I hit 100 golf wedge shots with a launch monitor running.
Let's see what I found out 👇👇👇
Bookmark📚 this monster thread 🧵
For the test, I hit shots from 2 different lies indoors.
🔵Grass - simulated lie (fiberbuilt bristles) which would simulate having a perfect lie with a big cushion beneath the ball
🔴Normal range mat - tight and firm - like a hardpan lie but a bit more spongy
Shots were
▪️40 yards
▪️45 deg dynamic loft (yellow arrow)
▪️8 deg attack angle (white line)
▪️53 deg spin loft (pink shaded area)
All had very tight standard deviations
This is a visual of the average spin rates for the different vertical face strikes for the GRASS lie
This is a visual of the average spin rates for the different vertical face strikes for the TIGHT lie
And, for easier comparison, here they are side by side
And here's a charted visual of the data
Why does spin rate get lower as the strike goes up the face?
In these examples..
It's NOT gear effect - irons have little to no gear effect
It's NOT debris - no mud/water on the mats
The answer is.....
Something I call DYNAMIC SPIN LOFT
While a launch monitor often shows the data (attack angle, loft, spin loft) WITHOUT the club-ball collision, this collision matters.
You see, as the clubhead is in contact with the ball, it gets deflected down by the force of the ball (yellow)
Dave Tutelman calls this "Newton's Divot"- it can explain how someone can have a divot after the ball even with a slightly positive attack angle
When we strike low on the face, the club interacts with the turf late (pink star)
It's free to be deflected down more - increasing spin loft
However, when we hit higher on the face, we're essentially interacting with the turf further back
This gives more time for the club attack angle to deflect "less down", changing DYNAMIC SPIN LOFT (through the ball)
This is why higher strikes correlated with lower spin rates
- more deflection through impact
- thus lower dynamic spin loft
- thus lower spin
But why such a difference between lies?
Well, on the
🔵Grass lie, interaction with the ground is always farther forwards + softer. Meaning less time to deflect the attack angle, and by a lesser amount
🔴Tight lie, interaction with the turf is much earlier and more violent, meaning bigger dynamic spin loft changes
We can see this visualized here
Lie with grass cushion beneath it with predicted attack angle (green)
vs deflected (yellow)
Then the exact same swing and strike but from a tight lie - earlier deflection
This is also why you see launch angle increase more rapidly for the tight lie
The increase in upward deflection of the clubhead "bouncing" off the turf created a more variable and higher launch angle
Not only was
▪️Spin lower
▪️launch higher
For the tight lie, but it also had more variability to those factors.
This resulted in more distance per mph of club speed, and more variability in distance (or less distance control)
For reference,
-20 to -10mm is low on the face but functional
-10 to 0 is fatter contact, but not awful (pro fat)
What this means for you???
More research needs to be done from varying lies, with real grass too, and at different spin lofts.
But this study shows
✅The "bounce up" effect that can occur when the club interacts with the ground too early
✅Hard-pan, range mats or similar lies will give higher launch and lower spin, often resulting in more distance
✅Even similar launch-monitor-reported spin-lofts can produce very different launch and spin characteristics
✅It may be harder to control distance from tight, hardpan lies - even if contact is cleaner (no grass)
✅Bounce may not always be your friend - in some cases it may be the thing that creates less consistent spin/launch/distance control
✅Explains those low-nipped wedge shots that spin more when you catch the bottom groove
✅Striking more towards the bottom of the club (as long as not bladed) will give more consistent distances from varying lies
What else did you get from this data?
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