Dual Angle Ratio Guide

TOTAL SUMS

Degrees of drill angle + degrees of val angle = TOTAL SUMS

Note: The total sums of your sweet spot will include a (+or- degrees).

Adding these degrees to your total sums will add length to ball motion ' (increasing total length of ball motion before reaching the roll phase.

Subtracting these degrees from your total sums will decrease the length of ball motion.

EXAMPLE: Sweet spot of 100* (+or-20*)

For dry or short oil patterns to increase length use 120* sums. (use a large ratio for a long & strong layout or use a small ratio for a long & smooth control layout)

For oily or longer patterns to decrease length use 80* sums. Utilizing ratios to achieve the desired break shape (high ratio = defined /sharp motion...low ratio = mid-lane roll.)

RATIO DISCUSSION

RATIOS DETERMINE THE BALLS BREAK SHAPE

The drill angle helps determine the length of the skid phase of the ball motion.

The val angle helps determine the length of the hook phase of the ball motion.

The drill angle + val angle = the total length before the ball reaches the roll phase of the ball motion.

Higher ratio of the drill angle to the val angle = longer & quicker reaction to dry. (more of a skid /snap ball motion. The lower the ratio the smoother the break shape).

finding your BENCHMARK RATIO

This is necessary To accurately calculate the drilling angle and the val angle individually.

(step #1) Find initial tilt ratio on Athery's tilt chart

(step #2) Adjust this ratio higher or lower for high or low rotation. ( move box to left or right on chart. note: extreme speed or rev dominance can accentuate this which requires more of an adjustment)

(step #3) Calculate the ratio range. (this is necessary to calculate all layouts to personalize your desired ball motions.)

(step #1) find INITIAL RATIO from TILT

. The middle column (Initial Ratio Benchmark range) gives approximate ratios for bowlers with speed/revs = matched + normal rotation.

Please note: When doing the chart we used 50*-55* as normal rotation. (45* as slightly low and 60* as slightly high.)

For TILTS BELOW 7* (especially when accompanied by high rotation) use PDF chart at bottom of page,

For TILTS BELOW 7* accompanied by low rotation use Athery"s chart.

CHART IS BY ATHERY

(step #2) adjust for HIGH OR LOW ROTATION

high rotation and/or high rotation with extreme speed dominance=DECREASE RATIOS.
(adjust to boxes further right on the chart)

low rotation and/or low rotation with extreme rev dominance = INCREASE RATIOS.
(adjust to boxes further left on the chart)'

(step #3) find your RATIO RANGE

The maximum ratio and minimum ratio (drill angle/val angle) which should be utilized with your personal sweet sums is termed your RATIO RANGE.This is how far you can deviate your ratio both higher and lower from your benchmark ratio. It can be calculated by choosing boxes left and right of your chosen ratio on the chart above. Mo very seldom gives an extremely large ratio range. It is more common with very low or very high tilt. A +or- of around .5 above or below benchmark ratio seems to be close to average ratio range.

You need to determine your personal ratio range to utilize in conjunction with your total sums to accurately calculate your preferred layouts or sweet sums.

Mo frequently uses the lower ratio range for control drillings for easy conditions or wet/dry. He frequently uses the higher ratio range for more challenging conditions.

PLEASE NOTE: On ratios less than 1:1, Mo sometimes expresses ratios with the val angle reduced to :1

1:1.25 would be expressed as .8:1 (.8:1=1:1.25, etc.)

for TILTS BELOW 10*

With low tilt, the rotation seems to effect the ratios a lot more than with medium tilts. A high rotation will decrease them a lot (what Mo calls PDW territory) and a low rotation will significantly raise them. There is more of an extreme adjustment comparitively. The ratios increase as the tilt decreases until you reach below 7*-10*. below that the ratios decrease. Part of the reason is because the maximum drilling angle is 90* and with low tilt, you need ratios which will take the ball down the lane. Here is a PDF chart on how to adjust Athery's chart when low tilt is accompanied by high rotation.

CLICK ON "LOW TILT CHART" below

Low tilt chart