Explaining bowling ball specs

[IHateTenPins]

I'm still learning about bowling balls and I want to see if I got this right. Low RG compared to High RG is when a ball hooks? So a low Rg ball hooks earlier than a high RG ball?


And differential is Hook potential?

[Mike White]

I'm still learning about bowling balls and I want to see if I got this right. Low RG compared to High RG is when a ball hooks? So a low Rg ball hooks earlier than a high RG ball?


And differential is Hook potential?

Low RG compared to High RG.

Low RG requires less torque to accelerate the angular velocity.

Translated: The ball revs up easier.

That means the lower RG ball STOPS hooking sooner, because when the rev rate matches the ball speed the ball quits hooking.

The ball needs friction to begin hooking, and that's all due to the surface of the ball.

The RG (high or low) has no effect on when the ball begins to hook.

Differential is related to flare potential.

That is connected to how quickly the ball will sense a significant increase in friction as it exits the oil pattern.

A ball with no flare will still be tracking along where there is oil on the surface of the ball when it has exited the oil pattern.

Some of that oil will be re-deposited onto the lane each revolution.

That re-depositing is the cause of carry down.

A ball that flares, but thrown before the oil is absorbed, (or wiped off) will cause more carry down than a non-flaring ball.

[ChuckR]

Doesn't the layout also modify the way the ball will react? a 40x4"x30 has a different result than a 65x5"x50 on the same ball and PAP.

[bowl1820]

RG: Radius Of Gyration.
The RG of a bowling ball tells you how soon the core is designed to roll.
A Low RG ball (aka: a Center Heavy ball) is easier to "rev up", rolls earlier and tends to mean earlier hook, more midlane reaction,a more evenly arcing ball used on wetter conditions.

A High RG ball (aka: a Cover Heavy ball) is harder to "rev up", rolls later and tends to mean later hook, more backend reaction, tends to be more angular.

The Low RG axis is the pin and the High RG axis is the PSA.
Total Diff = High RG - Low RG
Int Diff = High RG - Int RG


The RG Differential aka:The Differential:
Shows the difference between the low RG and the high RG.
The Differential indicates the potential for track flare.
The lower the differential the closer together the track flare rings are.
The higher the differential the further apart the track flare rings are.


Basic guide:
A lower RG ball with a low differential will produce an earlier rolling ball with a small arcing motion.
A lower RG ball with a high differential will produce an earlier rolling ball with a larger/stronger arcing motion.
A higher RG ball with a low differential will produce a later rolling ball with an angular backend motion.
A higher RG ball with a high differential will produce a later rolling ball with a strong, somewhat angular backend motion.

[djp1080]

Low RG compared to High RG.

Low RG requires less torque to accelerate the angular velocity.

Translated: The ball revs up easier.

That means the lower RG ball STOPS hooking sooner, because when the rev rate matches the ball speed the ball quits hooking.

The ball needs friction to begin hooking, and that's all due to the surface of the ball.

The RG (high or low) has no effect on when the ball begins to hook.

Differential is related to flare potential.

That is connected to how quickly the ball will sense a significant increase in friction as it exits the oil pattern.

A ball with no flare will still be tracking along where there is oil on the surface of the ball when it has exited the oil pattern.

Some of that oil will be re-deposited onto the lane each revolution.

That re-depositing is the cause of carry down.

A ball that flares, but thrown before the oil is absorbed, (or wiped off) will cause more carry down than a non-flaring ball.

Mike, I read your response and had to stop at line #4 where you're talking about rev rate matching ball speed.
What caused me to stop, was that rev rate is usually in revs per minute and ball speed is usually in feet per minute; therefore, they can never match.
I'm supposing that there is some magic ratio in values if you're using revs/min and feet/min as your units. What is that magic ratio that you might be referring to???

Thanks...

[Mike White]

Mike, I read your response and had to stop at line #4 where you're talking about rev rate matching ball speed.
What caused me to stop, was that rev rate is usually in revs per minute and ball speed is usually in feet per minute; therefore, they can never match.
I'm supposing that there is some magic ratio in values if you're using revs/min and feet/min as your units. What is that magic ratio that you might be referring to???

Thanks...

1 mile = 5280 feet = 63,360 inches.

The circumfrence of a ball is about 27 inches, (effectively less as you increase axis tilt)

63,360 / 60 (convert to minutes) / 27 (convert to revolutions) = 39.111

A ball rolling 1 mph, will have a rev rate of 39.111 rpm

When you release the ball, it will most likely have more forward speed than equivalent rev rate.

The ball senses friction from the lane causing it to slow down, but since the direction of the friction force is not directly thru the center of the ball, it causes an increase in rev rate.

The best analogy is an airplane tire when it's landing, before contact the wheel isn't spinning as fast as the plane is traveling forward.

When it does make contact, friction causes the wheel to increase it's rev rate until it matches the planes speed.

Take whatever speed the ball is at as it enters the pins, multiply by 39.111, and you have a good estimate of the rev rate as it enters the pins.

This of course assume you threw the ball in a way that it will roll before hitting the pins.

[fordman1]

Mike you should not use about and assuming when talking like the guy in the wheel chair who has an iq of 227.

[Mike White]

Doesn't the layout also modify the way the ball will react? a 40x4"x30 has a different result than a 65x5"x50 on the same ball and PAP.

Layout modifies the resulting RG of the PAP, and modifies the amount of flare possible.

If you put the pin on the PAP, you get no flare, just like if you put the pin 6 3/4" from the PAP.

Drilling angle 40 vs 65 has no effect on a symmetrical ball.

Val Angle can increase or decrease the differential depending on the angle.

Smaller would increase.

The practical limits for val angle are to avoid tracking over the holes.

[Mike White]

Mike you should not use about and assuming when talking like the guy in the wheel chair who has an iq of 227.

I used the word "about" because not all balls have a maximum circumference of 27" due to being resurfaced, and as you increase tilt, the ball will need a higher rpm compared to mph when rolling.

I used the word "assume", because most shots that are thrown completely in the oil are not rolling when contacting the pins, and therefore mph * 39.111 wouldn't give a good estimation of rpm.

[IHateTenPins]

Thanks everyone for their explanations, I think I understand it better now and it'll help me with my next ball purchase.