Bowling ball core · Roto Grip
Roto Grip RST Core
The core inside the Roto Grip RST line
An asymmetric core with later rev-up, more length and high flare, built for heavy oil. Balls with this core are no longer available at BowlersMart.
- Asymmetric
- RG 2.530
- Diff 0.053
- MB 0.016

Specs
RG AT 15 LB
2.530
Later rev-up, more length
71% of the reactive and urethane balls we stock have a lower RG.
DIFFERENTIAL AT 15 LB
0.053
High flare
78% of the reactive and urethane balls we stock have a lower differential.
MASS BIAS AT 15 LB
0.016
Mild asymmetry
33% of the asymmetric reactive and urethane balls we stock have a lower mass bias.
| Weight | RG | DifferentialDiff | Mass biasMB |
|---|---|---|---|
| 16 lb | 2.520 | 0.049 | 0.015 |
| 15 lbUsed on this page | 2.530 | 0.053 | 0.016 |
| 14 lb | 2.550 | 0.053 | 0.016 |
| 13 lb | 2.570 | 0.032 | 0.010 |
| 12 lb | 2.590 | 0.029 | 0.008 |
Source: Roto Grip published specs, as shown on BowlersMart’s original Roto Grip RST core page (2022). 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.
Looking for a ball like your RST?
Balls with the Roto Grip RST Core are no longer available at BowlersMart. These in-stock balls have the closest RG and differential.

Hammer HK22 C2 Hybrid Reactive
Medium to heavy oil

Hammer HK22 C2 Solid Reactive
Medium to heavy oil

Brunswick Infinity Quest Pearl
Brunswick EVO Pearl HK22C Reactive
Medium to heavy oil

