Bowling ball core · Roto Grip

Roto Grip Rondure Core

The core inside the Roto Grip Rubicon line

An asymmetric core with mid-lane rev-up and high flare, built for medium to heavy oil. 1 of the 11 balls with this core are in stock at BowlersMart.

  • Asymmetric
  • RG 2.490
  • Diff 0.052
  • MB 0.011
Roto Grip Rondure symmetric core shape inside the ball

Specs

RG AT 15 LB

2.490

Mid-lane rev-up

Revs soonerRevs later

34% of the reactive and urethane balls we stock have a lower RG.

DIFFERENTIAL AT 15 LB

0.052

High flare

Less flareMore flare

72% of the reactive and urethane balls we stock have a lower differential.

MASS BIAS AT 15 LB

0.011

Mild asymmetry

MilderStronger

7% of the asymmetric reactive and urethane balls we stock have a lower mass bias.

RG How soon the ball revs up.Differential How much the ball can flare.Mass bias How asymmetric the core is.
Roto Grip Rondure Core specs by ball weight
Weight RG DifferentialDiff Mass biasMB
16 lb 2.480 0.050 0.012
15 lbUsed on this page 2.490 0.052 0.011
14 lb 2.530 0.052 0.009
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 Rondure 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.

2 balls on this core list different numbers
  • Roto Grip Gremlin Bowling Ball: RG 2.500, diff 0.058, mass bias 0.010 at 15 lb
  • Roto Grip Tour Dynam-X Bowling Ball: RG 2.470, diff 0.026, mass bias 0.010 at 15 lb

Balls with the Roto Grip Rondure Core

1 of the 11 balls with the Roto Grip Rondure Core are in stock at BowlersMart. Same core, different covers: pick the cover for the lanes you bowl on.

Roto Grip Gremlin Bowling Ball

Roto Grip Gremlin

Roto Grip V-R1 Pearl Reactive

Medium to heavy oil

Sale price $154.95 Regular price $249.95In stock
Show 10 balls no longer available at BowlersMart
More bowling balls with the Roto Grip Rondure Core
Ball Cover First seen
Roto Grip Tour Dynam-X Bowling Ball Roto Grip TourTrax Solid Reactive June 2023
Roto Grip Rubicon Bowling Ball Roto Grip eTrax-S20 Solid Reactive July 2020
Roto Grip Rubicon UC2 Bowling Ball Roto Grip eTrax-P20 Pearl Reactive December 2020
Roto Grip Rubicon EX Overseas Bowling Ball Roto Grip eTrax Pearl Reactive May 2022
Roto Grip Rubicon UC3 Bowling Ball Roto Grip Tour-ethane Pearl October 2021
Roto Grip Rubicon GT Overseas Bowling Ball Roto Grip MicroTrax Hybrid Reactive October 2020
Roto Grip Rubicon Extreme Overseas Bowling Ball Roto Grip MicroTrax P-20 Pearl Reactive June 2023
Roto Grip Rubicon Booster Overseas Bowling Ball Roto Grip ExtremeTrax Pearl Reactive March 2022
Roto Grip Rubicon Attack Overseas Bowling Ball Roto Grip Hyper Response Hybrid Reactive June 2022
Roto Grip Rubicon UC3 Trax Overseas Bowling Ball Roto Grip Tour Ethane Solid Urethane June 2022

Shop the 1 available balls with this core

Where the Roto Grip Rondure sits

Each dot is a core in balls we stock. Cores close together roll alike; the cover and layout decide the rest.

