What is the rule of 31 and how can you use it to help your bowling? If you are here now you are looking for information on the rule of 31 in bowling.
I think this is some good information to know especially if you are bowling in a tournament in a house you never bowled in before. And it could also help if you are contemplating joining a sport shot league.
The pattern of oil that will be used in any tournament is readily available. And Sport Shot leagues will give you the information on every oil pattern they will be using during the season. Once you get the specs on the pattern length and volume of oil, you have the information you need to get an approximate line to the pocket established.
The Bowling Rule Of 31 – Oil Patterns
Before we get into the Rule of 31, I wanted to explain the difference in oil patterns.
Not everyone knows that there is a lot of difference between the normal House Shot and other oil patterns. The league oil can be a fresh house shot or slightly longer and more difficult. Tournaments and Sport Shots are even more challenging. So, let’s explore different oil patterns.
The House Shot
The house shot is an oil pattern designed to be friendly to the bowlers. It actually helps them make better shots. The outside of the lane is dry to help a ball missing outside to hook back to the pocket. And the oil is heavier in the middle to help the ball slide more if you miss inside.
It is a more forgiving pattern to help make your game more enjoyable and let you achieve higher scores. This is what the bowling alley wants. They want you to come back. If the oil pattern is too difficult you probably won’t come back. So, a good house shot is just good for business.
But, more experienced bowlers want to challenge themselves with more difficult patterns like sport shots. These are the patterns that are used by the Professional Bowlers Association (PBA). Some bowlers just want to see how well they do on the same oil patterns as the Professional Bowlers .
The Sport Shot
The sport shot is basically the PBA patterns. Some are considered easier and some are very challenging. The patterns that are considered a short oil pattern are 35 feet of oil or less. While some are medium oil patterns between 35 -and 40 feet. And oil patterns considered long patterns are over 40 feet.
To determine where you want to start lining up your strike line, a quick tool is very helpful. That is where the rule of 31 come into play. Because on the different oil patterns, standing in the same spot, trying the same line won’t work.
Tournament Oil Patterns
Tournaments hosted by the PBA and USBC sanctioned tournaments will display what pattern is being used on the lanes. They will tell you the oil length and the type of pattern being used.
And they also tell you the volume of oil that is put on the lanes. This information gives you the ability to determine a good area for targeting the strike zone.
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You can do this by using the rule of 31. You subtract 31 from the length of the oil pattern. That determines the (approximate) board number where your ball will exit the oil.
Once you know that, you can expect your ball to stop sliding a few feet later, and begin to hook. That is the breakpoint of your ball. Here is a short video to help clear this up.
The Bowling Rule Of 31 – Where Is The Breakpoint
Is The bowling Rule Of 31 Perfect? No, But it helps
The bowling rule of 31, is giving you an approximate board where you ball is exiting the oil. Then it will begin to hook and finally end up in a roll to the pocket. Hopefully the result is a strike!
But, there are many variables that can affects your ball skid/hook and where it eventually hits the pocket. There are 3 phases that your bowling ball uses to get strikes.
The Three Phases Of Ball Motion
- Skid – where the ball is the fastest, it slides through the oil
- Hook -when the ball exits the oil pattern and starts to hook (Breakpoint)
- Roll – the slowest phase, the ball stops hooking and rolls into the pocket.
When your ball is in the oil pattern it is skidding until it exits the oil. Then, it hits the dry portion of the lane. This is the area, where you ball begins to hook. The friction on the lane causes the ball to react and hook.
Again, this is your breakpoint. The breakpoint is affected by the speed of the ball, and the amount of revs on the ball. Plus the length of the oil pattern and the volume or thickness of the oil. Even the humidity in the air can affect how fast or slow an oil pattern can be.
That is why, the rule of 31 can vary on many other factors. But, the beauty of the rule of 31, gives you a starting point. Then, with a few slight adjustments, you can line up an effective area to get more strikes! Isn’t that what we want? It’s sorta like the secret nobody ever told you about!
How Do You Use The Bowling Rule Of 31?
Now you have some basics of the factors that contribute to bowling strikes consistently. How do you use the rule of 31 to your advantage? It pretty simple really.
If the house shot is 40 feet long, minus 31, your ball will exit the oil on the 9 board. So you want to target your ball to roll over the 9 board. Then, your ball should reach it’s breakpoint within a few feet of exiting the oil.
At that point, the ball is on the dry portion of the lanes. You can expect the ball will begin to hook toward the pocket.
