Abralon Pads - Same effects as Scotch Brites. Pads are made in 180, 360, 500, 1000, 2000, 3000, and 4000 grits. 

  • 180 will produce the earliest hook of all pads.
  • 4000 will produce the most length of all pads.


A tried and true coverstock material introduced in the late 1990s that set the standard for modern shell technology.


The area immediately in front of the lane before the foul line measuring at least 15 feet in length and not less than the width of the lane.

Approved- Used to describe equipment that has been sent in, reviewed, tested and found to meet all current specifications at the time of approval.

Asymmetrical Core

A ball where the RG (radius of gyration) values of the Y (high RG) and Z (intermediate RG) axes of the ball differ by more than 5% of the total differentialof the ball.

Axis Migration

Path of which the axis point travels across the surface of a ball as the ball travels down the lane; this path will always have the approximate same RG measurement as the ball travels.

Axis Point

One of two points located on opposite poles marking the end points of the axis of rotation.

Axis Rotation

The measurement of horizontal angle through which a ball rotates; rotation is synonymous with the amount of "side roll" a bowler has.

Axis Tilt

The measurement of the vertical angle through which a ball rotates; tilt is synonymous with the amount of "spin" a bowler has.


Back End

The angle or degree of hook at the breakpoint. Back End is not where the ball hooks, but how much it hooks when it hooks.

Back Ends

Portion of the lane after the lane conditioner ends up until the pins.

Balance Hole

An extra hole, drilled in a specific position, that is used to either fine tune a ball's reaction or bring it within legal game play specifications.

Ball Track

The portion of the bowling ball, which comes in contact with the lane as it rolls down the lane.

Break Point

Occurring during the hook phase, the break point is the position on the lane where the ball is the closest to the outside, or the apex of the curve. Note that arcing balls have a longer hook phase than the comparatively short hook phase of a 'Skid/Snap' reaction.




Refers to the oil that travels to the previously-dry backends. This condition results in less overall hook.

Center of Gravity

The imaginary point inside a body of matter where the total weight of the body is thought to be concentrated.

Coefficient of friction, COF

The ratio of the force opposing the relative motion of two surfaces and the normal force acting perpendicular opposing force. In bowling, this term usually defines the interaction between the coverstock, lane conditioner, and lane.

Coefficient of restitution, COR

The ratio of the energy of two objects after impact to the energy before impact. In the case of a ball striking a pin, this is the percentage of energy transfer from the ball to the pin.


Use to smooth the surface up to 1,500 grit. This will make the surface shinier, decreasing friction levels through the heads, resulting in a later and sharper transition at the breakpoint. 

Conventional Grip

The method of drilling in which the fingers are inserted to the second knuckle and the thumb is fully inserted.


The interior section of the bowling ball consisting of a light-weight filler material, often surrounding the dense weight block shape.

Core Torque

The mass distribution within the arms created by the core (or weight block). Core torque is an assigned value of the balls ability to combat rollout, the complete loss of axis tilt. High torque (High RG) balls are more effective than lower torque (Low RG) balls at delaying rollout. High torque balls will also tend to react more violently on the backend than lower torque balls, which roll more even, displaying a more predictable transition from skid to roll.


The outer shell of bowling balls, which can be constructed with a variety of materials such as Polyester, Rubber, Urethane and Reactive Urethane.


High rev. rate/High axis rotation a player that prefers to play the swing shot, throwing the ball towards the gutter, looking for a big, late backend reaction.



Refers to an instrument (Durometer) used to measure the hardness of the coverstock of a bowling ball.


The difference of the radius of gyration of a bowling balls X axis (the weight block vertical) compared to the radius of gyration of the same balls Y or Z axis (the weight block horizontal). Differential is an indicator of a bowling balls track flare potential. Bowling balls with lower differentials are more stable, therefore generating less track flare potential. Bowling balls with higher differentials are unstable, therefore generating a much larger track flare potential. Also, differential is a guide to the internal versatility of a ball. It can indicate just how much of a length adjustment can be made through drilling. Balls with lower differential will allow only modest length adjustments whereas balls with higher differential may translate into a length window of up to 5-times that of low differential balls.


The surface of a bowling ball, typically without polish, that has a greater amount of friction when in contact with the lane. This is typically a result of sanding a ball with a low grit abrasive surface. (Synonym - Sanded).


Entry angle

This is the angle at which the bowling ball enters the pins relative to the longitude of the lane.


The high RG plane of a bowling ball in symmetrical balls.


