Bowling ball core · Hammer

Hammer Spheroid Core

Symmetric Hammer core

A symmetric core with early rev-up and medium flare, built for medium to heavy oil. 2 of the 13 balls with this core are in stock at BowlersMart.

  • Symmetric
  • RG 2.480
  • Diff 0.048
Hammer Spheroid symmetric core shape inside the ball

Specs

RG AT 15 LB

2.480

Early rev-up

Revs soonerRevs later

16% of the reactive and urethane balls we stock have a lower RG.

DIFFERENTIAL AT 15 LB

0.048

Medium flare

Less flareMore flare

52% 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.

RG How soon the ball revs up.Differential How much the ball can flare.Mass bias How asymmetric the core is.
Hammer Spheroid Core specs by ball weight
Weight RG DifferentialDiff Mass biasMB
16 lb 2.490 0.042 None
15 lbUsed on this page 2.480 0.048 None
14 lb 2.520 0.047 None
13 lb 2.560 0.030 None
12 lb 2.630 0.025 None

Source: Hammer published specs, as shown on BowlersMart’s original Hammer Spheroid 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.

3 balls on this core list different numbers
  • Hammer Dark Web Hybrid Bowling Ball: RG 2.510, diff 0.048, mass bias Not listed at 15 lb
  • Hammer Web Tour Edition Hybrid Bowling Ball: RG 2.470, diff 0.030, mass bias Not listed at 15 lb
  • Hammer Dark Web Bowling Ball: RG 2.510, diff 0.048, mass bias Not listed at 15 lb

Balls with the Hammer Spheroid Core

2 of the 13 balls with the Hammer Spheroid Core are in stock at BowlersMart. Same core, different covers: pick the cover for the lanes you bowl on.

Solid covers

Solid covers grip the lane soonest and suit heavier oil.

Hammer Hammerhead Bowling Ball

Hammer Hammerhead

Hammer Aggression Solid Reactive

Medium oil

Sale price $99.95 Regular price $249.95In stock

Pearl covers

Pearl covers go longer and turn harder at the end, best on medium oil.

Hammer Hammerhead Pearl Bowling Ball

Hammer Hammerhead Pearl

Hammer Aggression Pearl Reactive

Medium oil

Sale price $149.95 Regular price $249.95In stock
Show 11 balls no longer available at BowlersMart
More bowling balls with the Hammer Spheroid Core
Ball Cover First seen
Hammer Dark Web Hybrid Bowling Ball Hammer Aggression Hybrid Reactive March 2023
Hammer Bad Ass Bowling Ball Hammer Juiced Solid Reactive September 2014
Hammer Bad Intentions Hybrid Bowling Ball Hammer Juiced Extreme Hybrid Reactive September 2015
Hammer TNBA Rhodman Pearl Bowling Ball Hammer Juiced Maxx Pearl Reactive February 2018
Hammer Web Bowling Ball Hammer Aggression Hybrid Reactive October 2018
Hammer Web Pearl Bowling Ball Hammer Aggression Pearl Reactive June 2021
Hammer Web Aggressive Overseas Bowling Ball Hammer Aggression Bite Pearl Reactive September 2019
Hammer Web Tour Edition Hybrid Bowling Ball Hammer TourV1 Hybrid Reactive November 2019
Hammer Web Aggressive Bowling Ball Hammer Aggression Bite Pearl Reactive November 2019
Hammer Web Pearl Black Smoke Bowling Ball Hammer Aggression Pearl Reactive March 2018
Hammer Dark Web Bowling Ball Hammer Aggression Solid Reactive June 2022

