With a much larger thumb hole, I'm sure it changes the dynamics of the ball in some way. But, I'm not sure exactly how. I'm assuming some balls gain more and/or less flare ??

Thanks

it sure does change the dynamics

For what its worth, and to support the info found in the study, I recently converted my Raptor Talon from a normal 1 1/4" slug to an IT 1 1/4...zero difference in reaction whatsoever.

Matt

I believe the ball manufacturers have taken the issue into consideration as they design their cores.  If you have an older ball you may (or may not) remove enough mass to effect reaction.  Each ball would be different based on layout and it's individual core design.

It was about 4 - 5 years ago (when changeable inserts were new to the market) Brunswick had a few returns on a certain ball.  I can't remember which one, but as they tested "why" it was determined that with a certain layout, etc., enough mass was removed to adversely effect the reaction.  Most balls were fine, but now they had to plan for this possibility.

They immediately started tweaking things to accommodate the extra mass removed by drilling so deep and large a thumb hole.  I would bet that every major manufacturer has taken similar steps.

I would not disagree with the above mentioned study, but no study could possibly test every possible ball and layout options.  The study can only report on the balls it tested and not on the ones it didn't...

I thought it would affect reaction, and maybe it does, in some tiny way I'm not good enough to notice, because the way I look at it, I'm drilling a 1 5/16 hole 3 1/2" deep...if that doesn't affect reaction then how do weight holes that are a lot of times smaller?

One thing to remember is that after you drill the hole, your adding mass/weight back into the hole when you put the interchangable into the slot. So theres not that big of a change in the mass/weight

As for the weight hole your not putting anything back into it, also the location plays a big part with it.

Plus they didn't say it didn't change anything, just that the change was so small. it didn't make a difference.

Quote from: Matt Fortney on November 14, 2013, 03:38:35 PM

I thought it would affect reaction, and maybe it does, in some tiny way I'm not good enough to notice, because the way I look at it, I'm drilling a 1 5/16 hole 3 1/2" deep...if that doesn't affect reaction then how do weight holes that are a lot of times smaller?

One thing to remember is that after you drill the hole, your adding mass/weight back into the hole when you put the interchangable into the slot. So theres not that big of a change in the mass/weight

As for the weight hole your not putting anything back into it, also the location plays a big part with it.

Plus they didn't say it didn't change anything, just that the change was so small. it didn't make a difference.

Not exactly.  According to your first post, the study merely said that the difference in ball dynamics were within one standard deviation.  Presumably, this is based on a mean difference of zero (which is the hypothesis being tested).  However, depending on how large the standard deviation is, even a statistically insignificant difference of one standard deviation (presumably plus or minus) can translate into a significant difference on the lane.  Do you have a link to the USBC study so that we can see the results?

Bob

To say that a very large and deep thumb hole that changes the shape of the core doesn't change ball motion, but a balance hole placed in the P1, P2, P3 ,or P4 position, and DOES change reaction, is complete contradiction. I will say this. ANY hole in a bowling ball will affect it. It may not change the ball enough to see a noticeable difference, but it will change it none-the less. To what degree of noticeable change of ball motion would be based on the style of the bowler.

https://www.buddiesproshop.com/images/Drill_Sheets/Gradient_line_balance_hole.pdf