DV8 Larceny Core, RG 2.471, diff 0.028DV8 Renegade Core, RG 2.499, diff 0.040Track I-Core Gen4, RG 2.480, diff 0.053Brunswick Vintage Light Bulb Low RG Core, RG 2.568, diff 0.032Brunswick Dual Centric Core, RG 2.509, diff 0.047Ebonite Big Time Core, RG 2.500, diff 0.054Hammer Stacked LED Core, RG 2.545, diff 0.047Hammer Vindicator Core, RG 2.474, diff 0.053Radical Vexed Variant Asymmetric Core, RG 2.490, diff 0.045Radical Modified Intel Symmetric Core, RG 2.483, diff 0.032Motiv Affliction V2 Core, RG 2.480, diff 0.055900 Global Conduit A.I. Core, RG 2.590, diff 0.050Roto Grip GEM A.I. Core, RG 2.490, diff 0.057Hammer Obsession Tour, RG 2.469, diff 0.034Hammer Super Offset Core, RG 2.524, diff 0.053Hammer Gas Mask Core, RG 2.500, diff 0.058Ebonite Turbo Core, RG 2.510, diff 0.040Ebonite Centrex Symmetrical Mass Bias, RG 2.460, diff 0.056Motiv Excel Core, RG 2.550, diff 0.030Motiv Detonator Core, RG 2.470, diff 0.055Storm Solarion AI Core, RG 2.480, diff 0.054SWAG Insanity Symmetric Core, RG 2.520, diff 0.034SWAG Fusion Symmetric Core, RG 2.540, diff 0.036SWAG Watcher Symmetric Core, RG 2.510, diff 0.048SWAG Dragon Asymmetric Core, RG 2.480, diff 0.054SWAG Executioner Asymmetric Core, RG 2.500, diff 0.051Motiv Predator V2 Core, RG 2.470, diff 0.054Storm C3 Centripetal Control Core, RG 2.490, diff 0.029Roto Grip Rondure MaxD Core, RG 2.500, diff 0.058Hammer Vibe Core, RG 2.510, diff 0.042Hammer Aftermath Core, RG 2.520, diff 0.052Brunswick Alert Core, RG 2.478, diff 0.037Brunswick Rampart Core, RG 2.502, diff 0.051DV8 Collision Core, RG 2.462, diff 0.052Track MC2 Asym Core, RG 2.470, diff 0.046Radical Evil Eye Symmetric Core, RG 2.490, diff 0.046Ebonite Iron Fist V2 Core, RG 2.470, diff 0.053Radical No Doubt Symmetric Core, RG 2.480, diff 0.051Storm Surge Core, RG 2.580, diff 0.024Roto Grip Hyped UP Core, RG 2.500, diff 0.042Roto Grip Morph-Wing Core, RG 2.510, diff 0.051Brunswick Fury Core, RG 2.524, diff 0.038Motiv Sigma Core, RG 2.470, diff 0.047Roto Grip Hustle Core, RG 2.530, diff 0.030900 Global Blast AI Core, RG 2.470, diff 0.055900 Global Strobe AI Core, RG 2.510, diff 0.052Radical Guru Core, RG 2.500, diff 0.044Track I-CORE 3.0, RG 2.480, diff 0.056DV8 Unholy Core, RG 2.500, diff 0.051Brunswick Infinity Core, RG 2.521, diff 0.051Hammer Gauntlet Core, RG 2.501, diff 0.050Hammer Raw Hammer Core, RG 2.537, diff 0.038Storm Atmos A.I. Core, RG 2.530, diff 0.042Storm Booster Core, RG 2.540, diff 0.046Track Shuttle Core, RG 2.490, diff 0.038Brunswick Light Bulb Core, RG 2.524, diff 0.030Radical Sneak Attack Core, RG 2.540, diff 0.036Motiv Gear Core, RG 2.480, diff 0.034Hammer Huntsman Core, RG 2.470, diff 0.050Hammer Super LED Core, RG 2.632, diff 0.034Ebonite Enhanced V2 Core, RG 2.480, diff 0.048DV8 Dualistic Core, RG 2.490, diff 0.045Radical Vexed Asymmetric Core, RG 2.490, diff 0.036Motiv Quadfire Core, RG 2.550, diff 0.043Track Stealth Core, RG 2.480, diff 0.056Brunswick Tiered Hexagon Core, RG 2.540, diff 0.045Columbia 300 Piranha Core, RG 2.550, diff 0.043Storm Torsion AI Core, RG 2.470, diff 0.050Storm Element Max AI Core, RG 2.470, diff 0.055Storm Radius Core, RG 2.610, diff 0.020Roto Grip Rondure Tour X Core, RG 2.480, diff 0.034SWAG Unreal Core, RG 2.510, diff 0.047SWAG Craze Core, RG 