Spin-to-Speed or Revolutions-per-Foot?

I've never thought about inhaling or exhaling during my stroke.
You never used to....

Screenshot 2026-02-18 154732.png
 
I can’t find it. But in some video somewhere, probably buried in a podcast, Tyler Styler talks about spin to speed ratio and how trying to increase it has helped him make pockets bigger. So there is real world discussion about this subject.

Efren plays with a high spin to speed ratio.

Whether or not it helps you at all in your own game, it could be a neat statistic to place next to pro players.

You can actually track this over time with the DigiBall, though you need to export the data and do your own statistics in Excel.
 
I can’t find it. But in some video somewhere, probably buried in a podcast, Tyler Styler talks about spin to speed ratio and how trying to increase it has helped him make pockets bigger. So there is real world discussion about this subject.
If only it helped him in the Mosconi Cup. His spin to speed ratio must've been way off on those couple 9 balls.
He should've studied these equations more.
 
After I said this, I exported 10 minutes of DigiBall data and calculated that my SPF was an average of 1.326, with a standard deviation of 0.506.

I think this is useless, lol.

It would only have meaning if you could compare it to, say Jayson Shaw, running 500+ balls, and maybe noting you aren't using as much spin as he is. Maybe using less could help, for 14.1.

It would have to be very specific for it to matter.
 
RPF definitely increases linearly with tip offset. The math and physics is here:


where SRF is the spin-rate factor (spin-to-speed ratio), omega is the angular speed in radians/sec, v is the ball speed, R is the ball radius, and b is the tip offset from center.

Speed is related to distance (d) and time (t):
v = d / t​
So:
SRF = (omega * t) * R / d​
The first term is related to revolutions (rev) according to:

(omega * t) = rev * (2 * pi) [there are 2*pi radians per revolution]​
So:
SRF = (2 * pi * rev) * R / d​
So revolutions per foot (RPF) is:
RPF = rev / d = SRF / (2 * pi * R)​
with d and R measured in feet.

The ball radius (in feet) is:
R = (2.25" / 2) * (1ft / 12") = 1.125/12 feet​

For an assumed maximum spin at the standard miscue limit of 0.5*R,

SPF = (5/2) * (b/R) = (2.5) * (0.5) = 1.25​
which gives:
RPF = 1.25 / (2 * pi * 1.125/12) = 2.1 rev/ft
If you roll a ball (SRF = 1) and see how many revolutions it makes in one foot, you would observe:

RPF = 1 / (2 * pi * R) = 1.7 rev/ft​

Well, that sure cleared it up.

Lou Figueroa
 
After I said this, I exported 10 minutes of DigiBall data and calculated that my SPF was an average of 1.326, with a standard deviation of 0.506.

I think this is useless, lol.

It would only have meaning if you could compare it to, say Jayson Shaw, running 500+ balls, and maybe noting you aren't using as much spin as he is. Maybe using less could help, for 14.1.

It would have to be very specific for it to matter.
I think everything you can learn about the game adds to your skills, even if you don't notice it. For instance, a more familiar way of expressing the amount of spin on the CB might make it easier and more accurate to visualize/predict the effects, even subconsciously.

And just to be clear about "analysis paralysis"... of course nobody suggests doing anything more than the simplest of estimations while playing - details like this increase/improve the base knowledge on which your "intuitive" game is built and grows.

pj
chgo
 
I think everything you can learn about the game adds to your skills, even if you don't notice it. For instance, a more familiar way of expressing the amount of spin on the CB might make it easier and more accurate to visualize/predict the effects, even subconsciously.

And just to be clear about "analysis paralysis"... of course nobody suggests doing anything more than the simplest of estimations while playing - details like this increase/improve the base knowledge on which your "intuitive" game is built and grows.

pj
chgo
If retaining useless information like this actually equated to improved ability/skill, then we'd all be 800 Fargo.

Just hit a million balls bro.

However, I do think it can help instructors when teaching players who are interested in these kind of things and showing how physics apply to real life scenarios on the table.

As a sole player, I am never thinking about spin to speed ratio when I'm about to shoot or down on a shot, I think of:

What aim do I need?
What spin do I need?
What speed do I need?

ASS
 
If retaining useless information like this actually equated to improved ability/skill, then we'd all be 800 Fargo.
Except for you, apparently.

Just hit a million balls bro.
Of course - but I'll do it with as much knowledge and understanding as possible.

I do think it can help instructors when teaching players who are interested in these kind of things and showing how physics apply to real life scenarios on the table.
Sure - even if you learn it yourself.

As a sole player, I am never thinking about spin to speed ratio when I'm about to shoot or down on a shot, I think of:

What aim do I need?
What spin do I need?
What speed do I need?
And knowing about spin to speed helps your understanding of and ability to produce those answers accurately.

Yep, knowledge can improve your ability to quickly/accurately determine the right Angle/Spot/Speed.

But of course, if knowledge isn't your thing... maybe 2 million balls?

pj
chgo
 
After I said this, I exported 10 minutes of DigiBall data and calculated that my SPF was an average of 1.326, with a standard deviation of 0.506.

I think this is useless, lol.

It would only have meaning if you could compare it to, say Jayson Shaw, running 500+ balls, and maybe noting you aren't using as much spin as he is. Maybe using less could help, for 14.1.

It would have to be very specific for it to matter.
One place where it might be interesting is on the one-pocket break shot. I try to achieve a high rate of spin (max outside) and very little speed to get the ball into the pack, off the rail, and back to that second diamond sitting on the rail....
 
But of course, if knowledge isn't your thing... maybe 2 million balls?

pj
chgo
I do enjoy some good knowledge, physics and math were my favorite subjects in school.

But as it pertains to pool, I think a basic understanding is good enough. I try not to incorporate all these fine details into my gameplay. It is more about execution for me. You're literally over-thinking it.

But everyone is different. We're not all pool nerds like you. I can appreciate Dr. Dave's videos because he is actually accredited in physics and presents information in a digestible manner (at least on YouTube).
Your ramblings just put me to sleep.

I don't understand why you have to resort to passive-aggressive remarks when we're having civil discourse.
 
One place where it might be interesting is on the one-pocket break shot. I try to achieve a high rate of spin (max outside) and very little speed to get the ball into the pack, off the rail, and back to that second diamond sitting on the rail....
Hmmmm. Very interesting
 
I think that the reasons for even analyzing pool in the first place is to
1. Separate the myths from reality by using science and observation (which by the way is how myths and reality are separated from each other in any subject except religion)
2. Focus on understanding reality
3. Applying your understanding by practicing on the boundaries of your knowledge as to expand those boundaries
4. Do extra work in order to condition your body and mind
5. Execute peacefully and organically through trust in your previous training.

The HAMB people only focus on number 5 their entire pool careers.

Training, really learning, for anything, can be broken apart, instead of inefficiently digested all at once, all of the time.

Spin to speed ratio, diamond systems, brainwash drills thought patterns, etc all are not to be thought of during performance, just during practice when you have time to develop.
 
One place where it might be interesting is on the one-pocket break shot. I try to achieve a high rate of spin (max outside) and very little speed to get the ball into the pack, off the rail, and back to that second diamond sitting on the rail....
Outside spin on One Pocket break? I did not know that.
 
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