Enhanced Traction Mica


Fingertip Grip

Method of drilling where the thumb is fully inserted to the base while the fingers are inserted only to the first knuckle.


The migration of the ball track from the bowler's initial axis (the axis upon release/PAP) to the final axis (the axis at the moment of impact with the pins).Flare is a length modifier. Flare is used to expose fresh, dry ball surface to the lane surface, the entire length of the lane. The greater the Flare, the greater the amount of friction between the ball and the lane; the greater the friction, the greater the hook potential of a ball.

Flare Potential

The maximum amount that the axis of a bowling ball can migrate given the construction of the ball provided that the bowler has a maximum power release. Flare potential can also be used to indicate which balls will be better suited for oily conditions (high flare balls) and which balls will be better suited for dryer lane conditions (low flare balls).


A physics term, when used in bowling, that describes the amount of resistance a ball sustains when in contact with the lane surface. Friction, in bowling terms, is the key factor in converting translational energy (forward speed) into rotation energy (hook).



Pertaining to the texture of the surface of the ball, whether polished or sanded.



The portion of the lane, which extends from the foul line, past the arrows, and to the pine. Usually, this is assumed to be the first 20 feet of the lane.

Hook Phase

Described as a curve, this is the second of three phases of ball motion where the ball has encountered enough friction to change direction. It is in this phase where the break point occurs.

Hook Potential

Refers to the number of boards one ball will cover relative to another.


Intermediate Differential

The difference in radius of gyration between the Y (high RG) and Z (intermediate RG) axes on the bowling ball.


Lane Conditioner, 

Lane Oil

Substance that was developed to reduce friction between the ball and the lane, with the ultimate goal of protecting the lane surface. The greater the volume and length of the oil, the longer the skid phase of the ball before it can transition into its final hook/roll phase. Oil placement can greatly affect scores.

Launch Angle

The angle in which the ball exits your hand at the point of release.


An evaluation of how far a ball will travel before it begins to hook. Length does not include skid caused by lane conditioner, additional fine sanding, or the use of polishes.

Leverage Point

The position located 3-3/8 from the bowlers positive axis point (PAP). Positioning the Pin of a bowling ball on this point, relative to the PAP, creates the most track flare and over all hook of a bowling ball.

Also known as PSA (see definitions), this is typically the highest RG location of the ball, and its position relative to the bowlers initial PAP has a great effect on the subsequent ball motion.



Area past the heads to the end of applied lane conditioner.


A horizontal line half way between the fingers and thumb.


A line perpendicular to the midline that extends through the positive and negative axis points. This line divides the top and bottom halves of the ball on the bowlers axis of rotation.

Moment of Inertia

Resistance to change in rotation.



Oil Patterns

The way oil is distributed onto the lane. Here are the most common used in bowling centers. Top Hat Heavy oil in the middle and very light on the outside. Christmas Tree More oil in the middle than the outside. Tapered to the outside throughout the entire pattern. Sport Permits ratio of 2:1 oil from inside to outside portion of the lane. Used on PBA and PWBA tours. Flat Same amount of oil applied across the entire lane. Reverse Block More oil applied to the outside boards than in the inside.



Perpendicular Axis Line

Also Known As: Vertical Axis Line (VAL)

PAP (Positive Axis Point)

The point upon which the ball rotates off of a bowler's hand, closest to the bowler. PAP values are typically identified by a coordinate system by measuring 'X' number of inches over and 'Y' number of inches either down or up.



A small factory plug that signifies the center of the weight block in most bowling balls.

Pin Buffer

The distance the pin is from the bowlers Perpendicular Axis Line or PAL (also called Vertical Axis Line - VAL).

Pin Deck

The area of the lane on which the pins are spotted.

Pin In

Refers to the weight block being centered in the ball. When this occurs, the pin is within 1 from the cg.

Pin Out

Refers to the weight block not being centered in the ball. When this occurs, the pin will be more than 1 from the cg.


Generally referred to as the middle 20 feet of the lanes. Actually, on wood lanes, it represents the 45 feet between the arrows and the head pin.


Angle at which holes in the bowling ball are drilled.


A coverstock comprised of plastic material. Generally displays a mild ball reaction, and limited durability.


Also popular on the PBA Tour, a Pro-Pin is where the Pin distance from the CG is 5 6 out. Anything more than 6 would be termed an X-Blem. This is a first quality ball and lends itself to several special drill options.


Radius of gyration, RG

An account of the location of the mass inside a bowling ball. Rg tells us whether the ball has the mass toward the center of the ball (low rg), toward the cover of the ball (high rg) or somewhere in between (medium rg). 

