# Bowling Ball Release Ratio

Duration: 1:49

One of the key components of understanding ball motion for a bowler is what Rod Ross calls a bowling ball release ratio. This is a ratio of how fast the ball is traveling down a lane in relation to how fast the ball is spinning. See an example of how a release ratio works and how to use this trick to your advantage.

6 Responses to “Bowling Ball Release Ratio”
1. gundy

If the bottom number is how fast the ball is spinning, shouldn’t it be in terms of revolutions (as opposed to 7mph as stated in the video) How can you identify 7 mph spinning????

• Customer Service Techs

Agreed, it would be very difficult to visually identify a specific speed such as 7mph. Revolutions need to be converted to mph so that the ratio uses the same units of measure, in our case (MPH). RPM’s (Revolutions Per Minute) are what’s visibly measureable from a bowler’s release. By finding the bowlers PAP (positive axis point) and taping the ball from the PAP to above the finger holes the RPM can be visually measured and calculated. To calculate the release ratio and display it accurately, both travel speed and spin speed need to be in the same units (MPH). To calculate RPM’s to MPH the following formula is used: There are a lot of unit conversions to get to the familiar miles per hour. Cancelling units, And simplifying we arrive at: Where the Rev Rate is in RPM and the Radius is in inches. For a Radius of 4.27 inches and a rev rate of 300 RPM, the speed of the outer shell due to rotation is approximately 7.62 MPH.

• Customer Service Techs

Thank you for your question. It would be very difficult to visually identify a specific speed such as 7mph, therefore we need to calculate MPH (Miles Per Hour) from RPM’s (Revolutions Per Minute). RPM’s need to be converted to MPH so that the ratio uses the same units of measure, in our case MPH.
RPM’s are what’s visibly measureable from a bowler’s release. By finding the bowlers PAP (positive axis point) and taping the ball from the PAP to above the finger holes the RPM’s can be visually measured and calculated. To calculate the release ratio and display it accurately, both travel speed and spin speed need to be in the same units, MPH.
To calculate RPM’s to MPH the following formula is used:
There are a lot of unit conversions to get to the familiar (MPH) miles per hour.
Cancelling units,
And simplifying we arrive at:
Where the Rev Rate is in RPM and the Radius is in inches. For a Radius of 4.27 inches and a rev rate of 300 RPM, the speed of the outer shell due to rotation is approximately 7.62 MPH.

2. Leif Espen

Hi, what is the matching up ratio? if you are trowing it at a higher speed, you have to create more rpm`s. At lower speed, less rpm`s. to get the matching up ratio between speed and rpm`s.how to practical use this? Other than reduce speed, tilt axis and rpm. to match up to the friction/oil. is there a specific ratio that is ideal?

• Customer Service Techs

Hi,

The ratio is a measurement of how fast the ball is traveling vs. how fast it is spinning. Matching up depends on the environment you’re bowling on including lane pattern, lane topography, and how the pattern breaks down. The application of the ratio can help determine if #1 the bowlers normal ball speed and RPM’s are an effective match, #2 ball speed should be increased or decreased, and #3 if RPM’s should be increased or decreased.

Ratios between 1.5 and 2.5 seem to be the most effective and players who can change their ratio to fit the environment (lane pattern, transition) tend to perform better.

Thanks for question and for continuing with the USBC Bowling Academy.