At 01:24 PM 5/30/2006, Bernie Baymiller wrote:
What makes these driver heads with adjustable weights work as
advertised? Is it all hype? And, it is conceivable that they don't
work as well as a well designed driver head without the weights?
Good topic, Bernie.
I'll take a cut at it...
Move the weight back and toward the heel and the bulge is off center.
You're probably the only person on the forum that would think of
bulge first. I understand why -- it's genetic. :-)
But it's really simpler than that. The effect that really at work
would kinda' overwhelm the more subtle interaction between bulge and
CG -- if it did anything at all. (I'll get back to that cryptic remark later.)
Here's what's supposed to happen:
* Move the weight back and you're increasing dynamic loft
(the forward bend of the shaft). That makes for a higher trajectory.
* Move the weight toward the heel, and you're increasing the
area of the face that will give hook gear effect. That is, even with
impact in the center of the clubface, the CG is toward the heel, so
the rotation gives hook spin.
* Move the weight toward the toe, and more of the face gives
a slice gear effect -- same explanation as above.
So does it work, or is it hype? If you move enough mass, you can make
a significant change in the CG and start to notice the change in
trajectory. But you need to move a lot more mass than the popular
adjustable-weight clubs do. Tom Wishon estimates that you have to
move something like 40g to have a noticeable effect, which is why he
designed his adjustable-weight driver with so much movable mass.
Taylor-Made, OTOH, moves so little mass that the CG can only be moved
about 1/10". Even a really good golfer has a variation of where the
ball strikes the clubface, and that variation is more than 1/10". So
bottom line: that isn't enough to generate a significant effect on
the trajectory.
So, at least with the TM R7, it's hype -- with enough theoretical
underpinning that they can say if challenged, "Well, it gives A
LITTLE effect -- even if it's too small for a real golfer to notice."
(That's pretty much what they did with Bubble shaft over ten years
ago. The weight redistribution in the shaft allowed for 1/2% increase
in clubhead speed, and they advertised the hell out of it even though
it was just barely on the verge of being measurable.)
A friend of a friend did an interesting experiment over a year ago.
He got together a few low-handicap golfers, and had them hit drives
with R7 drivers. Every three shots, he'd take the driver and move the
weights, tell the golfer what he did (e.g.- "higher" or "more
hooked"), and let them hit more drives. What they didn't know was
that he had a random schedule for what he did, and a DIFFERENT random
schedule for what he TOLD THEM he did. When he analyzed the results,
the trajectory was only randomly related to the weight placement.
However, the trajectory was pretty well correlated to what HE TOLD
THEM he did. (I can see TFlan grinning from ear to ear now.)
BTW, I'm not saying the R7 is a bad driver. I think it's actually
quite well-made and gives good results for a lot of golfers. But the
adjustability feature is hype.
Hope this helps,
DaveT
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