In the 'Basic Top Weight Question' thread, it appears it was generally agreed upon that static weights have minimal to no effect on ball performance.  If this is the case then how does drilling a ball 'pin up' vs. 'pin down' affect ball motion?  Having the pin above the fingers or below does not affect radius of gyration, the only affects would be on the location of the bowties and static weights(i.e. finger or thumb weight).  The ending static weights would also be dependent upon pin to CG distance and weight removal during drilling.  I'm not aware of any way that drilling a ball 'pin down' can make it 'early revving' unless the final statics are  thumbweighted, or if the pin is less than 3 3/8 inches from the PAP and 'pin down'.

How physically does placing the pin 'up' vs. 'down' change Radius of Gyration Differential, and to what amount would this effect be?  RG Differential is the difference between the RG of the ball with the core parallel the one's axis vs. the RG of the ball with the core perpendicular to ones axis.  This difference is manufactured into the ball, and other than drilling holes into the ball I don't see how this difference can be changed.

I think a better way to look at this is:

1.  Look at all aspects of a bowling ball before drilling.  Mainly, look at the core and see its orientation in the ball.

2.  Look at the core numbers to get an idea of how much affect the core may have on ball dynamics.  (big core or little core, low RG or high RG, etc...)

3.  Now, imagine drilling holes (pin up) in the ball and taking out chunks of the core.  The core is more dense than any other part of the ball and changing its shape and mass will have the largest affect on ball dynamics.

4.  Evaluate the ball with the holes in the ball and imagine the change in the core dynamics.

5.  Go to step 3 and re-imagine with a different drilling (pin down).  Repeat as much as necessary.

The thing to consider is the holes you are drilling into the ball change the core dynamics.  I am sure everyone agrees the ball's core statistics are not the same after drilling.  Depending on where you put the holes, how big the holes and how deep the holes will change the dynamics from either a little bit to a whole bunch.

The pin up drilling will take a little of the core at the top of the ball with the fingers (small holes drilled shallow) and more of the center of the core out with the larger and deeper thumb hole.  This looks to me like it should "increase" the RG and thus make the ball lope and get down the lane better.

The pin down drilling will take a little of the core out at the top (fingers) and still more out at the top (thumb).  This looks to me like it would "decrease" the RG and thus make the ball get in a roll earlier and react earlier on the lane.

This is how I look at it, right or wrong.

As you move the low RG axis you also move the ending location of the high RG axis. The location of these two items in reference to your style and in reference to your PAP will affect the way a bowling ball core reacts. It will also depend on the balls coverstock and intended design.

From a core stand point alone the smaller the VAL angle the quicker the ball reacts to friction. The larger the angle the slower it will react to friction.

As many have stated when the pin is above the fingers or even parallel with the fingers both the fingers and the thumb are taking a lot of mass from one side of the ball. If the pin is down you are taking mass from the top of the core, but depending on the location you are actually taking mass from either side of the top of the core somewhat evenly.  It will not be as affective of a removal as when the pin is even or above.

This affects the way the ball will flare on the lane and how it transitions from one phase to the next. Skid, hook, then roll. More or less skid, a longer hook phase, or a longer roll phase can all add up to a different reaction that we see or don't see on the lanes. The core with flare and how, and how much affect how the surface touches the lanes. The surface in combination with those aspects can be a big difference (high performance ball) or a very little difference. (lower or no performance ball)

These things are minimal in many cases when thrown on a THS. It can hide these things because of the oil volume and how the pattern literally shapes the ball on the lane.

There are certain beliefs in ball motion that could easily fall into the irrelevant relevant category....static weights, pin up vs pin down, pearl vs solid...in a sense these have been simplified in regards to ball motion.

Static weights is obviously a horse that has been beaten to glue...

Pin up vs pin down should be also looked at in a simplistic manner - if you place a pin directly below or just above the gripping holes is there a true difference? NO - if you place a pin 1" below or 1" above the gripping holes is there a difference...

Due to the densities of the cores and how they are manipulated to create top weight or pin outs are slight core shifts - 1/32" shift from true center if the mass to create a 1" pin out or 1oz of top weight....now take into consideration that each situation will or could result in differing amounts of mass when placing the gripping holes - inserts vs no inserts and actual size & depth of gripping holes. I know when I was still drilling professionally, we drilled the finger holes 2-2 1/8" deep and the thumb holes 2 5/8" deep to somewhat even out Thea's distribution. If we wanted to slightly alter the reaction we'd adjust the depths but how much is where the reaction is altered?
All of these things are a variable but truly at what point does it change? How much is visible over actual? How much is what we think over what is actually happening? I love drilling pins out a lot if times...what would that be? Pin up or pin down?

Trust me these factors are as much perception as it is reality...every situation can be deemed different in regards to the amt of built in friction side to side and front to back...

Make bowling simple...cover strength, surface prep and pin to pap to manage flare then add a weight hole to alter movement...if you like pin ups then by all means use them...much of the game is confidence...if you have confidence in a layout...use it!

Thanks Ric for the simple and realistic view.  I kinda see this much like surface of the ball.  Too many times people get caught up in the exact grit used on a ball.  "I like everything at 2000!!!!"  But in reality, every 2000 is different.  If the ball is not transitioning early enough, go with a lower grit, if it is early, go with a higher grit.  Simple.  It may be good to have a general understanding of where you started and how you got to where you ended up, but don't get caught up in the exact numbers. 

Bowling is an area where I feel you can be reactive and open to change instead of trying to be proactive and guess what is going to work.

Rico,

Would saying that you can discern the static weights in the ball motion be akin to saying..."I can tell the difference in a fresh 2000 pad and one that has 1-2 uses"?

Not sure if this is an accurate comparison....

I have a suburban and I removed the floor mats to go faster and get better gas mileage

preception vs reality