Author Topic: low rg and high diff question... (Read 56594 times)

lefty50 · « **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

BackToBasics · « **Reply #16 on:** July 09, 2015, 08:33:29 AM »

Quote from: lefty50 on July 08, 2015, 12:25:30 PM

I appreciate all the expertise, but frankly, I side with those on the board who have all said frequently that although it may not seem to matter, it clearly does when we see the evidence of our own eyes. Evidence must be examined, not thrown aside, and I've seen Rg matter too often to deny my own experience.
Oh good grief, I give up. Why do I even post here... ? Sigh...

So let me get this straight. You post a question based on your preconceived notions and then get upset when all of the answers aren't what you wanted to hear?

LookingForALeftyWall · « **Reply #17 on:** July 09, 2015, 09:22:50 AM »

As a lefty with somewhat similar stats, I think I understand lefty50's frustration. I too feel that as a high rotation/low rev lefty that I have a high sensitivity to higher RG's and lower Diffs. However I do not have an aversion to using asymmetric balls on heavier patterns.

lefty50, have you tried different layouts on asymmetric balls? Why are asymmetric balls out of the question?

spmcgivern · « **Reply #18 on:** July 09, 2015, 01:46:24 PM »

I guess I can't leave well enough alone....

lefty50, am I understanding it right that your experience has shown you that the difference between a low Rg core ball and a high Rg ball (pre-drilled) is noticeable to you?

Because I find it hard to believe it is the pre-drilled Rg that is the deciding factor in what you see. If we look at Storm as an example, the difference between their lowest Rg and highest Rg core is (2.58-2.48) or 0.1 inches. Motiv is 2.59-2.46=0.13. Brunswick is 2.578-2.487=0.091.

Also, it is almost universal across all brands that high Rg cored balls are in the lighter oil parts of the line-up while lower Rg cored balls are in the heavier oil parts of the line-up. Usually matched up with weaker coverstocks. Perhaps part of what you are seeing is more related to coverstock differences than pre-drilled Rg differences.

Also, it is almost universal across all brands that high Rg cored balls have smaller differentials than low Rg cored balls. Perhaps you are seeing a difference in differential instead of pre-drilled Rg differences.

tommygn · « **Reply #19 on:** July 14, 2015, 02:31:36 PM »

Here are two balls with the same cover, same differential, same cover prep, and same layout; only difference being the Rg, definitely go through the back part of the lane and through the pins differently for me.

http://stormbowling.com/products/balls/skyrocket

http://stormbowling.com/products/balls/hyroadpearl

Same can be said for these two balls as well. I never could get the Hyroad to roll as good as what everyone else did and frankly was very frustrating for me to watch everyone and their brother throw this ball and it look so great when I had dart or dive with it except for rare occasions, but that "subtle change" to the core Rg has made it near impossible for me to put down the Rocket, and give me a ball that I throw a lot.

http://stormbowling.com/products/balls/rocket

http://stormbowling.com/products/balls/hy-road

No extra holes used that would reshape the cores.

spmcgivern · « **Reply #20 on:** July 14, 2015, 02:48:13 PM »

tommygn,

I wonder how much core shape along with axis migration plays in what you are seeing.

Also, I personally feel that even though they both have R2S pearl, Storm has changed the formula over the years to match the current state of oils. R2S has been the Thunder line coverstock for a while and I think they change the formula ever so slightly to keep it relevant.

tommygn · « **Reply #21 on:** July 14, 2015, 03:17:43 PM »

It has to do with physics and moment of inertia. A higher Rg has a greater distance of the mass to the rotating axis thus a slower spin time, compared to more center heavy mass, which has a shorter distance from mass to the rotating axis.

A Higher Rg will spin slower with same torque applied compared to a lower Rg.