Motiv Propulsion MXV Pearl Reactive
Heavy oil

Roto Grip RST Hyperdrive Pearl
Roto Grip U-R1 Pearl Reactive
Medium to heavy oil

Radical HK22C+ Pearl Reactive
Medium oil
Balls with the Roto Grip RST Core
None of the 11 balls with the Roto Grip RST Core are in stock at BowlersMart right now.
Show 11 balls no longer available at BowlersMart
| Ball | Cover | First seen |
|---|---|---|
| Roto Grip RST Black Bowling Ball | Roto Grip eTrax ULTRA Pearl Reactive | November 2025 |
| Roto Grip RST X-1 Bowling Ball | Roto Grip MicroTrax Hybrid Reactive | October 2020 |
| Roto Grip RST X-1 Squad Overseas Bowling Ball | Roto Grip eTrax Pearl Reactive | April 2021 |
| Roto Grip RST X-2 Bowling Ball | Roto Grip eTrax Plus Pearl Reactive | June 2021 |
| Roto Grip RST X-2 Squad Overseas Bowling Ball | Roto Grip MicroTrax Solid Reactive | June 2022 |
| Roto Grip RST X-2 Pro Overseas Bowling Ball | Roto Grip Hyper Response Pearl Reactive | June 2024 |
| Roto Grip RST X-3 Bowling Ball | Roto Grip MicroTrax Hybrid Reactive | June 2022 |
| Roto Grip RST X-3 Squad Overseas Bowling Ball | Roto Grip MicroTrax Solid Reactive | December 2022 |
| Roto Grip RST X-4 Overseas Bowling Ball | Roto Grip MicroTrax Pearl Reactive | June 2024 |
| Roto Grip RST X-3 Pro Overseas Bowling Ball | Roto Grip XtremeTrax Reactive | October 2023 |
| Roto Grip RST Crash Overseas Bowling Ball | Roto Grip OptiTrax Solid Reactive | January 2024 |
Where the Roto Grip RST 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.
Same family: Roto Grip RST A.I. Core
This core 1 Nearest cores Other cores
| Core | Brand | Shape | RG | Diff | vs this core |
|---|---|---|---|---|---|
|
|
Hammer | Asymmetric | 2.524 | 0.053 | RG −0.006 · Diff 0.000 |
|
|
Brunswick | Asymmetric | 2.521 | 0.051 | RG −0.009 · Diff −0.002 |
|
|
Motiv | Asymmetric | 2.520 | 0.055 | RG −0.010 · Diff +0.002 |
|
|
Roto Grip | Asymmetric | 2.520 | 0.055 | RG −0.010 · Diff +0.002 |
|
|
Hammer | Symmetric | 2.520 | 0.052 | RG −0.010 · Diff −0.001 |
|
|
Radical | Symmetric | 2.523 | 0.050 | RG −0.007 · Diff −0.003 |
Matches use 15 lb RG and differential.
Drilling and tools
Turn on JavaScript to compare with your ball.Balls with the Roto Grip RST CoreNone of the 11 balls with the Roto Grip RST Core are in stock at BowlersMart right now.Show 11 balls no longer available at BowlersMartMore bowling balls with the Roto Grip RST CoreBallCoverFirst seenRoto Grip RST Black Bowling BallRoto Grip eTrax ULTRA Pearl ReactiveNovember 2025Roto Grip RST X-1 Bowling BallRoto Grip MicroTrax Hybrid ReactiveOctober 2020Roto Grip RST X-1 Squad Overseas Bowling BallRoto Grip eTrax Pearl ReactiveApril 2021Roto Grip RST X-2 Bowling BallRoto Grip eTrax Plus Pearl ReactiveJune 2021Roto Grip RST X-2 Squad Overseas Bowling BallRoto Grip MicroTrax Solid ReactiveJune 2022Roto Grip RST X-2 Pro Overseas Bowling BallRoto Grip Hyper Response Pearl ReactiveJune 2024Roto Grip RST X-3 Bowling BallRoto Grip MicroTrax Hybrid ReactiveJune 2022Roto Grip RST X-3 Squad Overseas Bowling BallRoto Grip MicroTrax Solid ReactiveDecember 2022Roto Grip RST X-4 Overseas Bowling BallRoto Grip MicroTrax Pearl ReactiveJune 2024Roto Grip RST X-3 Pro Overseas Bowling BallRoto Grip XtremeTrax ReactiveOctober 2023Roto Grip RST Crash Overseas Bowling BallRoto Grip OptiTrax Solid ReactiveJanuary 2024Where the Roto Grip RST sitsEach dot is a core in balls we stock. Cores close together roll alike; the cover and layout decide the rest.All coresSymmetricAsymmetricRoto Grip onlyAny brand900 GlobalBrunswickColumbia 300DV8EboniteEpicHammerKR StrikeforceMotivRadicalRoto GripSWAGStormTrack+−ResetZoom to this c
Questions bowlers ask
What is the RG of the Roto Grip RST Core?
At 15 lb the Roto Grip RST Core has an RG of 2.530. It ranges from 2.520 to 2.590 across the listed weights.
What is the 14 lb RG of the Roto Grip RST Core?
At 14 lb the RG is 2.550.
What is the differential of the Roto Grip RST Core?
At 15 lb the differential is 0.053. The mass bias is 0.016.
Which bowling balls use the Roto Grip RST Core?
Roto Grip RST Black Bowling Ball, Roto Grip RST X-1 Bowling Ball, Roto Grip RST X-1 Squad Overseas Bowling Ball, Roto Grip RST X-2 Bowling Ball, Roto Grip RST X-2 Squad Overseas Bowling Ball. 0 are in stock now.
Can I still buy a ball with the Roto Grip RST Core?
Balls with this core are currently unavailable at BowlersMart. Closest in-stock alternatives by RG and differential include Hammer Zero Mercy Hybrid Bowling Ball, Hammer Fallout Bowling Ball, Brunswick Infinity Quest Pearl Bowling Ball, Motiv Apex Jackal Bowling Ball, Roto Grip RST Hyperdrive Pearl Bowling Ball, Radical Snapshot Bowling Ball.
How do the Roto Grip RST Core specs change by weight?
At 16 lb: RG 2.520, differential 0.049, mass bias 0.015. At 12 lb: RG 2.590, differential 0.029, mass bias 0.008.
How does the Roto Grip RST 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 shown on BowlersMart’s original Roto Grip RST core page (2022), 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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