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Author Topic: asymmetry numbers  (Read 985 times)

J_w73

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asymmetry numbers
« on: January 05, 2010, 09:03:05 AM »
Is this the same as the intermediate differential.  What is the max allowed ??
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16-17 mph,350 rpm,PAP 5 1/2 x 3/8up, HighGame 300 x 4, High Series 808
Book Average 205,PBA Xperience ave180

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350 RPM, 17 MPH

 

J_Mac

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Re: asymmetry numbers
« Reply #1 on: January 05, 2010, 05:14:44 PM »
Define what you mean when you say "asymmetry numbers"

If I'm making the proper assumption, then yes, they are the same as intermediate differential.

There is not a maximum amount set since it has to fall inline with already established limits of RG.
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J_w73

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Re: asymmetry numbers
« Reply #2 on: January 05, 2010, 11:31:45 PM »
quote:
Define what you mean when you say "asymmetry numbers"

If I''m making the proper assumption, then yes, they are the same as intermediate differential.

There is not a maximum amount set since it has to fall inline with already established limits of RG.
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Bowlingballreviews.com... Gone, but not forgotten. Wayback Machine - http://www.archive.org/web/web.php

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16-17 mph,350 rpm,PAP 5 1/2 x 3/8up, HighGame 300 x 4, High Series 808
Book Average 205,PBA Xperience ave180

yes, that is what I am referring to.. what is considered a high or strong mb ??

Edited on 1/6/2010 0:53 AM
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350 RPM, 17 MPH

dizzyfugu

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Re: asymmetry numbers
« Reply #3 on: January 06, 2010, 04:05:26 AM »
It is relative. I think common consensus is that balls with an asym. RG diff. of 0.01" and more have a considerable mass bias that is worth taking into account when drilling the ball, and the current maximum is in the 0.03" range.

It is, technically, the difference between the core''s RG min and max at an axis 90° to the pin axis (sometimes referred to as Z axis).

There is not limit what''s allowed, but it is a measure of the inner weight distribution and the forces which occur when the ball/core rotates and wants to migrate towards its stable axis''. Therefore, the asym. RG diff. is always lower than the "normal" RG diff. - otherwise, I could imagine that you create negative flare or have a hard time controlling the core motion with the setup, esp. with strong pin/MB positions.

Biggest asym. Rg diff. number I have seen was a 0.042 for a "Black Test Ball" from Morich, used at USBC tests. Not sure if the ball was legal (I doubt it), but AFAIK the sky and the RG diff. are the limit.
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Edited on 1/6/2010 5:06 AM
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DizzyFugu ~ Reporting from Germany
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