Watch the motion of of the ball as it begins to hook. It also should start into a roll before it strikes the pins. This is the ball delivering all the energy it has to the pins.
If you are on the best line, with the right speed, you should be close to the strike sweet spot. And the result is hopefully a strike. Do you see how helpful this can be?
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Bowling Rule Of 31 – Determining Oil Pattern Length
How do you determine where the oil pattern ends? One way is to watch your ball as it goes down the lane. When it begins to hook, that is the point it is encountering the dry portion of the lane.
And as the game progresses more oil will be carried down onto the dry portion, changing the reaction of your ball.
Rangefinders also called Downlane Markers help you determine where the length of the oil pattern ends. The rangefinders are the 4 colored boards that appear on the lanes.
They are found about halfway to three quarters of the way down the lane. Not all alleys have them, but they are very helpful if your alley does have them.
The first two boards closest to the bowler are on the 15th and 20th boards. They are 3 feet long and stretch from 34 to 37 feet downlane. The second set are farther apart and located across from each other at the 10th and 20th boards.
They are also 3 feet long and stretch from 40 to 43 feet. So, knowing those numbers you can now determine where the different oil patterns actually end on the lane.
Longer Oil Patterns
If you know you are bowling on longer oil pattern, the your ball will hook less. So you will want to move inside a bit to account for the diminished hook. Let’s see how the rule 31 works on longer oil.
Let’s say you are bowling on the PBA Badger oil pattern. It is the longest PBA oil pattern at 52 feet! So let’s apply the rule of 31. Take 52 -31 = 21. The 21 board is 12 boards left (for right handers) of the 9 board used on the house shot.
This is playing a much straighter line. Now, your ball is going to skid 12 feet longer before it hits the dry surface on the alley. It also means you have very little area left to get you ball to hook!
The Correct Angle Makes All The Difference
So, you are going to have to adjust to the right to open up the angle to the pocket. Why? Because using 12 board puts your breakpoint basically right in front of the pins. The shot is too straight for good pin carry. You will get some strikes, but every shot needs to be perfect.
Playing your target board that straight to the pocket is hard. A slightly errant shot to the right, leaves a washout, or a left side picket fence(1-2-4-7). If you miss left, you will also get a right side washout or a bad split.
Give yourself enough room, take the ball out a bit to the 15-18 board. This will help to open that angle to the pins. You need angle to increase your pin carry. Using that angle increases your chances of getting strikes and making it easier!
This is an example of why the bowling rule of 31 is not perfect. You have to be open to making slight adjustments! Once you realize that, you are on your way to a more enjoyable bowling experience!
Shorter Oil Patterns
On shorter oil patterns the rule of 31 will need some adjustment as well. The shortest PBA pattern is the PBA Wolf animal oil pattern. It is only 32 feet long, so subtracting 31 =1. If you were bowling on this pattern, you would try to target the 1 board (using the rule of 31).
It is easier to target a bit inside (2-3board) to keep the ball from ending up in the ditch!
I personally am not comfortable with a shot that close to the gutter, and would try to target the 4 board and move my feet left as much as I need.
This is another example why the rule of 31 is not considered to be the end-all for targeting oil patterns. But, what it does give you, are some pretty accurate locations to expect your ball to start breaking. The most accurate results are in the mid-range oil patterns of about 35 to 42 feet of oil.
Patrick Hanahan PBA Tournament Bowling
Watch PBA bowler Packy Hanarahan when he bowled in the David Smalls Best of the Best PBA Tournament held 2/09/2022. The oil pattern used was the PBA Viper Pattern.
This pattern is 36 feet Long. The structure is very light or no oil on the 1-2 boards. Then a heavy oil shelf at around 12 board. It is what Packy labels The Easiest PBA Pattern Ever. And it makes sense.
It is like the ultimate house shot pattern for shots missed inside as well as outside. But, the volume is light, so you may need to adjust with a ball change late in the match.
Packy had success using the Purple Hammer urethane ball. This is what bowling on the pattern looked like for other PBA bowlers as well.
The Bowling Rule Of 31 Helps Everyone
As you can see even the PBA bowlers use the same rule to establish where they want to play each pattern. To them, it is almost automatic when they see the length of oil and the volume. It is a no brainer whether they will be playing the outside or inside on the lane.
They used the rule of 31 to get established, then the practiced adjustments and ball changes. It is a fact, we can do the same things and make our games easier and more enjoyable.
I hope you have learned something, and I have helped you improve your game. I welcome any experiences you want to share. Thank you for reading.
If you have any questions or comments, please leave them below.
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