JustRico · « **Reply #22 on:** July 14, 2015, 03:23:38 PM »

What exactly is the difference in the RG

tommygn · « **Reply #23 on:** July 14, 2015, 03:38:20 PM »

Quote from: JustRico on July 14, 2015, 03:23:38 PM

What exactly is the difference in the RG

.03, which apparently is enough of a difference to allow me to miss in and either strike or leave something make - able, compared to missing in and leaving a 3-7-9 because the ball comes in behind the head pin too much.

spmcgivern · « **Reply #24 on:** July 14, 2015, 04:33:35 PM »

Quote from: tommygn on July 14, 2015, 03:17:43 PM

It has to do with physics and moment of inertia. A higher Rg has a greater distance of the mass to the rotating axis thus a slower spin time, compared to more center heavy mass, which has a shorter distance from mass to the rotating axis.

A Higher Rg will spin slower with same torque applied compared to a lower Rg.

I understand the physics of it, but those theories are based on the moment of release. Once friction is encountered then Rg should become less of a factor up until the ball rolls out. At that time Rg is meaningless.

JustRico · « **Reply #25 on:** July 14, 2015, 04:39:47 PM »

Sorry I can dispute your case as easily as you can defend it
Unless it the exact same bowling ball with a core differing by .03 in RG too many variables
And trust me I understand MOI as well as coefficient of restitution which is an effect also
If you feel 3/100,000 of inch matters great...I don't

tburky · « **Reply #26 on:** July 14, 2015, 05:02:37 PM »

3/100 of an inch

JustRico · « **Reply #27 on:** July 14, 2015, 05:44:15 PM »

Thank you miss comma

BackToBasics · « **Reply #28 on:** July 14, 2015, 09:05:19 PM »

Quote from: tommygn on July 14, 2015, 02:31:36 PM

Here are two balls with the same cover, same differential, same cover prep, and same layout; only difference being the Rg, definitely go through the back part of the lane and through the pins differently for me.

http://stormbowling.com/products/balls/skyrocket

http://stormbowling.com/products/balls/hyroadpearl

Same can be said for these two balls as well. I never could get the Hyroad to roll as good as what everyone else did and frankly was very frustrating for me to watch everyone and their brother throw this ball and it look so great when I had dart or dive with it except for rare occasions, but that "subtle change" to the core Rg has made it near impossible for me to put down the Rocket, and give me a ball that I throw a lot.

http://stormbowling.com/products/balls/rocket

http://stormbowling.com/products/balls/hy-road

No extra holes used that would reshape the cores.

The obvious, and biggest flaw is that these are not the same balls with just the RG being different. Core shapes and densities make a difference as the ending ball after being drilled will have different specs.

You need to compare the exact same ball and core with only the low RG being different.

tburky · « **Reply #29 on:** July 14, 2015, 11:30:21 PM »

Quote from: JustRico on July 14, 2015, 05:44:15 PM

Thank you miss comma

your welcome

tommygn · « **Reply #30 on:** July 15, 2015, 07:32:16 AM »

Quote from: BackToBasics on July 14, 2015, 09:05:19 PM

Quote from: tommygn on July 14, 2015, 02:31:36 PM
Here are two balls with the same cover, same differential, same cover prep, and same layout; only difference being the Rg, definitely go through the back part of the lane and through the pins differently for me.

http://stormbowling.com/products/balls/skyrocket

http://stormbowling.com/products/balls/hyroadpearl

Same can be said for these two balls as well. I never could get the Hyroad to roll as good as what everyone else did and frankly was very frustrating for me to watch everyone and their brother throw this ball and it look so great when I had dart or dive with it except for rare occasions, but that "subtle change" to the core Rg has made it near impossible for me to put down the Rocket, and give me a ball that I throw a lot.

http://stormbowling.com/products/balls/rocket

http://stormbowling.com/products/balls/hy-road

No extra holes used that would reshape the cores.

The obvious, and biggest flaw is that these are not the same balls with just the RG being different. Core shapes and densities make a difference as the ending ball after being drilled will have different specs.

You need to compare the exact same ball and core with only the low RG being different.

Oh really?

Then please explain to me how you change the radius of gyration of an object, without altering the object in any way.

Author Topic: low rg and high diff question... (Read 56594 times)

lefty50

low rg and high diff question...

BackToBasics

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LookingForALeftyWall

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spmcgivern

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tommygn

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spmcgivern

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tommygn

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JustRico

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tommygn

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spmcgivern

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JustRico

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tburky

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JustRico

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BackToBasics

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tburky

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tommygn

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