Bowling Ball Delivery Angle

bowlingball.com, Originally Posted: 4/6/2013; Updated: 5/3/2023

The angle your bowling ball leaves your hand and contacts the lane surface as your ball travels to the dovetails (just beyond the bowling arrows) is measured against the line created by the boards of the lane and is known as your delivery angle.
A bowling ball delivery angle can vary as many as 12 degrees.
Typically, straight ball bowlers “point the ball" to the pocket from an outside line.
The "stroker" type player uses more of a down and in delivery angle.
The stronger delivery styles, such as "power players", hook the ball a great deal on the back end but also use a wider delivery angle than the aforementioned players.
A player who delivers the ball with the center of the bowling ball first contacting the lane on the 10 board, just beyond the foul line and rolls the ball over the 2nd arrow (10 board located at the bowling arrows) would be said to have a zero degree delivery angle.
We base other delivery angles from a zero degree measurement.
The delivery angle can be measured at a distance after the bowing ball has traveled about 15 or 16 feet of distance from the foul line. This distance of travel compares to a similar distance a ball travels from the break point to the pocket and is known as the angle of entry.
A “straight ball” bowler pointing the ball from the 7 board and crossing the 2nd arrow would be said to have an approximate negative two degrees of delivery angle, again accounting for an approximate travel distance of about 15 feet.
Continuing, a “stroker” type player, who delivers the ball with little hook, would have an approximate delivery angle of 2 degrees if the "stroker" player releases the ball on the 13 board and crosses the 2nd arrow using a 3 board “swing” angle.
The “tweener” player, who hooks the ball more than a “stroker” player, might use a delivery angle of 3 or 4 degrees “swing” based on releasing the ball on about the 14 or 15 board beyond the foul line and crossing the 2nd arrow, again traveling the same approximate distance of about 15 or 16 feet of travel.
The power players can use a wide delivery angle before contacting the 2nd arrow, perhaps as many as 8 boards, by releasing the ball on the 18 board just beyond the foul line and crossing the 2nd arrow. This measurement might be in the range of 4 to 6 degrees of delivery angle. Normally, however, the power player uses a sighting target inside the 2nd arrow when employing a wide delivery angle.
Typically, the further of an inside line a player uses, the more delivery angle is used.
If a power player releases the ball, as another example, on the 33 or 34 board beyond the foul line and crosses the 23 board at the arrows, the delivery angle is much wider and is approximately 7 or 8 degrees of angle.
Here is what is extremely important to know when trying to visualize a delivery path angle: the USBC (United States Bowling Congress, the governing body for the rules and regulations for the sport of bowling) has publicized that a pocket strike occurs at board 17 to 18 board with an entry angle (the angle created between the break point of the lane and the boards running parallel up the lane) being optimum at a range of 4 to 6 degrees angle of entry with pin carry being optimum at 6 degrees angle of entry.
In the middle section of the lane, about the middle 20 feet of lane, the ball moves into the 2nd phase of ball motion known as the hook phase. In the mid-lane, the ball will begin hooking and loses the delivery angle almost entirely before moving into the 3rd phase of ball motion, the roll phase.

The roll phase occurs on the back end of the lane when the bowling ball changes direction at the break point and travels in the opposite direction from the delivery angle.
The angle the ball travels from the break point to the pocket, the angle of entry, combined with the delivery angle and the hooking angle in the mid-lane, gives the appearance that a ball actually hooks far greater number of degrees out and back than one would think.
It is not critical or extremely important to know your precise delivery angle or angle of entry. No ball motion study to date stresses knowing the combined angles a ball travels in the three phases of motion as a useful tool.
One certainty is that if a bowler uses too much delivery angle and does not have a strong enough of matching rev-rate, the ball may not react as well on the back end of the lane because of an improper alignment and delivery path.
It is advised, however, that you know your delivery path alignment strategy so you play the lanes according to your delivery style and matching with the oil condition applied on the lane surface.
Don’t get caught up in the minutia of science, but rather use sound alignment and adjustment strategies. Play the lanes smart and you can enjoy many scoring successes.