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Author Topic: low rg and high diff question...  (Read 56746 times)

lefty50

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low rg and high diff question...
« on: July 07, 2015, 06:38:18 PM »
current specs.. Left hand, 250 rev, 16.5 off the hand, high axis rotation.

the following is primarily, but not totally, a med-hvy oil and up scenario question.

Several years ago I was told by members on this forum whom I trust that with my style of bowling (low rev, high rotation), I would always want a low RG high differential ball. That did and still does make sense to me since my favorite ball at the time was a storm Special Agent. I've always done well with high diff symmetrical balls, which makes sense. Any ball with a high RG lopes down the lane too long and never gets into a roll. Low differential ball are pretty much the same.

It seems to me that these days the vast majority of balls are higher RG and lower differential, but yet they are advertised as big hook balls, which flies in the face of what my style encounters in real life. The answer is either that they are no longer making the type of ball I prefer (few exceptions) or that the cover stock is so dramatically different that I no longer have the low RG high differential qualification requirement.

I should add that I have had nothing but trouble with asymmetric and will only buy symmetric from now on. I know that there are few balls out there like the Motiv Covert Revolt, but there are many others I would like to try based on their rating to give me some help in the rev department, but I just can't see a .047 or so low rg ball revving enough for me.

Which is true?
Thanks in advance

 

JustRico

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Re: low rg and high diff question...
« Reply #46 on: July 15, 2015, 07:00:12 PM »
Thank you
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tommygn

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Re: low rg and high diff question...
« Reply #47 on: July 16, 2015, 08:33:00 AM »
If you are going to argue that my example is a "flawed" experiment noting that the core shapes are only similar in numbers but ultimately different, then you are saying that core shape matters in the equation. If core shape matters in any factor of the equation, given your argument with me, we measure the core relation after construction of the ball with the x y and z axis and the differences of them, and show that in Rg and differential (and sometimes intermediate differential) to quantify the core with numbers. The thing is, I can look at a core shape and get a rough idea of it's characteristics based on symmetry and comparing to previously released balls with similar characteristics, but what I CAN'T see, is the density of that said core, or see what materials were used to construct the core. I can't see how dense a flip block is, I can't see how dense the main body of the core is compared to the flip blocks, or be able to tell how much it weighs by looking at it. The weight of the core will also determine the amount and density of filler material needed to create a desired weight of a ball. Rg helps give us an idea of the core being very center heavy or being cover heavy. So, since my test is "flawed" because of it using two different cored balls, and Rg is one of the telling factors of the density of core to filler material to cover weight of a ball, then Rg matters, because it shows the numerical differences of different cores.
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bergman

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Re: low rg and high diff question...
« Reply #48 on: July 16, 2015, 02:52:26 PM »
A few years ago, the USBC did an intensive study into the factors affecting ball motion. They concluded that the 3 biggest factors were in order: coefficient of friction,
ball oil absorption rate and Rg. Core differentials, although a factor, were determined to be not as much an influence as the first three.

Although I tend to agree in general with this study based on my own experiences, I
disagree with Rg alone, as being a determining factor. Instead, I believe that a ball's "moment of inertia" to be a more deciding factor than Rg . It's that quantity that determines a ball's ability to "rev up" (or, in keeping with the physics, the ball's
ability to resist angular acceleration).  Rg alone is simply a measurement of the distance of a center of (rotating) mass from an axis. If the mass increases but the distance remains the same, you increase the moment of inertia, making the ball harder to "rev-up" and vice versa. Rg is one component but it is not the only one.
If the mass remains the same, but its distance from its axis changes, then the ball's moment of inertia will change affecting the ball's ability to rotate. The mass value
needs to be known as well.


 

tommygn

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Re: low rg and high diff question...
« Reply #49 on: July 17, 2015, 10:13:24 AM »
Interesting you brought up the ball motion study, bergman. Always makes for a good read:

http://www.bowl.com/uploadedFiles/Equip_and_Specs/Equip_and_Specs_Home/08ballmotionstudy.pdf

God creates us with a blank canvas, and the "picture" we paint is up to us. Paint a picture you like and love!

