COMP employ even lighter composite materials in conjunction with the lighter titanium alloys. These materials allow designers to become more creative with, and creating bigger and more forgiving club-heads. Such design concepts, together with the advanced shaft technology, have enabled designers to take advantage of benefits from longer shaft length, bigger sweet-area, lower and deeper center of gravity (CG), draw biased CG and gravity angle as well as better gear effect.

Some models utilize heavy tungsten inserts with titanium. Lightweight materials and thin metal wall forming technology allow designers to distribute more weight to the perimeter, which in turn creates a larger sweet area and provides more forgiveness on off-center hits.

Because of this type of lightweight technology, the club-head volume could become very large. Early metal woods generally did not exceed 195cc in volume, but today's titanium drivers could be as large as 460cc. The recent trend is to make the club-head larger, while the CG position can be different from one club to another (low/middle or shallower/deeper). It is clearly changing from the earlier trend (1999 - 2000) of medium sized lower deeper CG club-heads (250 -260cc).

In 2004, Taylor Made introduced a new driver - r7, which incorporated means to redistribute 24 grams of weight by employing removable four cartridges (like volts) - which made it possible for a golfer to choose from a total of six different conbinations of different CG positions and gravity angles.

Spring-like Effect - Springy materials to improve the initial velocity of golf ball are prohibited by the rule (COR 0.830 limit). As a matter of fact the Callaway's ERC Series were banned by USGA, while it was not in Europe. In any event, it appears that a noticeable new market trend is to legally utilize the spring-like effect for additional distance. By reducing (certain sections of) the wall thickness of club-face, or by employing a larger and thinner faceplate supported by a firm structure, the positive and legal spring-like effect seems to be attained (see the USGA 2002 Announcement.)

Callaway refers to as "variable face thickness or VFT". The Big Bertha Steelhead Plus Driver was built with the club-face having a thick elliptical area and thinner perimeter area. Mizuno's T-Zoid Forged Titanium Driver was equipped with a unique clubface - "dual wall thickness" or "CORTECH" (Coefficient of Restitution Technology) - that is thinner in a "C" shaped area closer to the heel to utilize the spring-like effect. These manufactures are claiming that the spring-like effect contributes to the higher ball's initial velocity. Callaway's Great Big Bertha ERC driver, as a matter of fact, was not conforming the USGA rule (COR 0.830 limit) due to the spring-like-effect, and therefore considered as an illegal club in the United States.

Loft and Face Angle - As today's drivers are mostly designed to launch high and spin low off the clubhead to gain more distance, you may want to change your idea of using a lower lofted driver such as 8 or even 9 degree loft. For average or even slightly longer players, 10 - 11 degree drivers may be more preferable than lower lofted clubs. Golf balls are changing as well. You need a higher lofted driver and tee up high to take advantage the modern technology.

Toe-down and Shut-face Phenomena - A large club-head offers many advantages such as a larger sweet-area, larger moment of inertia, and better ball spin characteristics; nevertheless, it brings disadvantageous effects in the total performance of the club at the same time – namely the toe-down and shut-face effects. With a large clubhead, CG of a clubhead is apart from the shaft line, and the centrifugal force acting on a clubhead bent the shat down (toe down) at the impact. In addition, tortional deformation appears on the shaft, which makes the face close. These effects are propotional with the centrifugal force and the position of CG relative to the shaft line (gravity distance) as well as the shaft properties - flex and torque.

Clubhead Shape - A Japanese club maker has made an attempt to minimize the length of CG/shaft line by means of employing a unique clubhead shape. The Saso MR Square Driver, introduced by Saso Grind Sports in Japan, featurs a large (380cc) hollow shape clubhead offering heel-toe weighted design made from SP-700 titanium. The clubhead and sole design allows to locate the CG closer to the shaft line despite the clubhead size and heel-toe weighted design to realize a bigger sweet-area. Although it is said that no one clubhead shaft combination produces better results for everyone, this is an example of unique design that can produce consistently better results for average golfers. Bore-through Technology - The bore-through design eliminates hosel (for instance, Callaway clubs) is for better feel, and kick back effect (quicker the better). Meanwhile, the inset hosel design appears to shorten the gravity distance (distance between shaft axis and CG) and therefore should be effective to minimize the toe-down and shut-face phenomena.