Shop the 2 available balls with this core

Where the Hammer Spheroid 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 0.051Storm Catalyst Core, RG 2.500, diff 0.052Hammer 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 0.034DV8 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 0.054DV8 Duality Core, RG 2.480, diff 0.036Radical Outer Limits Asymmetric, RG 2.490, diff 0.051Motiv 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 0.047Ebonite Entity Core, RG 2.510, diff 0.052Motiv 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 0.036SWAG Judge Core, RG 2.490, diff 0.052900 Global Magna AI Core, RG 2.490, diff 0.044Roto Grip Rondure Core, RG 2.490, diff 0.052Columbia 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 0.047Motiv 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 High Rev Offset Core, RG 2.489, diff 0.053Hammer 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 0.054Roto Grip Defense AI Core, RG 2.490, diff 0.053Storm 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 0.052Storm Ignition Core, RG 2.490, diff 0.052Brunswick 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 0.053Ebonite Enhanced V2 Core (pictured: Ebonite Game Breaker 5 GB5 Bowling Ball)1Brunswick Zone Asymmetric Core (pictured: Brunswick Energize Bowling Ball)2Roto Grip Momentous A.I. Core (pictured: Roto Grip Attention Star S2 Bowling Ball)3Roto Grip Rocker AI Core (pictured: Roto Grip Rockstar Amped Bowling Ball)4900 Global Ellipse Asymmetric A.I. Core (pictured: 900 Global Origin EX Bowling Ball)5Motiv Overload (pictured: Motiv Evoke Hysteria Bowling Ball)6Hammer Spheroid Core (pictured: Hammer Hammerhead 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: Hammer Spheroid Asymmetrical Core Same family: Hammer Spheroid TE Core

This core 1 Nearest cores Other cores

Nearest cores to the Hammer Spheroid Core
Core Brand Shape RG Diff vs this core
Ebonite Game Breaker 5 GB5 Bowling Ball1Ebonite Enhanced V2 CorePictured: Ebonite Game Breaker 5 GB5
 Ebonite Symmetric 2.480 0.048 Same RG and differential
Brunswick Energize Bowling Ball2Brunswick Zone Asymmetric CorePictured: Brunswick Energize
 Brunswick Asymmetric 2.478 0.048 RG −0.002 · Diff 0.000
Roto Grip Attention Star S2 Bowling Ball3Roto Grip Momentous A.I. CorePictured: Roto Grip Attention Star S2
 Roto Grip Asymmetric 2.480 0.049 RG 0.000 · Diff +0.001
Roto Grip Rockstar Amped Bowling Ball4Roto Grip Rocker AI CorePictured: Roto Grip Rockstar Amped
 Roto Grip Symmetric 2.480 0.050 RG 0.000 · Diff +0.002
900 Global Origin EX Bowling Ball5900 Global Ellipse Asymmetric A.I. CorePictured: 900 Global Origin EX
 900 Global Asymmetric 2.480 0.050 RG 0.000 · Diff +0.002
Motiv Evoke Hysteria Bowling Ball6Motiv OverloadPictured: Motiv Evoke Hysteria
 Motiv Asymmetric 2.480 0.050 RG 0.000 · Diff +0.002

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

The Spheroid core has many of the dynamic properties found in some of the most successful core shapes in the history of bowling. Arguably, the most successful shape in history was used in the original Blue Hammer. This design was the founding premise behind our new Spheroid shape. The large spheroid was dynamically engineered with large grooves strategically placed along four quadrants on the perimeter in order to lower the RG, while maintaining a medium to high differential for ideal ball reaction. The Spheroid maximizes the friction enhancing properties as always with Hammer, we’ve poured the Spheroid core with Flex-Resin and the outer core with Carbon Fiber in order to create the hardest hitting and most durable ball possible.  

From Hammer’s description

Questions bowlers ask

What is the RG of the Hammer Spheroid Core?

At 15 lb the Hammer Spheroid Core has an RG of 2.480. It ranges from 2.480 to 2.630 across the listed weights.

What is the 14 lb RG of the Hammer Spheroid Core?

At 14 lb the RG is 2.520.

What is the differential of the Hammer Spheroid Core?

At 15 lb the differential is 0.048. This is a symmetric core, so mass bias is not applicable.

Which bowling balls use the Hammer Spheroid Core?

Hammer Hammerhead Pearl Bowling Ball, Hammer Hammerhead Bowling Ball, Hammer Dark Web Hybrid Bowling Ball, Hammer Bad Ass Bowling Ball, Hammer Bad Intentions Hybrid Bowling Ball. 2 are in stock now.

How do the Hammer Spheroid Core specs change by weight?

At 16 lb: RG 2.490, differential 0.042. At 12 lb: RG 2.630, differential 0.025.

How does the Hammer Spheroid 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. Hammer published specs, as shown on BowlersMart’s original Hammer Spheroid 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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