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Entry Angle: Part 3

USBC research shows where your ball should be to achieve the best angle

The first two articles of this three-part series included a discussion of how United States Bowling Congress testing has shown that six degrees is the optimum angle of entry into the strike pocket. In the previous article, we discussed the equation of a line drawn from the pocket back toward the bowler at two, four and six degrees. Finally, we concluded that we must know how far a ball will push past the end of an oil pattern to determine how to get our ball on one of these lines into the pocket and how noting where the ball comes out of the oil can be crucial to telling us what entry angle we have.

Research completed on USBC Sport Bowling patterns

During the past month, the USBC Specifications and Certification team (mainly research engineers Bob Roloff and Rory Holland and senior technician Jim Jaryszak) have been conducting research in the eight-lane testing facility in Greendale, Wisconsin to determine the average skid length, or “push”, pas the end of the oil pattern to the breakpoint. I was confident that if we used a USBC Sport Bowling pattern in our research, the push would be contingent on speed and rev rate, but wondered which would be more dominant.

Since we didn’t want the balls to see friction early – as can happen on a typical house shot – the test was performed on Sport Bowling lane conditions. We used two Sport patterns with the same amount of oil side to side but buffed out to distances of 37 and 41 feet. A group of 14 test bowlers with a wide range of ball speeds and rev rates provided the data by bowling on these patterns in our research center. Using the Computer Aided Tracking System (CATS), we could distinctly observe that shots rolled by our test bowlers pushed past the end of the pattern and further down the lane (in the oil) on the longer pattern, so I am confident we met our objective.

Data shows rev rate more important than ball speed

Let’s start with a look at the data. In Figure 1 (chart below), we see a summary of the results of this test.

Since I thought that speed would be the dominant factor in the amount of push past the oil line, the results were a little surprising to me. But once I thought about the fact that most higher average bowlers throw the ball from about 17 to a bit less than 19 miles per hour (a relatively tight range), it is clear that rev rate has a much larger variance among higher average bowlers (200-500 rpm).

Figure 1:
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Research data of test bowlers showing average speed and rev rate as associated with the “push” past the end of a USBC Sport Bowling oil pattern.

Figure 2:

Figure 2 shows the ball path of a test bowler with a lower rev rate (about 180) and slower ball speed (17 mph). This bowler was playing a typical “down-and-in” line where the ball crosses the second arrow and has a breakpoint at about 40 feet.

Another potential discovery (that I’ll think about during another sleepless night) is that a ball thrown with 350 rpm at about 18 miles per hour appears to be the optimum rev rate. Why? This preliminary research shows that at this rate a bowling ball seems to skid the proper amount to achieve optimum entry angle. As typical with research, more study is needed. Maybe this is why professional bowlers like Robert Smith and Michael Fagan felt like they needed to go to the Sarge Easter grip to cut down on their rev rate. Obviously, this will depend on conditions (lane surface, oil pattern, etc), but more often than not they seem to run out of room while trying to get the ball to push further down the lane.

This graphic shows the ball path of a test bowler with a lower rev rate (about 180) and slower ball speed (17 mph). This bowler was playing a typical “down-and-in” line where the ball crosses the second arrow and has a breakpoint at about 40 feet.

Another potential discovery (that I’ll think about during another sleepless night) is that a ball thrown with 350 rpm at about 18 miles per hour appears to be the optimum rev rate. Why? This preliminary research shows that at this rate a bowling ball seems to skid the proper amount to achieve optimum entry angle. As typical with research, more study is needed. Maybe this is why professional bowlers like Robert Smith and Michael Fagan felt like they needed to go to the Sarge Easter grip to cut down on their rev rate. Obviously, this will depend on conditions (lane surface, oil pattern, etc), but more often than not they seem to run out of room while trying to get the ball to push further down the lane.

Sport Bowling Tip of the Month

On the PBA Tour, creating strong entry angle is based on how much axis rotation a player can achieve. This is for two reasons. First, onthe PBA Tour, we play the end of the pattern where league players create entry angle by taking advantage of friction to the right. High rev rates are needed on Tour so the ball can slow down soon enough to create the optimum entry angle. Secondly, the PBA exempt player’ high rev rates create a laydown area much farther inside. Tommy Jones, Wes Malott and a few others can take advantage of playing further left because of their extremely high rev rates and axis rotation. Of course, the best players on Tour can adjust their speed, rev rate and axis rotation. Champions are crowned each week based not on who hits the pocket the most, but who can create the best entry angle.

How does this relate to amateur players? When you can throw your most comfortable speed and play the friction to the right, you are usually able to create a strong entry angle. But if you encounter a condition that dictates moving deeper on the lane, keep in mind that you may have to increase your axis rotation and/or decrease your ball speed to maintain or create optimal entry angle. Visit bowl.com to seek a USBC certified coach in your area who can help you improve those skills and make you a more versatile player.

Editor’s Note: Bob Learn Jr. is the Proprietor Relations Specialist for the United States Bowling Congress in Greendale, Wisconsin. The USBC certified coach has more than 20 years of experience on the Professional Bowlers Association Tour, where he owns five career titles including the 1999 U.S. Open.

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