The Bowling Rule of 31

Oil patterns are frequent talking points on bowling blogs and forums. Most bowlers, regardless of skill level, know and understand the distinction between light, moderate, and heavy oil patterns and what bearing this has on their performance—depending on their ball. 

The most common pattern and the default oil application that recreational bowlers tend to encounter is known as the house pattern.

This is where oil is applied more generously down the center of the lane whereas the stretch that lines the gutters is left considerably drier. This gives the ball a little extra push to hook back on course should it deviate from its intended path.

Generally speaking, the house pattern involves the oil being applied up to the first 35 to 45 feet of the bowling lane’s entire 60-foot length

It’s done in such a way to assist beginners and intermediates, as the dry 15-25 foot stretch at the end means the ball will only usually begin to hook immediately before the pins. It also means the ball will be more likely to curve inwards if it gets too close to the gutter.

Length is the operative factor here, as it ultimately dictates where your ball will begin to hook. This will also massively vary depending on what ball you have, its weight, core, and how absorbent the coverstock is. 

What is the bowling rule of 31?

The rule of 31 is a common topic in bowling books and among players. It is a sort of formula that can help you approximate what board your ball will be at by the end of the oil pattern.

For example, if you’re bowling over an oil pattern that spans across 45 feet of a 60-foot lane, you would subtract 31 from 45. This would leave you with the number 14. 

This result is the approximate board that your ball would be at when it exits the oil pattern (board refers to the 31 actual wooden boards that the lane is composed of). In this instance, you’ll want the ball to be at the 14 board when it exits the oil pattern.

Conversely, if you were to be using an oil pattern that spans the length of 35, your ball would land at the 4 board when exiting the oil pattern. This, however, is not the same as the breakpoint which will be a few feet further down.

This figure will help you dictate how to best approach the lane depending on the length of the oil pattern.

Considering the degree of hooking capacity you have depending on the length of the oil pattern, this allows you to adjust your spin accordingly.

What do the pros think?

The term ‘rule’ can be deceptive, however. It should by no means be treated as a mantra that will give you infallible results every time. 

Shannon O’Keefe, coach of Mckendree University and WPBA bowler, echoes this same sentiment when she proposed the term ‘guide of 31’ via Instagram as an amendment so as to put to bed any potential misconceptions. 

Is the rule of 31 reliable?

It’s been argued that the rule of 31 is mainly applicable at tournaments where a lane is allocated to each player during warm-ups, making it easier to anticipate the pattern. 

However, this rule or rough guide is helpful when noting one key element—the shorter the pattern, the wider the curve. If you can ascertain that the ball will depart the oil pattern at, say, the 4 board, then you can anticipate a wider hook than if it were to exit at the 14 board.

The rule of 31 is more traditionally applicable to sports shots rather than when bowling on conventional public lanes. This is because it’s possible to ascertain the ball’s reactivity on freshly oiled lanes. 

Whereas if you’re bowling on a house pattern, you have to factor in the varying lengths that are difficult to account for and the oil getting chopped up and absorbed by other plays.

Difficulties are liable to arise when applying this method to house patterns if you take into consideration the traditional shape of the oil application on public lanes. 

House lanes typically have oil applied in a triangular shape with a limited amount outside the 10 board at 15-20 feet and the 15 board at 30 feet. If you try to apply the rule of 31 when working to this style of application, your ball would generate a substantial amount of friction and hook too early. 

This is on top of the inconsistencies in oil levels as a result of repeated plays. In short, if you’re throwing across a house pattern, coming in as far left or as far right as is comfortable is the safest way to play it.

Advantages

  • An efficient way to determine the hook of your ball
  • Can secure you some serious results on the right oil application
  • Helps you find the best breakpoint
  • A great starting point, even if not wholly accurate

Disadvantages

  • Doesn’t necessarily apply to house patterns
  • Not always reliable, even on consistent oil applications

Overall

The bowling rule of 31 is a helpful guideline if you’re trying to assess how your ball will react to a freshly oiled surface. Much of the time, you’ll be surprised by your performance when working by the rule too, but be mindful not to treat it as gospel—especially on house applications.