2.520, diff 0.030SWAG Serpent Asymmetric Core, RG 2.510, diff 0.048Radical Torpedo Asymmetric Core, RG 2.480, diff 0.054Motiv Overload, RG 2.480, diff 0.050DV8 Duality Core, RG 2.480, diff 0.036Hammer Spheroid Core, RG 2.480, diff 0.048Motiv Apex Predator Core, RG 2.520, diff 0.055Brunswick Danger Zone Core, RG 2.501, diff 0.048Storm RAD-TQ Core, RG 2.560, diff 0.051Storm Velocity Core, RG 2.480, diff 0.051Hammer LED Resin Bowling Ball Core, RG 2.586, diff 0.027Epic Spark Core, RG 2.540, diff 0.049Motiv Hadron Dual Density Core, RG 2.500, diff 0.045Track Criterion ID Core, RG 2.490, diff 0.047Brunswick Zone Asymmetric Core, RG 2.478, diff 0.048Ebonite Entity Core, RG 2.510, diff 0.052Roto Grip Rocker AI Core, RG 2.480, diff 0.050Motiv Flux Core, RG 2.570, diff 0.015DV8 Mantra Core, RG 2.490, diff 0.047Hammer Gas Mask Low Diff Core, RG 2.500, diff 0.034Roto Grip RST Core + AI, RG 2.520, diff 0.055Motiv Impulse V2 Core, RG 2.550, diff 0.050SWAG APX V1 Core, RG 2.500, diff 0.042SWAG Fusion Core, RG 2.540, diff 0.036900 Global Magna AI Core, RG 2.490, diff 0.044Columbia 300 Pulse PowerCOR, RG 2.460, diff 0.045Storm Element Tour A.I. Core, RG 2.470, diff 0.035KR Strikeforce KR Launch Core, RG 2.530, diff 0.047900 Global Ellipse Asymmetric A.I. Core, RG 2.480, diff 0.050Motiv Halogen Core, RG 2.550, diff 0.037Storm C3 + AI Core, RG 2.480, diff 0.031Motiv Gear APG, RG 2.470, diff 0.036Radical Snapshot Symmetric Core, RG 2.520, diff 0.050Hammer Huntsman Tour Core, RG 2.472, diff 0.036Hammer LED Core, RG 2.650, diff 0.015Storm Inverted Fe2 Core, RG 2.570, diff 0.046Storm Capacitor Core, RG 2.570, diff 0.022Storm Velocity A.I. Core, RG 2.470, diff 0.053Storm Atomic Core, RG 2.480, diff 0.053Storm RAD-X Asymmetric, RG 2.480, diff 0.054Storm ID AI Core, RG 2.510, diff 0.055Hammer FAB Asymmetric, RG 2.550, diff 0.051Columbia 300 Shifter Core, RG 2.470, diff 0.050Radical Modified Intel Symmetric, RG 2.480, diff 0.032Columbia 300 Columbia Ricochet Core, RG 2.480, diff 0.054Storm Supercoil Core, RG 2.470, diff 0.053Storm Centripetal HD A.I. Core, RG 2.460, diff 0.056Hammer Modified Infamous Core, RG 2.567, diff 0.049Brunswick Ethos Core, RG 2.480, diff 0.053Hammer Hazmat Core, RG 2.470, diff 0.055Track Criterion MD Core, RG 2.500, diff 0.052Roto Grip Momentous A.I. Core, RG 2.480, diff 0.049Brunswick Portal X Core, RG 2.473, diff 0.054Ebonite Emerge Core, RG 2.510, diff 0.053Radical Katana Core, RG 2.500, diff 0.050900 Global Meditate LD Symmetric Core, RG 2.560, diff 0.027Columbia 300 Movement Core, RG 2.510, diff 0.053Storm Ignition Core (pictured: Storm Grand Gate Overseas Bowling Ball)1SWAG Judge Core (pictured: SWAG Judge Bowling Ball)2Radical Outer Limits Asymmetric (pictured: Radical Outer Limits Solid Bowling Ball)3Roto Grip Defense AI Core (pictured: Roto Grip Exit Red Overseas Bowling Ball)4Hammer High Rev Offset Core (pictured: Hammer 3-D Offset Assault Bowling Ball)5Storm Catalyst Core (pictured: Storm Alpha Crux Bowling Ball)6Roto Grip Rondure Core (pictured: Roto Grip Gremlin Bowling Ball)EARLY REV-UPMID-LANELATER REV-UPHIGH FLAREMEDIUMLOW FLARE2.442.482.522.562.602.642.680.0100.0200.0300.0400.0500.060RG at 15 lbDifferential at 15 lb← Revs up soonerRevs up later →More flare ↑Less flare ↓