JustRico

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Re: low rg and high diff question...
« Reply #50 on: July 17, 2015, 11:32:41 AM »
Waste of a million dollars
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BradleyInIrving

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Re: low rg and high diff question...
« Reply #51 on: July 17, 2015, 06:34:06 PM »
Lefty50, I'm throwing this out there but I'm sure you already understand and know, but take any ball.... For example, a  ball that's 2.55 high rg,  2.50 low rg which gives it a .050 differential.... Now, by putting the pin on your axis that's the ball's low rg and the more you raise it to 6 3/4" from your PaP it would be 2.55...

BradleyInIrving

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Re: low rg and high diff question...
« Reply #52 on: July 17, 2015, 06:35:01 PM »
The point I'm making is that you can take any ball and drill it to make it work :)

JustRico

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Re: low rg and high diff question...
« Reply #53 on: July 17, 2015, 06:42:32 PM »
All I know is he has a horse in his backyard that is extremely beat...yet still dead
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kidlost2000

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Re: low rg and high diff question...
« Reply #54 on: July 17, 2015, 06:43:13 PM »
Brad don't bring that logic to a forum
…… you can't  add a physics term to a bowling term and expect it to mean something.

kidlost2000

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Re: low rg and high diff question...
« Reply #55 on: July 17, 2015, 06:43:49 PM »
All I know is he has a horse in his backyard that is extremely beat...yet still dead


No pond I bet
…… you can't  add a physics term to a bowling term and expect it to mean something.

BradleyInIrving

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Re: low rg and high diff question...
« Reply #56 on: July 17, 2015, 08:07:13 PM »
Ric and Kid -- lol ;)

tommygn

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Re: low rg and high diff question...
« Reply #57 on: July 20, 2015, 09:30:47 AM »
The point I'm making is that you can take any ball and drill it to make it work :)


Lefty50, I'm throwing this out there but I'm sure you already understand and know, but take any ball.... For example, a  ball that's 2.55 high rg,  2.50 low rg which gives it a .050 differential.... Now, by putting the pin on your axis that's the ball's low rg and the more you raise it to 6 3/4" from your PaP it would be 2.55...



Maybe you can kind of get lucky with that working on over walled house conditions that are set up for as many styles and rev rates to still be able to score, but on competitive patterns, it isn't that simple. If it were that simple across the board, I highly doubt ball companies would spend the kind of money they do on R&D of core shapes and densities of said cores.
God creates us with a blank canvas, and the "picture" we paint is up to us. Paint a picture you like and love!

tommygn

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Re: low rg and high diff question...
« Reply #58 on: July 20, 2015, 09:32:14 AM »
All I know is he has a horse in his backyard that is extremely beat...yet still dead

So if someone doesn't agree with you, they are beating a dead horse? Got it.
God creates us with a blank canvas, and the "picture" we paint is up to us. Paint a picture you like and love!

lefty50

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Re: low rg and high diff question...
« Reply #59 on: July 20, 2015, 09:54:44 AM »
I just came back and was amused to see this thread still alive. I haven't read thru it and don't intend to, but I did read the last few... Ric, you just never shut up, do you? Your arrogance is fascinating, but boring. My whole point was that despite what numbers say, I cannot deny what my eyes see. The next logical step in the process is to research why. Hence, the question. I should have known better. that's why myself and others just don't come here any more... Previous studies can be a waste of money, but Ric's right... God man, get over yourself.
(Shaking his head, he departs again).

JustRico

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Re: low rg and high diff question...
« Reply #60 on: July 20, 2015, 09:58:39 AM »
I'm not sure how you're not employed in the industry somehow with your vast knowledge and input....I'm arrogant wow
Co-author of BowlTec's END GAMES ~ A Bowler's COMPLETE Guide to Bowling; Head Games ~ the MENTAL approach to bowling (and sports) & (r)eVolve
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