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Fit Question

Posted: January 10th, 2018, 11:42 am
by deanchamp
Hi all, I have just rechecked my grip as it had been nearly 3 years, and when going through the process a question arises that I don't recall seeing the answer to.

Using the Morich fitting system, my recommended fit is:

Thumb Pitch
7/16” Reverse (90 degree ave tight + 1/8" reverse for long thumb)
1/8” Left

Middle Finger
Middle Finger Span – 4 5/8”
Linear – 1/8” Reverse
Lateral – 3/8” Left

Ring Finger
Ring Finger Span – 4 3/8"
Linear – 1/8” Reverse
Lateral – 1/2” Right

Which is similar to what I've been using, except I've had 1/4" fwd in my thumb for years, so I reduce the span to compensate.

BUT as the linear finger pitch is determined from the thumb pitch, should I base my finger pitches off the thumb pitch I actually use, or the thumb I am recommend to use?

I'm assuming it's the former, but any clarification is appreciated.

Dean

Re: Fit Question

Posted: January 10th, 2018, 4:32 pm
by Arkansas
The original span-to-thumb pitch chart is in Bill Taylor's book on fitting. In it he states that the span to pitch relationship is used to maintain a 63* angle, which he says is the optimal release angle. For this reason I would think that you'd need to base it off the thumb pitch you actually use. He goes on to say that if a bowler has a good fit and wants to experiment with an additional 3/8" forward in the fingers they should reduce the span 1/16". So it's based on the actual pitches used.

Re: Fit Question

Posted: January 10th, 2018, 6:39 pm
by stevespo
Arkansas wrote:The original span-to-thumb pitch chart is in Bill Taylor's book on fitting. In it he states that the span to pitch relationship is used to maintain a 63* angle, which he says is the optimal release angle...
I'm curious - could you elaborate on what the 63* angle is?
Thumb angle along the grip centerline plane?

I've been trying to locate that book for years. They show up for big $$$ from time to time.

Thanks,

Steve

Re: Fit Question

Posted: January 10th, 2018, 7:59 pm
by elgavachon
I heard somewhere (don't remember when or where) that the new information is using 1/4" more forward in the thumb than the old charts. Any one hear this who can clarify? New IBSIA classes maybe?

Re: Fit Question

Posted: January 10th, 2018, 9:20 pm
by Arkansas
See attached from the book.

Re: Fit Question

Posted: January 10th, 2018, 10:15 pm
by bowl1820
Thought I'd throw this in for you:

Troubleshooting Grips Issues: The Coaches and Pro Shop Operators Guide to Grip Symptoms and Fixes

The 63° is mentioned on page 3.
Troubleshoooting-Grip.pdf

Re: Fit Question

Posted: January 11th, 2018, 1:57 am
by guruU2
Arkansas wrote:See attached from the book.
Arkansas wrote:Attachments
The 63o is extremely important. Bill Taylor, back in the 50's and 60's, did the "grunt" work for up by plugging and drilling over and over and over and over came to the conclusion that the hand, for most bowlers (er 90% plus) should sit in the ball at 63o. A couple of computer studies in the early 90's (sorry, I forgot them as named references) came to the conclusion the hand should sit in the ball at 61.7o thus confirming Bill's work (who did this "grunt" work with out computer help). There are exceptions to this (Del Warren, for example, is one due to his physical uniqueness to his hand). The IBPSIA chart is rock solid guideline for thumb pitches for most people most of the time.

Re: Fit Question

Posted: January 11th, 2018, 11:59 am
by ads
bowl1820 wrote:Thought I'd throw this in for you:

Troubleshooting Grips Issues: The Coaches and Pro Shop Operators Guide to Grip Symptoms and Fixes

The 63° is mentioned on page 3.
Troubleshoooting-Grip.pdf

How does it define length of span, edge to edge (with finger inserts and ST) or cut to cut (without finger insert and ST)?

Re: Fit Question

Posted: January 11th, 2018, 1:15 pm
by bowl1820
ads wrote:

How does it define length of span, edge to edge (with finger inserts and ST) or cut to cut (without finger insert and ST)?
A persons span is measured from gripping edge to gripping edge.

Re: Fit Question

Posted: January 11th, 2018, 6:19 pm
by TonyPR
The Wiki fit is just a starting fitting guide, if you are curious about it follow it exactly as it recommends. In your case I would just adjust from what you have comfortably used for years depending on where it hurts(if it hurts) or what feel changes you wish to achieve. Why do you want to change your fit? Are you having any issues with pain or blisters? If so for how much time have you had them? What are your expectations from the new fit?

Re: Fit Question

Posted: January 13th, 2018, 1:56 am
by deanchamp
Arkansas wrote:The original span-to-thumb pitch chart is in Bill Taylor's book on fitting. In it he states that the span to pitch relationship is used to maintain a 63* angle, which he says is the optimal release angle. For this reason I would think that you'd need to base it off the thumb pitch you actually use. He goes on to say that if a bowler has a good fit and wants to experiment with an additional 3/8" forward in the fingers they should reduce the span 1/16". So it's based on the actual pitches used.
Yeah that's what I was thinking, that the relationship between span and angles has to stay the same.

The 63* angle is interesting, I wonder if that would still be the case with the modern release requiring the fingers stay in the ball a bit longer once the thumb has exited, or if this angle is independent of how you release the ball.

Re: Fit Question

Posted: January 13th, 2018, 2:44 am
by guruU2
deanchamp wrote: The 63* angle is interesting, I wonder if that would still be the case with the modern release requiring the fingers stay in the ball a bit longer once the thumb has exited, or if this angle is independent of how you release the ball.

A most interesting insight. I knew Bill for his last 10 years and my sense is that he would hold that the "angle is independent of how you release the ball". Yet, he did recognize that the 63o was not an absolute for all bowlers all the time.

Re: Fit Question

Posted: January 15th, 2018, 1:32 am
by deanchamp
Thinking about this more, another quirk in the numbers seems to arise when shortnening the span to allow for more fwd in the thumb.

For e.g. If my Middle Finger span was 4 1/2" and I had a 90* thumb angle, I woud get 1/4 reverse in my thumb linear pitch. If I adjusted that to 1/4 forward, my span would be reduced to 4 3/8".

But to get a 1/4 forward on the chart with the same thumb angle, my span would have to naturally be 3 1/2".

So in this respect, I would still be quite overspanned compared to how long my fingers should be for the equivalent foward thumb angle, according to the chart.


Also found this post from Jim M:

Verbatim from the IBPSIA Fitting Manual:
"It is essential to adjust the span when changing forward or reverse pitch".

1) For the fingers, the span adjustment is 1/16” for each 3/8” pitch change.
2) For the thumb, the span adjustment is 1/16” for each 1/4” pitch change.
3) All adjustments should be made off of a good base grip.

Which is slightly different to Bill Taylor's adjustments - he goes on to say that if a bowler has a good fit and wants to experiment with an additional 3/8" forward in the fingers they should reduce the span 1/16".