Gear Effect - The gear effect is an important function of the golf club (see "gear effect" for more details). A deeper CG design as well as the shape (convex) of the club-face need to be incorporated to optimize the gear effect. The CG of conventional stainless club-head drivers is closer to the club-face than those of persimmon and titanium clubs, which results in the inability to generate enough moment of inertia for the gear effect. Incidentally, it is also important to have design considerations to control the amount of spin (2,300 - 2,800rpm) for maximum distance.Adams takes the gear effect concept to a step further with the SC Series Titanium Driver featuring its patent-pending Asymmetrical Face Curvature system (AFC). As shown below, the AFC system is to change the ball trajectory by varying the shape of the clubface to fit each individual swing type and control ball spin and the amount of gear effect.



Face Inserts - The popular face insert is made of titanium alloy such as beta titanium (see "Materials" for more details). Lightweight inserts allow to distribute more weight to the perimeter, which can create a larger sweet spot for more forgiveness on off-center hits or can shift the position of CG to some extent. Face inserts made from titanium are considered harder than those made from steel, and inserts made from maraging steel are said to be harder than titanium. The hardness of the club-face per se, however, should not be an important factor to increase distance. Energy is lost in the collision between ball and clubface, and the energy loss is directly related to loss of distance.

It would be true that the harder the clubface, the less energy loss. However, because golf balls are significantly softer than any metals used for golf clubs, the majority of energy loss is on the ball side. Therefore, the energy loss can be reduced marginally by hardening the club-face.   There is a very good article in clubmakers' resource, "Hardness and distance or A myth is not good as a mile" by Dave Tutelman. It would be true, however, that a club-head and club-face deform in the collision, and the deformation could cause the energy loss. Ping believes that the structurally rigid club-head reduces deformation at impact and thus reduces the energy loss and transfer more energy to the golf ball for longer tee shots. On the contrary, the aforementioned spring-like effect is a result of deformation of the club-face, which is considered to transfer more energy to the golf ball.

Offset Hosel - There are many ideas for promoting draw balls or reducing the degree of slice balls. An offset club with minimum face progression may help reduce the degree of slice. Taylor Made, for example, claimed that its offset hosel helped keep the club-head behind the hands, making it easier to keep the face closed at impact, and that helps promote a right to left ball flight pattern. Another idea is to increase the gravity angle by designing the club-head accordingly. Callaway once had done that by positioning the tungsten screw in such a manner that the the gravity angle of the driver was biased toward the draw side ("draw bias"). 

 

Hosel offset (Source: Ping)

Ping's offset hosel approach is innovative. Having its unique hosel design which allows 14 different configurations, Ping TiSI Titanium Custom Fit Drivers offer draw or fade bias clubs. This design approach to control the gravity angle and the amount of face progression is distinctively different from those approaches of other manufacturers. Making the club face closed, or hook faced, is another approach, but that makes many golfers have difficulty setting the clubs squarely. Loft - Finding the appropriate amount of loft for your driver can be crucial for deliver longer and straighter drives. If your swing speed is more than 100 mph, drivers featuring 10 degrees of loft or less would be appropriate. For swing speeds between 70 to 90 mph, the loft should probably be no less than 12 degrees, and those with even slower swing speeds can maximize distance by selecting woods with between 12 and 15 degrees of loft.

Shafts - With longer shafts, golfers can achieve greater club-head speed, and therefore greater force to the ball and longer shots. However, it is critical to strike the ball at or near the sweet spot to hit a longer ball. It is also important to square up the clubface at impact for straighter shots. Driver shaft lengths run anywhere from 43" to 50", and today 44" and 45" are the most popular shaft length for men (in the past 43" was standard). Generally, longer shafts allow golfers to generate greater club-head speed, but longer clubs are harder to control. The appropriate length is one that allows you to hit the ball with greater frequency both solid and straight. In addition, the shaft flex, torque and kick-point are important parts of your club selection. As to the weight, most steel driver shafts weigh between 90 to 110 grams, while graphite shafts are between 65 to 90 grams, with many ultra-light models weighing 60 grams or less. For more details, go to our "Shaft Technology" page. 

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