  • Low rg balls rev up quickly.
  • Medium rg balls rev up slightly later.
  • High rg balls lope down the lane saving the energy until later.


Polyester chips or flakes, that are added to the shell material for both performance and appearance characteristics. The Reacta-Fleck is large flakes that are added to the coverstock material and protrude from the surface of the ball. This provides for more friction between the ball and the lane than conventional reactive coverstock material.

Reactive Urethane

A coverstock comprised of similar materials used in urethane formulations, however blended with different additives. This coverstock adheres to lanesurface, creating the most backend reaction, the least deflection and the most hitting power of any coverstock manufactured today.


The number of times in which the weight block makes one full rotation around the axis line, as it rolls from the foul line to the head pin.

Rev Rate - A player's Rev Rate will relate to selection of differential, or Flare Potential, for that Particular Condition! 

*To Calculate a Player's Total Revolutions:

Place a stripe of tape from the player's axis point to their ring finger.
Count the revolutions between the player's release and the arrows.
Multiply this number by four (4).

Slower Rev Rate = Stroker - up to 11 revolutions
Medium Rev Rate = Tweener - from 11 to 17 revolutions
Faster Rev Rate = Cranker - greater than 17 revolutions

Roll Phase

The third and final phase of ball motion where the ball is traveling on a linear path towards the pins.



This is an abrasive that is used to scuff or sand the ball surface to create different ball reactions or used to resurface the ball cover after the wear and tear from use. We recommend these 3 types of grits. 1. Burgundy this is the roughest and equates to 240-grit sandpaper. 2. Green this is the medium textured pad and it will produce a 500-600 grit finish. 3. Grey this is the smoothest and finest grit pad. Will adjust the surface to an 800 finish.

Serial number

An identifying series of numbers and/or letters in order to identify a specific ball.

Skid Phase

The first of three phases of ball motion; the ball path is in a straight line and has not yet encountered enough friction to begin its hook phase.


Refers to a ball reaction where the ball skids through the heads and midlanes of a lane and rapidly transitions from the hook phase to roll phase in backends. This is typically a violent and angular ball reaction.


The distance between the thumb and finger holes in a bowling ball.

Static Weights

The dynamic weight difference when comparing the finger region to the thumb region, the left side to the right side, and the top of the ball to the bottom.


Slow rev. rate/Low axis rotation a player that will play the lanes down and in covering very few boards.


The composition of the outside of the bowling ball. Also refers to the texture of the coverstock of a bowling ball.

Surface Roughness - Ra

The arithmetic mean of the peak to valley distances over an evaluation distance.

Surface Roughness - RS

The arithmetic mean of peak to peak distances of the local peaks in the evaluation distance.

Symmetrical core

An undrilled ball utilizing a core where the RG (radius of gyration) values of the Y (high RG) and Z (intermediate RG) axes of the ball do not differ by more than 5% of the total differential of the ball.

Symmetrical weight block

An undrilled ball utilizing a weight block where the RG (radius of gyration) values of the Y (high RG) and Z (intermediate RG) axes of the ball do not differ by more than 5% of the total differential of the ball.


In bowling terms, any pin or lane product not made of wood.


Three Piece Construction

A bowling ball constructed of three elements: the coverstock, the filler material and the high-density inner core.

Total Differential

The difference between the X (low RG) and Y (high R) axes values of any bowling ball.


The friction between an object and the surface on which it moves.


Medium rev. rate/Medium axis rotation a player that likes to belly the ball slightly, but prefers a fairly controllable reaction overall.

Two Piece Construction

A bowling ball constructed of two elements: the coverstock and the weight block. A modified two piece bowling ball has the same basic characteristics of a two piece ball, only the weight block has been modified to change the dynamics of the ball (i.e. dual density weight block).

Two-handed approach

This techniquie is used by both Jason Belmonte and Osku Palermaa. Both hands are placed on the ball and left on the ball throught the swing until release. At the point of release, a dominant hand releases the ball thereby being a one-handed delivery. Additionaly, the dominant hand is determined by the side of the body about which the ball swings.




A coverstock comprised of material from the polymer family which creates a hard, durable surface on the ball.


Vertical Axis Line

Also known as Perpendicular Axis Line (PAL). This is defined as the line perpendicular to your midline that continues through your PAP.


Weight Block

The dense inner component which is composed of various materials and shapes. This is considered to be the motor of the bowling ball. Differs from the core (see Core definition).