Dual Angle Ratio Guide
Contributed by Elgavachon and Athery
Recommended Readings Before Beginning
You absolutely need to have studied Mo's Dual Angle Layout Technique article in the wiki before continuing here. You should also have studied Matt's How To Apply Dual Angle/Sweet Spot article in the wiki. (to calculate total sums)
Total sums determines the length of ball motion until the roll phase (See: Three Phases of Ball Motion)
- Degree of drill angle + degree 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 the 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.
Sweet spot of 100º (± 20º)
For dry or short oil patterns to increase' length, use 120º sums.
- Use a high ratio for long and strong layouts.
- Use a low ratio for control layouts.
For oily or longer patterns to decrease length, use 80º sums. (utilizing ratios to achieve the desired break shape)
- Use a high ratio for defined/sharp motion.
- Use a low ratio for mid-lane roll.
Ratios determine the balls break shape.
- The drill angle helps determine the length of the skid phase of ball motion.
- The val angle helps determine the length of the hook phase of ball motion.
- The drill angle + val angle = the total length of ball motion before the ball reaches the roll phase.
- A higher ratio of the drill angle to the val angle = longer and quicker reaction to the dry. (more of a skid /snap ball motion)
- A lower ratio of the drill angle to the val angle = earlier and slower reaction to the dry (smoother & more continuous ball motion.)
Finding Your Benchmark Ratio
This is necessary to accurately calculate the drilling angle and the val angle individually.
- Find initial tilt ratio (see table below).
- Adjust this ratio higher or lower according to your axis rotation.
- Move box to left or right on chart. Extreme speed or rev dominance can accentuate this which requires more of an adjustment.
- If there is no (primary ) adjustment necessary for high or low rotation, you do not need to adjust for speed or rev dominance (secondary)
- Calculate the ratio range.
- This is necessary to mathematically calculate your personal desired ball motions/layouts. (control, long and hard, mid-lane, strong oil, etc.)
- For examples on how to do the math, see simple math examples.
Step #1 - Find The Initial Ratio From Axis Tilt
The middle column (initial ratio benchmark range) gives approximate ratios for bowlers with speed/revs = matched + normal rotation.
Please note: when creating the chart we used 50º to 55º as normal axis rotation. (45º is slightly low and 60º is slightly high)
- For axis tilt below 7º (especially when accompanied by high rotation) use this PDF chart.
- For axis tilt below 7º accompanied by low rotation use the chart below:
- For low axis tilt with very low revs use the chart below (even with high rotation):
Special notes for axis tilt below 7º: 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 7º to 10º; below that the ratios decrease. Part of the reason is because the maximum drilling angle is 90º 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, especially when low tilt is accompanied by high rotation.
Step #2 - Adjust For High Or Low Rotation
Amount of adjustment necessary depends on the relationship between rotation and ball speed.
- High rotation and/or high rotation accentuated with speed dominance = decreased ratios (use boxes further right on the chart)
- Low rotation and/or low rotation accentuated with rev dominance = increased ratios (use boxes further left on the chart)
Step #3 - Find The Ratio Range
The maximum ratio and minimum ratio (drill angle and val angle) which should be utilized with your personal sweet sums is defined as 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 +/- of around 0.5 above and 0.5 below benchmark ratio seems to be close to the average ratio range.
You need to determine your personal ratio range to use in conjunction with your total sums to accurately calculate layouts for your personal specs or sweet spot.
- Mo frequently uses the lower ratio range for control layouts, and easier lane conditions.
- Mo frequently uses the higher ratio range (a defined break shape) on more challenging lane conditions.
Please note: On ratios less than 1:1, Mo sometimes expresses ratios with the val angle reduced to :1 example: 1:1.25 would be expressed as .8:1 (.8:1=1:1.25, etc.)
Drilling and Val Angle Examples
The following are examples of how to do the math for the ratios. You will divide the total sums of the layout by the sum of the ratio you are looking for. Remember with this simple math, you are always finding the smaller angle (drill angle or VAL angle) of the ratio.
Smaller VAL Angle Example
- 90º total sums with a ratio of 2:1
- 90º divided by 3 = 30º val angle
- 90º - 30º with a 2:1 ratio = 60º drilling angle
- Results in a 60º drilling angle and 30º val angle.
Smaller Drill Angle Example
- 90º total sums with a ratio of 1:2
- 90º divided by 3 = 30º drilling angle
- 90º - 30º with a 1:2 ratio = 60º val angle'
- Results in a 30º drilling angle and 60º val angle.
Control Layout Example
Find a control layout from 90º total sums using a 2:1 ratio (+/- 0.5). For a control layout, you would add the 20º and subtract the 0.5 ratio.
- 90º + 20º = 110º total sums
- 110º divided by 1.5:1 ratio (ratio has been adjusted with -0.5)
- (1.5+1)= 2.5
- 110º divided by 2.5 = 44º (round to 45º val angle)
- 110º - 45º = 65º drilling angle
- 65º drill angle with 45º val angle = a control layout using 90* (+/- 20º) total sums with a 2:1 (+/- 0.5) ratio.
Long & Strong Layout Example
Find a long and strong layout from 90º total sums using a 2:1 ratio (+/- 0.5.). For a long and strong layout, you would add the 20º and add the 0.5 ratio.
- A control layout using 90º (+/- 20º) with a ratio of 2:1 (+/- 0.5)
- 90º + 20º = 110º total sums
- 110º divided by 2.5:1 ratio (ratio has been adjusted with +0.5)
- (2.5+1) = 3.5
- 110º divided by 3.5 = 31º (round to 30º val angle)
- 110* - 30º = 80º drilling angle
- 80º drill angle with 30º = a long & strong layout using a 90º sums (+/- 20º) with a 2:1 (+/- 0.5)ratio.
Mid-lane Layout Example
Find a mid-lane layout from 90º total sums using a 2:1 ratio (+/- 0.5). For a mid-lane layout, you would subtract the 20º and subtract the 0.5 ratio.
- 90º - 20º = 70º total sums
- 70 divided by 1.5:1 ratio (2:1 ratio adjusted with the -0.5)
- 70º divided by 2.5 = 28º (rounded to 30º val angle)
- 70º - 30º = 40º drilling angle
- 40º drill angle and 30º val angle = a mid-lane layout using 90º (+/- 20º) with a ratio of 2:1 (+/- 0.5)
Totally Strong Layout Example
Find a totally strong layout from 90º total sums using a 2:1 ratio (+/- 0.5). For a totally strong layout, you would subtract the 20º and add the 0.5 ratio.
- 90º - 20º = 70º total sums
- 70º divided by 2.5:1 ratio (ratio has been adjusted with +0.5)
- (2.5+1) = 3.5
- 70º divided by 3.5 = 20º
- 70º -20º = 50º drilling angle
- 50º drill angle with a 20* val angle = a totally strong layout using 90º (+/- 20º) with a 2:1 (+/- 0.5) ratio.