Shaft profile and effects

[magicmarker]

This from MacKenzies presentation at ASII (segment 1, about 1:35): The clubhead kicking forward into impact does not increase club head velocity because the release of shaft torque that causes the kick simultaneously slows down the hands.

And related: a change in shaft stiffness will not increase clubhead velocity significantly (this confirmed by Woods' tests at Ping). But changing stiffness will change the amount the club is dynamically lofted and dynamically closed.

Another interesting point from Woods: if a shaft is well made to begin with there is no need for "puring" or "spining".

Has anyone here bought the ASII video?

I didn't intend to mislead and I apologize if I have. I pulled that quote because to visualize what is being proposed is very different than the idea of sustaining lag or the picture on the cover of Hogans 5 lessons book.

 

[mgranato]

I always find these speed/acceleration graphs interesting to look at. Both of these shafts are the same flex (driver and 3wood), but guess which one is not a great fit based on the graphs?

 

[birly-shirly]

The shaft that had the driver accelerate pretty dramatically into impact - was that performance replicated consistently across multiple swings?

 

[Frans@France]

Listen, i am no scientist and am not going to go against what these scientists have discovered, how ever there is the "human" element. I've done a lot of fittings over the years and humans will do allllllllllllll kinds of things to their swings to make "a shaft" work. This can affect speed and face angle.

It's a bit like chicken or the egg but none of the less it happens.

Jim, I agree and that's why I stated that you should read and then question why the researchers deleted the first few shots to get concistant data

 

[birly-shirly]

Frans - what was your concern about letting the test subjects see ballflight?

I think the researcher painted the various shafts so that they looked identical. Sure, they're likely to react to the ballflight that they see, but isn't that part of real-life too? Surely you'd expect to see ballflight if you were being fit for a shaft?

 

[mgranato]

The shaft that had the driver accelerate pretty dramatically into impact - was that performance replicated consistently across multiple swings?

Yes and no.

As the swing speed ramped up from "lazy" (light blue line) to more "brisk" (dark blue line), you can see how the driver shaft started to lose its composure compared to the 3 wood shaft. The club went from a nice steady acceleration slope and stable speed into impact to a big speed and acceleration "dump" right before impact. That big up tick in the acceleration profile is evidence of a shaft that is too weak for that swing speed. The up tick was replicated consistently, but that led to some inconsistent results.

Both shafts had the same letter flex (X) and both shafts were premium shafts. A lot of folks are kinda led to believe that the letter flex of a shaft determines how it plays, but it's the profile of the shaft that really matters when you get down to it.

 

[ZAP]

I guess tax return and the new computer so I can buy ASII cannot get here soon enough. The only computer I have now is the MacBook Pro from the school system. Great for using but I cannot really put anything on it that is not school related with a good conscience.

 

[mgranato]

I guess tax return and the new computer so I can buy ASII cannot get here soon enough. The only computer I have now is the MacBook Pro from the school system. Great for using but I cannot really put anything on it that is not school related with a good conscience.

Don't they still teach science in school... problem solved.

 

[birly-shirly]

Yes and no.

As the swing speed ramped up from "lazy" (light blue line) to more "brisk" (dark blue line), you can see how the driver shaft started to lose its composure compared to the 3 wood shaft. The club went from a nice steady acceleration slope and stable speed into impact to a big speed and acceleration "dump" right before impact. That big up tick in the acceleration profile is evidence of a shaft that is too weak for that swing speed. The up tick was replicated consistently, but that led to some inconsistent results.

Both shafts had the same letter flex (X) and both shafts were premium shafts. A lot of folks are kinda led to believe that the letter flex of a shaft determines how it plays, but it's the profile of the shaft that really matters when you get down to it.

Yep. It's a strange mistake to make, given how many shafts there are and how few flex designations there are, but I gather it's a common enough mistake regardless.

 

[mjstrong]

Please examine the TT ShaftLab downswing shaft loading profiles posted on this topic thread and decide if there are different "feel" loadings.

Many call themselves "feel" golfers but few are willing to quantify their "feel" sensations into something even semi-objective. Is it because "feel" is something intimate and special, and not to be questioned?

I like the loading profiles.

I agree that there are different ways to load the shaft in the golf swing, and that different methods will be better suited to certain shaft characteristics. I know that I perform much better with certain specs than others.

Okay, let's question "feel."

Perhaps "feel" is too general a term, and that certain "feels" will eventually be categorized and quantifiable. I'd be good with that.

Do you think that what people refer to "feel" is largely (or completely) related to the loading profiles?

 

[Frans@France]

Frans - what was your concern about letting the test subjects see ballflight?

I think the researcher painted the various shafts so that they looked identical. Sure, they're likely to react to the ballflight that they see, but isn't that part of real-life too? Surely you'd expect to see ballflight if you were being fit for a shaft?

They were looking for the relation between shaft en swing. However they found out that every golfer needed a few shots with every shaft tested before the swing- and club- data became consistant. They removed those shots from the conclusion and marked those shots as "warming-up issues". If they would have had a test without showing ballflights (so all feedback removed except body/feel) and all shots had been inconsistant then it is not a warmingup issue but the real relation between shaft and swing.

 

[birly-shirly]

Thanks Frans. I think I understand. But if you don't throw out the "warming up" shots, and you don't allow the player to see ballflight - isn't there then a risk that what you're actually testing is how similar the test shaft is to the player's usual driver set-up?

 

[Frans@France]

Thanks Frans. I think I understand. But if you don't throw out the "warming up" shots, and you don't allow the player to see ballflight - isn't there then a risk that what you're actually testing is how similar the test shaft is to the player's usual driver set-up?

If (only if) there would be inconstant data for almost all shots then indeed there would be a rather large chance that if one of those shafts would be close to the shaft played the data for that shaft would be less inconstant.

However that could then prove the point that there is indeed a relation between club and swing, where instead now by throwing out the (imho) important data proves exactly the opposite!