Spin Loft - Backspin - Attack Angle

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Is spin loft the same thing as backspin or is this a term created by Trackman for a new form of measurement of the golfball at impact?

How does one increase their attack angle without increasing backspin? Swing more around to lessen their VSP??
 

Kevin Shields

Super Moderator
Spin loft is the difference between AoA and dynamic loft. If you have a level strike and deliver 20 degrees of loft your spin loft is 20. If you hit up on the ball 5 degrees and deliver 20 degrees of dynamic loft your spin loft is 15 degrees. You can up up, level or down and not increase or decrease spin if this "spin loft" number stays the same. The only thing that would change with a center hit would be vertical launch angle.
 
How is the spin loft number useful? It doesn't appear to be backspin and I know its the difference between the AoA and DL, however, I don't know why its useful. Is it useful for just the driver or every club? I'm trying to understand the why behind this metric.
 
So how can one use this measurement to determine shot dispersion (like we do with face angle and path) if at all?

Is there a normal range like we have with face angle vs. path?

Where are the other 55???? (somewhat kidding)
 
In loose, layman's terms, think of: Backspin = SpinLoft X Clubhead Speed

You need an angle between the face and path (Spin Loft) and some force (speed) to create spin. No angle, no spin. No speed, no spin.

Nut a 5-iron, get a certain spin (rpm's). Nut it again, same everything except speed increases 10%. Spin would go up ROUGHLY 10%.

For illustration purposes only.....
 
Thanks. Now I kind of understand that spin loft is a part of other important calculations (in general terms). I can relate to backspin, not the spin loft with my limited Trackman knowledge.
 
Spin Loft is the loft responsible for SPIN!! (as implied from the name).
It is an intrinsic parameter for a club. It is the combination of the static loft on the clubhead and the loft imparted by the shaft on the clubhead at impact. In general, spin loft will be more than static loft.

(Ideally, this should be defined as dynamic loft, as this is the loft of the club head in motion and leave AA alone as defined by Dave Tutleman years before Trackman. But, Trackman has their own definition of dynamic loft and it is a bit confusing.)

The better way to remember is (using Trackman nomemclature)
Dynamic loft = Spin loft + AA (all assuming contact point is at the CG)
 
Spin Loft is the loft responsible for SPIN!! (as implied from the name).
It is an intrinsic parameter for a club. It is the combination of the static loft on the clubhead and the loft imparted by the shaft on the clubhead at impact. In general, spin loft will be more than static loft.

(Ideally, this should be defined as dynamic loft, as this is the loft of the club head in motion and leave AA alone as defined by Dave Tutleman years before Trackman. But, Trackman has their own definition of dynamic loft and it is a bit confusing.)

The better way to remember is (using Trackman nomemclature)
Dynamic loft = Spin loft + AA (all assuming contact point is at the CG)

If Spin Loft is an instrinsic parameter for a club, what don't they stamp the number on the botton of the driver like they do for Static Loft?

Does Tutleman have a term for where the face is pointing at impact?

You mentioned Tutleman's definition of AoA. What is it?
 
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If Spin Loft is an instrinsic parameter for a club, what don't they stamp the number on the botton of the driver like they do for Static Loft?

Spin loft as I said before has a contribution from the shaft at impact. The amount a shaft bends at or just before impact will depend on the golfer swing speed and their release.

Does Tutleman have a term for where the face is pointing at impact?

The same term that trackman uses

You mentioned Tutleman's definition of AoA. What is it?

I said about tutlemans's definition of dynamic loft and not about AoA. Sorry for not writing it clearly
 
Spin loft is the difference between AoA and dynamic loft. If you have a level strike and deliver 20 degrees of loft your spin loft is 20. If you hit up on the ball 5 degrees and deliver 20 degrees of dynamic loft your spin loft is 15 degrees. You can up up, level or down and not increase or decrease spin if this "spin loft" number stays the same. The only thing that would change with a center hit would be vertical launch angle.

If you hit down on it 5º instead of up 5 with a dynamic loft of 20º, the spin loft would 25º, right?
 
Spin loft is the difference between AoA and dynamic loft.

Actually, isn't Spin Loft the difference between the 3D face and 3D path? Therefore, anytime there is a differential between the horizontal path and face, the true Spin Loft will be larger than its vertical component (which is the difference between dynamic loft and AoA).

On that note, can anybody (smarter than myself) figure out what the formula would be to calculate True Spin Loft? For example, if there is a vertical differential of 20 degrees, and a horizontal differential of 5 degrees, the True Spin Loft should be somewhere between 20 and 25, but I'm not sure how to calculate that exactly...
 
Kevin -

When you use the word "clubhead direction" don't you mean "club path" and "angle of attack" together to make up
"clubhead direction"?
 
These are my alternate definitions. I feel that they clarify.

Dynamic Loft = the vertical angle of the clubface, relative to the ground, during impact.

Spin Loft = the vertical angle of the clubface, relative to the vertical direction that the clubhead is moving (Attack Angle), during impact.
 
In another thread, Brian goes on to correct my definition to what I posted above, which makes more sense.

Sorry Kevin, I gotta disagree with you. Spin Loft is not only a vertical measurement, rather an angular differential along the face of the D-Plane.

Vertical Face (Dynamic Loft) - Vertical Path (AoA) = "Vertical Differential"
Horizontal Face - Horizontal Path = Horizontal Differential
3D Face - 3D Path = Spin Loft
 
Was that thread of Brian's deleted? The one where he states "Compression = Spin Loft," is the one I'm looking for. I can't find it, even in my own old posts. Anyways, Brian goes on to talk about the additional calculation needed in addition to the vertical component of Spin Loft.
 
In another thread, Brian goes on to correct my definition to what I posted above, which makes more sense.

Sorry Kevin, I gotta disagree with you. Spin Loft is not only a vertical measurement, rather an angular differential along the face of the D-Plane.

Vertical Face (Dynamic Loft) - Vertical Path (AoA) = "Vertical Differential"
Horizontal Face - Horizontal Path = Horizontal Differential
3D Face - 3D Path = Spin Loft

No, this is wrong. Spinloft is the angular difference between two vertical components only, Attack Angle and Dynamic Loft. The horizontal components are not involved.
 
No, this is wrong. Spinloft is the angular difference between two vertical components only, Attack Angle and Dynamic Loft. The horizontal components are not involved.

This is my understanding of spin loft too - the difference between angle of attack and dynamic loft. I hope it's not more complex than that.
 
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