Bowling Ball Hardness

Research conducted by the United States Bowling Congress (USBC) Equipment Specifications staff showed environmental factors, especially temperature, can change the hardness measurement of bowling balls. Urethane shell balls are the most prone to variance, although reactive shell balls had variance as well.

USBC conducted a series of tests after a question was raised in the field related to approved urethane balls allegedly measuring below specification.

Click HERE for the Hardness Research Report published in 2019.

USBC took an additional step in February, testing the hardness of urethane balls being used at the 2020 U.S. Open. The goal of testing at the U.S. Open was to ensure all balls used in the competition met USBC specifications and to collect valid data.

Click HERE for the report of the bowling balls tested at the 2020 U.S. Open.

USBC continued its research of bowling ball hardness at the 2020 World Series of Bowling in advance of the 2020 USBC Masters. USBC felt it appropriate to not only continue to check the hardness of urethane balls, but also to investigate the hardness of used reactive balls.

USBC staff analyzed the research in order for the Equipment Specifications Committee to consider next steps.

Click HERE for the 2020 Hardness Research Report.

Click HERE for USBC's statement on Purple Hammer Hardness (March 1, 2022).

Click HERE for a letter from USBC Executive Director Chad Murphy on recent bowling ball announcements (April 1, 2022).

Click HERE for an FAQ on recent bowling ball announcements (April 1, 2022).