Found this article in my archives.
Written by John Williams, BTBA Natoinal Coach
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Is your bowling ball too heavy or too light for you? Do you tire after a while so that your pendulum swing starts to waver? Then, probably, your ball is too heavy. If, on the other hand, you can hardly feel the ball on your hand during the swing, it may be too light.
Young lads in their teens and men mostly suppose that they should be using 16- pound balls (the macho syndrome) and a lot of ladies think 'Light is Bright!'
Today, in bowling, we have sophisticated bowling ball dynamics and materials. So, would it make much difference if you changed to a different weight? It used to be considered that the 16-pound ball would have more carrying power.
The ABC (American Bowling Congress) and the WIBC (Women's International Bowling Congress) have recently looked into the strike ability, corner pin (7- and 10- pins) and splits left resulting from different bowling ball weights.
The results showed that 'heavier is better', but not as true as most bowlers think. For many bowlers who have difficulty in scoring consistently with a 16-pound ball, a lighter ball of one or two pounds could offer advantages that could more than make up for the difference in weight.
The strike power of various weights was tested by using an automated ramp at the Equipment Testing Laboratory in Greendale, Wisconsin. Eight to 16-pound balls were used and all of the same brand, otherwise the testing would not give a true result.
Different angles of entry were used and the experts decided to use three different angles, i.e. two, four and six degrees, which would correspond to moderate or substantial hooking power, giving a complete range of potential 'Strike Shots'.
Technically, the strike pocket is measured by 'offsets', that is the distance between the centre of the ball and the centre of the head pin.
If the centre of the ball was in direct line with the centre of the head pin, then this would be called 'zero offset'.
A 2.5 inch offset is basically the perfect strike hit for all entry angles and all ball weights. If you remember my article of last December about the 'Basic Adjustment' for getting your ball into the pocket, there is 12 inches between the centre of the head pin and the centre of the 3-pin and also between the centre of the head pin and the centre of the 2-pin. There are normally 39 boards in a lane and the width is between 41.5 and 42 inches, so each board is more or less 1.076", so the strike pocket is approximately 17.5 boards in from the right, or the same from the left for left-handers.
During tests, ten shots were rolled at quarter-inch offset increments for 0.5 inches to 5.5 inches and a total of 210 shots were made for each of the three entry angles.
The two degree angle represents those who roll a minimal hook; the four degree shot represents a 'stroker's' moderate hook; and the six degree entry represents a 'cranker's' big hook.
The testers then entered all the findings into 'Strike Probability Charts', detailing the number of strikes recorded for each weight and entry angle, noting the area which resulted in 70% or more strikes.
The charts clearly show that the width of the strike pocket increases with the entry angle. Ball weight is a factor, but not as important as the entry angle.
As examples, a 16-pound ball with a six degree entry angle produced a strike pock- et 3.25 inches wide. Going down in weight to either a 14 or 15-pound ball with other factors the same, the strike pocket becomes a little less to about three inches, but the difference is only a quarter of an inch. Therefore, the 14 and 15-pound balls can give more or less the same percentage of strikes as the 16-pound ball.
"LIFT" AND "ROTATION"
The next item taken into consideration is 'lift' and 'rotation' from each weight of ball. If the same amount of lift is generated to a 14 as to a 16-pound ball, it should provide a greater angle of entry for the lighter ball as it is easier to rotate a 14 than a 16-pound ball. Bearing this in mind, by coming down in weight from 16 to a 15-pound ball can increase the angle of entry and widen the strike pocket by up to 0.75 inches, Which could create an extra 33% additional margin of error.
The next consideration following the findings that the strike parity is pretty close between the 14, 15 and 16-pound balls is the carry, especially leaving the 10-pin for right- handers, the 7-pin for lefties.
The results from the testing showed that there was not much difference between the 14, 15 and 16-pound balls. However, at a two degree angle the 16-pound ball was inclined to leave a 10-pin when the line was 3.5 inches offset, that is approximately one inch wide of the perfect strike target. The 14 and 15-pound balls had a lower percentage of 10-pin leaves, but that was with a wider offset range.
"ANGLE OF ENTRY"
At a four degree angle of entry, the 16- pound ball had a wider offset area of 3.5 to 4 inches before the 10-pin was inclined to be left, but the offset area for the 14 and 15- pound balls was less.
At a six degree angle of entry, all three weights produced a higher percentage of random 10-pin leaves. However, the 16- pound ball left far fewer 10-pins than either of the 14 or 15-pound balls when it was a light pocket hit.
Overall, the number of 10-pin leaves for right-handers and 7-pin leaves for left-han- ders over all three angles of entry was pret- ty much the same. It was also found that the 16-pound ball has a slightly better car- rying advantage.
The next item of interest to the testers was the predictability of leaving splits according to ball weight. It was difficult to come to any overall conclusion because of the various factors that can enter into bowling during league or tournament play.
The ramp test did show, however, that a bowler is at a definite disadvantage when using an 8-pound ball. The 10 and 12- pound balls caused a lower percentage of splits, whilst the 14, 15 and 16-pound balls were fairly even and less still.
The tests also showed that a six degree angle of entry left fewer splits, regardless of ball weight.
Finally, it shows that a big hook will help to reduce the number of splits which may be left.
Extract taken from World Of Tenpin July 1995
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Duke Harding
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