Bowling ball core · Roto Grip
Roto Grip Rocker A.I. Core
Symmetric Roto Grip core
A symmetric core with early rev-up and medium flare, built for heavy oil. 1 of the 2 balls with this core are in stock at BowlersMart.
- Symmetric
- RG 2.480
- Diff 0.050

Specs
RG AT 15 LB
2.480
Early rev-up
15% of the reactive and urethane balls we stock have a lower RG.
DIFFERENTIAL AT 15 LB
0.050
Medium flare
62% of the reactive and urethane balls we stock have a lower differential.
MASS BIAS AT 15 LB
None
Symmetric core
Symmetric cores have no mass bias marker to place when drilling.
| Weight | RG | DifferentialDiff | Mass biasMB |
|---|---|---|---|
| 16 lb | 2.480 | 0.054 | None |
| 15 lbUsed on this page | 2.480 | 0.050 | None |
| 14 lb | 2.500 | 0.046 | None |
| 13 lb | 2.580 | 0.047 | None |
| 12 lb | 2.640 | 0.037 | None |
Source: Roto Grip published specs, as listed on the Rockstar Amped product page. RG and differential change with ball weight; use the row for the weight you throw. The highlighted 15 lb row is the one used on this page.
Balls with the Roto Grip Rocker A.I. Core
1 of the 2 balls with the Roto Grip Rocker A.I. Core are in stock at BowlersMart. Same core, different covers: pick the cover for the lanes you bowl on.

Roto Grip Nanostar Pearl Reactive
Medium to heavy oil
Show 1 ball no longer available at BowlersMart
| Ball | Cover | First seen |
|---|---|---|
| Roto Grip Rockstar Bowling Ball | Roto Grip NanoStar Solid Reactive | January 2025 |
Where the Roto Grip Rocker A.I. sits
Each dot is a core in balls we stock. Cores close together roll alike; the cover and layout decide the rest.
Navy ring = a ball in your bag. Dashed ring = off this chart, or this same core.
Nearest cores, zoomed in
Navy ring = a ball in your bag. Dashed ring = off this chart, or this same core.
This core 1 Nearest cores Other cores
| Core | Brand | Shape | RG | Diff | vs this core |
|---|---|---|---|---|---|
|
|
Storm | Symmetric | 2.480 | 0.051 | RG 0.000 · Diff +0.001 |
|
|
900 Global | Asymmetric | 2.480 | 0.050 | Same RG and differential |
|
|
Motiv | Asymmetric | 2.480 | 0.050 | Same RG and differential |
|
|
Radical | Symmetric | 2.485 | 0.051 | RG +0.005 · Diff +0.001 |
|
|
Ebonite | Symmetric | 2.480 | 0.048 | RG 0.000 · Diff −0.002 |
|
|
Hammer | Symmetric | 2.480 | 0.048 | RG 0.000 · Diff −0.002 |
Matches use 15 lb RG and differential.
Drilling and tools
Turn on JavaScript to compare with your ball.Balls with the Roto Grip Rocker A.I. Core1 of the 2 balls with the Roto Grip Rocker A.I. Core are in stock at BowlersMart. Same core, different covers: pick the cover for the lanes you bowl on.
Questions bowlers ask
What is the RG of the Roto Grip Rocker A.I. Core?
At 15 lb the Roto Grip Rocker A.I. Core has an RG of 2.480. It ranges from 2.480 to 2.640 across the listed weights.
What is the 14 lb RG of the Roto Grip Rocker A.I. Core?
At 14 lb the RG is 2.500.
What is the differential of the Roto Grip Rocker A.I. Core?
At 15 lb the differential is 0.050. This is a symmetric core, so mass bias is not applicable.
Which bowling balls use the Roto Grip Rocker A.I. Core?
Roto Grip Rockstar Amped Bowling Ball, Roto Grip Rockstar Bowling Ball. 1 are in stock now.
How do the Roto Grip Rocker A.I. Core specs change by weight?
At 16 lb: RG 2.480, differential 0.054. At 12 lb: RG 2.640, differential 0.037.
How does the Roto Grip Rocker A.I. Core compare with my ball?
Type the ball you throw into the Compare with your ball box on this page. It shows the RG and differential side by side and saves your bag for every core page.
Sources and method
Specs. Roto Grip published specs, as listed on the Rockstar Amped product page, as published by the manufacturer.
Baseline. The baseline is 212 in-stock, published reactive and urethane balls. Plastic and polyester covers, 2-piece, 3-piece and pancake cores, missing covers and missing RG or differential values are excluded.
Percentiles. Percentiles are the share of baseline balls with a strictly lower or higher value; ties are not counted.
Nearest cores. Nearest cores are ranked by distance on standardized 15 lb RG and differential, with the same symmetric or asymmetric shape preferred among near ties (distance bands of 0.1).
Mass bias. Mass bias is compared among asymmetric balls with numeric mass bias only.
Updated. Catalog and page updated 2026-10-16.


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