When asked about the particulars of golf equipment these days, I often find it's easier to explain a facet of club design or fitting by drawing comparisons to my own set. So, just for fun, I'll take a few paragraphs and talk about why I play what I play, in the spirit of addressing a few of the fundamental and quirky facets of club equipment decision-making and fitting.
I should start by saying that I've been working on getting my set right for about 7 years. It started with a bug to read up on what was new with drivers back in 2003 as I prepared to replace my war torn Callaway Big Bertha from 1996. I landed on a few websites that revealed interesting information in what was new technologically and in fitting. It steam rolled from there as I started to tap into the various websites and compare model specs to what I was reading about as ideal for me in a new driver.
So, let's start with the "in play" club, as it used to be called. My driver is a KZG (www.kzgolf.com) SP700 model, 355cc, with 12 degrees of loft and a 1 degree closed face. It has a traditional pear shape (high toe), with a 22mm face progression, 11" x 11" bulge and roll, and 50.8mm face depth. It weighs 198g stock, with proprietary brazing welds connecting 3 pieces (head, sole, crown) and a 58 degree lie angle. The face is forged SP-700 titanium, with progressive face thickness (similar to variable face thickness), is 2.7mm thin (thinner than 6-4 Ti faces usually are), and a CT (Characteristic Time, or another measure for COR - Coefficient of Restitution) of 247, which is right near maximum. The shaft I use is a Grafalloy Comp NT, stiff flex, 64g weight, with a mid kickpoint and firm tip flex. The torque is on the low end at 3.1 degrees, and the length is a butt trimmed 44". The grip on all my clubs is Golf Pride Tour Wrap, 1/16 oversized, with one wrap of tape underneath. Overall, the swing weight is C8.
Why this driver works for me: first, the length. I played it at 45" for a while. My miss was a push and I was, at best, hitting the center of the face 7/10 swings. The shaft felt a little "boardy" as well, so I decided to gain additional control and feel by butt trimming the shaft 1". That immediately changed the swing weight by 6 points, which I offset with lead tape on the sole of the driver. It still plays at a somewhat lighter than standard swing weight of C8 (most off the rack drivers are D0-D2), but the proof is in the center strikes (better), less pushing of the golf ball as the primary miss, and in my ability to still get the distance the 45" afforded (funny how improving center strikes will do that). The shaft feels better too as it's slightly less than stiff as butt trimming will do that, plus the added weight on the head adds a bit of lag to the shaft and swing.
The feel at impact is unparalleled and I attribute this to the SP-700 Ti face. It's very thin, and can be, given the tensile strength of SP-700. It has a high elongation too which adds to the spring-like effect. Sound and feel are terrific and we all know they go hand in hand. SP-700 is an alpha/beta grade titanium manufactured in Japan. It's expensive, and can be found in many of your high end component clubs from KZG, Alpha, Bang, and Nakashima, but will also show up with a few of the mass market OEM's such as Titleist and Nike, in select models.
Having a pear shape, 355cc size and slightly closed face gives me the straight ball or draw I look for most days. I release the club later in the swing, and with a larger head or square driver, it's tough for me to have the face "catch up" on the downswing. With a smaller head, the COG is closer to the shafts axis of rotation, which helps square the face, and the closed face affords that extra split second too. The generous bulge of 11" helps too offset gear effect just enough to keep the shot on line. Remember, the lower the number, in inches, the more bulge in the face.
I come in steeper than average on all my shots which explains the 12 degrees of loft. I likely de-loft 2 degrees and need the extra loft to get me to the ideal launch angle. The face depth is certainly less than a 460cc head, helping me to shape shots when I want to, but i'm not good enough to count on that. My next driver might have a deeper face to offset the occasional curvy hook or slice. The downside to a deeper face can be aerodynamics, which is a hot topic today with Nike's new MachSpeed and Adam's Speedline series. There's proof in the pudding with recent testing showing that certain shapes add swing speed as others reduce it. From what I've read, square and slope back drivers slow down swing speed. Something to consider as a trade off to a deeper face and increase in MOI due to shape.
Face progression of 22mm is about right for a driver designed to be worked a bit, which this model is. A face progression that's less than 22mm, say 18mm, is generally found in drivers designed for high launch and for those that tend to come over the top a bit and slice. There's no such thing as offset in drivers! You'll never find a driver that has the front of the hosel ahead of the leading edge. What you will see is a driver with less face progression or more "onset", which is the measurement of the front of the hosel TO the leading edge. Face progression is the measurement of the CENTER AXIS of the hosel to the leading edge. There's a difference, and more onset or less face progression will help square the club a bit and move the COG further back for that high launch, squared-up shot "casters" crave.
With the butt trim, the kick point moved up an 1". Not a real factor but does help keep the spin manageable with a 12 degree driver where I swing about 100 MPH. The torque at 3.1 degrees helps square the face and reduce spin at this swing speed but too little torque can add to the push phenomenon, although that's lessened now with the 44" shaft. ultimately, torque is less a factor than flex profile (frequency) and length specs in a shaft.
Then there's welding. Here KZG uses a proprietary welding which isn't a traditional bead welding. Welding is critical for a driver's performance. You must look into how the 2, 3 or 4 driver head pieces are assembled and here's why: First, if you're looking for a driver that has a COG low and deep, it must have a brazing or plasma weld. I say this because it's likely the the face was constructed separately from the head and is attached by a weld. If it's a traditional bead weld, the weight of the bead welding can offset the effect of the weight used internally to move the COG back in the first place. Second, brazing and plasma techniques are superior in helping a driver maintain it's power, or said another way, in reducing power leaks. COR is key to distance and the proper welding will maintain energy transfer to the ball through the face.
And finally, with welding comes face design and we all know about variable face thickness and cup face from the advertising. Great designs all in helping maximize those mis-hits that are sure to happen. VFT has the outer edges of the face thinner than the center to maintain ball speed. Cup face uses a pull face construction of sorts to improve the face's spring like effect across the entire face, with brazed welds beyond the face as it wraps around the head, to ensure energy transfer to the ball. Look for such designs. My driver has progressive face thickness and it's a big help. How do I know? For a 1/2" off-center hit I lose about 7 yards. That is, from what I've read, better than average and this with a 355cc head that is sure to have an MOI less than 4000 g-cm squared, unlike you're run of the mill 460cc. It's in the face!
I'm tapped out on the driver...for now. More on the other clubs in another blog entry.
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