Do the 12 and 13 lb Roto Grip Perfect Gem use the same core as the 14 to 16 lb?
Roto Grip Perfect Gem Bowling Ball
Status:
Open Oct 08, 2026 - 04:45 PM
1answer
Staff Answer
Oct 08, 2026 - 04:45 PM
No. Roto lists different numbers for the lighter weights: the 15 lb Roto Grip Perfect Gem is 2.490 RG and .057 differential, while the 13 lb is 2.570 RG and .032 differential and the 12 lb is 2.590 RG and .029 differential. Those are the numbers of a different core shape, and the lower differential means less track flare, so the 12 and 13 lb roll smoother and hook less than the 14 to 16 lb. The product gallery shows both cores, one for 16 to 14 lb and one for 13 to 12 lb. The full table is on the product page.
Answer this question
View More Product Details
Roto Grip Perfect Gem Bowling Ball
What should I know about the Perfect Gem? • Asymmetric GEM + A.I. Core: low 2.49 RG and a massive .057 differential for heavy flare • All-new nano-free E-R1 Solid Reactive cover at a 2000-Grit Abralon finish • The cleaner, stronger, more continuous evolution of the Gem for medium-heavy to heavy oil
Buy Now
View all Roto Grip Perfect Gem Bowling Ball Questions & Answers
Share Your Own Experience & Expertise
We look to ensure that every question is answered by the best people with relevant expertise and experience, the best answers include multiple perspectives. Do you have relevant expertise or experience to contribute your answer to any of these commonly asked questions?
Add New Comment