If the head was truly forward of the shaft prior to impact, it would indicate that the shaft had dropped below its peak speed or be decelerating with respect to the hands. The primary cause of it showing up as being ahead of the shaft is the affect of Centrifugal force pulling down on the head C. G. which is aft of the shaft thus causing a face up or head ahead of the shaft deflection. This later deflection has nothing to do with the Kick of the shaft since it builds up slowly as club head speed builds up during the swing. If we take out the imposed centrifugal force deflection the shaft should be at straight and square for the best performance.
llhack > [Original Message] > From: <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > Date: 10/3/2003 10:43:55 AM > Subject: Re: Re: ShopTalk: FUJIKURA PRO VISTA 60 > > While this looks good on paper, it doesn't hold up under the high speed camera. On the 'textbook' swing, we know the shaft is bowed to the target just before impact. In this same manner, it has also 'released' from a twisting standpoint, causing the toe to lead the heel. A shaft with a higher advertised torque will have 'released' more, typically increasing the draw potential. As Alan added, the larger driver heads do provide more resistance to this release, but the general concensus is that the higher the torque rating, the more right-to-left (for righty). Extremely low torque shafts produce fades for players who are unable to load the shaft sufficiently to allow it to release and square the face before impact. > > Check out Maltby's book for related data - he's covered this a long time ago. > > > > > > > From: Alan Brooks <[EMAIL PROTECTED]> > > Date: 2003/10/03 Fri AM 10:01:28 EDT > > To: [EMAIL PROTECTED] > > Subject: Re: ShopTalk: FUJIKURA PRO VISTA 60 > > > > Boy I wish someone in the golf industry would change the way we talk about > > the torsional stiffness of a shaft. Your customer is right, of course, a > > shaft no more has 'torque' than a spring has 'force'. Both have resistance > > to deformation, in the case of a shaft and its resistance to 'twisting' we > > call this its torsional stiffness. Unfortunately people started using the > > angular deformation that a shaft experiences when subjected to a standard > > 'twist' (one ft-lb in this case), so the less torsionally stiff the shaft > > is the higher the number. Our rating system is inversely proportional to > > torsional stiffness, which causes people all kinds of comprehension > > problems. And then people started calling this angular deformation > > 'torque'. Sigh. > > > > Now to your question. The shaft is a torsional spring between your hands > > and the club head. The stiffer the spring (the lower the 'torque' value) > > the more compliant the club head is to the motion of your hands, in other > > words the more closely the club head will follow the motion of your hands, > > or the less 'lag' there will be between the club head and your hand > > movement (just like with shaft longitudinal stiffness). The resistance to > > twisting comes from the moment of inertia of the club head about the > > twisting axis (the hosel axis in simplest terms). This is why large club > > heads are more difficult to 'close' than smaller ones, they have a larger > > MOI about the hosel axis (they also have a larger MOI about their own > > center of gravity, which makes them more 'forgiving'). > > > > When your customer said that a higher torque shaft makes it easier to draw > > the ball, I suspect he was thinking "A higher torsional stiffness shaft > > makes it easier to draw the ball.", which is probably true, there is less > > lag between the closing of the hands and the closing of the club face > > making it more likely that the club face will be slightly closed at impact. > > > > 'Torque' is the rotational 'force' that the hands apply to the butt of the > > shaft, the club head moment of inertia about the twisting axis is what > > resists that 'torque', and the shaft is what connects the two. The > > torsionally stiffer the shaft (the connection) the more tightly connected > > the hands and club head are. 'Torque Value' is the number we assign to > > indicated the torsional stiffness of a shaft, which, unfortunately > > (especially since people seem incligned to shorten this to simply > > 'torque'), is inversely proportional to torsional stiffness, which is what > > we really should be talking about. > > > > How's that for confusing? > > > > Alan > > > > > > At 02:48 AM 10/3/2003 -0400, you wrote: > > >In a message dated 10/2/2003 6:52:22 AM Pacific Daylight Time, > > >[EMAIL PROTECTED] writes: > > > > > >>At 07:05 AM 10/2/03 -0400, [EMAIL PROTECTED] wrote: > > >> >...the torque in relationship to relative stiffness or frequency is a > > >> >fitting variable that is often overlooked when fitting a shaft to an > > >> >individual. If we are talking frequency which only tells you half a story, > > >> >a 250 cpm shaft @ 2 degrees of torque will feel and perform different than > > >> >a 250 cpm shaft @ 5 degrees of torque. Tom Wishon had a chart that had a > > >> >relationship between swing speed torque and frequency with adjustments for > > >> >frequency to torque relation a very useful tool for adjustments. > > >> > > >>Charlie, > > >>I don't remember ever seeing this curve -- explicitly anyway. Where did you > > >>see it? > > >> > > >>That is not to say that Tom didn't implicitly give us all the info for the > > >>curve. In fact, he has published the info at least twice that I know of. > > >> > > >>* In 1991, he and Jeff Summitt co-authored the book "Modern Guide to > > >>Shaft Fitting". If you plot their DSFI formula, it relates frequency to > > >>torque for the same subjective "stiffness". > > >> > > >>* In 1996, Tom's "Modern Clubfitting" book has a table of RSSR numbers > > >>that can be similarly plotted. > > >> > > >>When you plot both of them, you can see that he felt torque was less of a > > >>factor in 1996 than he did in 1991. His view has been changing over time. > > >>(That's not a bad thing. We live and learn. I certainly have learned a lot > > >>about how golf clubs work in the last 5 years.) > > >> > > >>Cheers! > > >>DaveT > > > > > > > > >Hi Dave and all, > > >I had an interesting discussion with a customer tonight who correctly > > >pointed out that a shaft does not have torque on account as it has no > > >horsepower it merely has resistance to torque, on this we agreed, where we > > >dis agreed was that he felt that a shaft with more torque would help him > > >draw it more, and I felt that the more the torque the more the head would > > >resist squaring, he claims to have data to support the opposite, this from > > >a Dr Joe Corvi who is supposedly the Only guy who understands and can > > >relate all of Einstein's theories > > >? > > >David > > > >