Nearest cores, zoomed in

Hover or tap a dot for that core’s numbers. Click a dot to open its page. Drag to move around when zoomed in. The same RG and differential do not guarantee the same ball motion.

Same family: Roto Grip Rondure MaxD Core Same family: Roto Grip Rondure Tour X Core

This core 1 Nearest cores Other cores

Nearest cores to the Roto Grip Rondure Core
Core Brand Shape RG Diff vs this core
Storm Grand Gate Overseas Bowling Ball1Storm Ignition CorePictured: Storm Grand Gate Overseas
 Storm Asymmetric 2.490 0.052 Same RG and differential
SWAG Judge Bowling Ball2SWAG Judge CorePictured: SWAG Judge
 SWAG Asymmetric 2.490 0.052 Same RG and differential
Radical Outer Limits Solid Bowling Ball3Radical Outer Limits AsymmetricPictured: Radical Outer Limits Solid
 Radical Asymmetric 2.490 0.051 RG 0.000 · Diff −0.001
Roto Grip Exit Red Overseas Bowling Ball4Roto Grip Defense AI CorePictured: Roto Grip Exit Red Overseas
 Roto Grip Asymmetric 2.490 0.053 RG 0.000 · Diff +0.001
Hammer 3-D Offset Assault Bowling Ball5Hammer High Rev Offset CorePictured: Hammer 3-D Offset Assault
 Hammer Asymmetric 2.489 0.053 RG −0.001 · Diff +0.001
Storm Alpha Crux Bowling Ball6Storm Catalyst CorePictured: Storm Alpha Crux
 Storm Asymmetric 2.500 0.052 RG +0.010 · Diff 0.000

Matches use 15 lb RG and differential.

Drilling and tools

Drilling layoutsLayout guides for symmetric and asymmetric ballsDual angle converterTurn a pin to PAP layout into a dual angle layout

A drastic departure from our traditional symmetrical core or symmetrical weight block designs in the HP3 line, the asymmetrical Rondure Core was developed to increase overall ball motion throughout the lane without the aid of an added balance hole since those are now illegal in sanctioned competition. The starting point of this core was creating a low RG core design with a small intermediate split in order to emulate that symmetrical core with an extra hole type motion a lot of bowlers have grown accustomed to. Dynamically speaking, this core will rev up in the midline while providing more motion down lane than your traditional asymmetrical design. The smaller intermediate differential provides continuation closer to a symmetrical design. Thus, making this part the gap filler between asymmetrical and symmetrical core designs.  

From Roto Grip’s description

Questions bowlers ask

What is the RG of the Roto Grip Rondure Core?

At 15 lb the Roto Grip Rondure Core has an RG of 2.490. It ranges from 2.480 to 2.590 across the listed weights.

What is the 14 lb RG of the Roto Grip Rondure Core?

At 14 lb the RG is 2.530.

What is the differential of the Roto Grip Rondure Core?

At 15 lb the differential is 0.052. The mass bias is 0.011.

Which bowling balls use the Roto Grip Rondure Core?

Roto Grip Gremlin Bowling Ball, Roto Grip Tour Dynam-X Bowling Ball, Roto Grip Rubicon Bowling Ball, Roto Grip Rubicon UC2 Bowling Ball, Roto Grip Rubicon EX Overseas Bowling Ball. 1 are in stock now.

How do the Roto Grip Rondure Core specs change by weight?

At 16 lb: RG 2.480, differential 0.050, mass bias 0.012. At 12 lb: RG 2.590, differential 0.029, mass bias 0.008.

How does the Roto Grip Rondure 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 Rondure core page (2022), as published by the manufacturer.

Baseline. The baseline is 265 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.

Next lesson

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