Bowling Glossary

Rack
The set of pins. If one is off spot it is called a bad rack and a new rack is set up.

Radius Of Gyration
This is the number of inches that the ball mass would be from the center of the ball if the mass was uniform and concentrated at one distance from the center. Imagine a hollow ball with a radius of 2.5 inches, the mass is concentrated at that distance from the center. Usually the ball will have a high and low RG because of the core not being round and uniform. The difference between the low and high RG is the RG differential. The number in the middle is the RG Ave.

Rail
The leave of pins that is a straight diagonal line. Includes the head pin and two or three other pins.

Reactive Resin
A type of coverstock that is made of urethane and a resin additive. Almost every high performance ball is made this way today.

Reading The Lanes
The way to get lined up by throwing shots. Seeing the reaction of the ball to the oil pattern in order to make adjustments to hit the pocket.

Refinish
To have a ball with many games sanded in order to smooth out all the nicks in the track and make it look like new.

Relaxed Fingertip
A type of grip where the fingers go into the first knuckle and the span is not quite as long as a normal fingertip grip. The hand is more relaxed when in the ball.

Release
The moment of truth in bowling. The point at which the ball leaves the hand and where the bowler knows if he threw it good or not.

Re-Rack
Getting a new set of pins for an upcoming shot by having the old rack swept off.

Rev Leverage
A ball layout where the pin is 4-1/2" and the center of gravity is 3-3/8" from the bowler's positive axis point. The CG in the thumb and positive quadrant of the ball and an extra hole is drilled 6 3/4" from the pin on a line through the CG.

Reverse Block
Oil is on the outside part of the lane with the driest part of the lane in the center. A difficult condition to score well on for beginners.

Reverse Pitch
The angle of the thumb is slope away from the center of the grip.

Revolutions
The rotation of the ball. A bowlers rev rate is the number of revs per minute. 400 to 450 being at the high end and 250-300 being the low end in pro bowling.

Ringing 10 Pin
When the 6 pin goes around the 10 on a good shot.

Roll Out
A ball that stops making it's move on the back end due to all of it's rotational energy being spent.

Rotational Energy
The spinning energy created on the ball by the bowler at release.

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