Education Hub  /  Bowling Ball Cores  /  Bowling Balls by Mass Bias
ATTRIBUTE INDEX

Bowling Balls by MB

Mass Bias measures the strength of asymmetry in a bowling ball core. Higher MB values mean more aggressive flare and a sharper, more defined backend reaction. Symmetric balls have an MB of 0.000 to about 0.005. Anything above that is technically asymmetric.

By the BowlersMart Pro Shop Team. Last reviewed for the 2026 season.
AT A GLANCE
22
MB values indexed
3
Tiers: Low / Med / High
15 lb
Reference weight
USBC
Approved specs

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HOW TO READ MB

The 3 Mass Bias Tiers

Each MB value falls into one of three tiers. Knowing which tier you need narrows the search before you drill down to specific values.

LOW MB
0.005 to 0.015

Mild asymmetry. Smoother transition. Behaves close to a symmetric ball with extra core dynamic.

MEDIUM MB
0.016 to 0.025

Balanced asymmetry. The sweet spot for arsenal-building and versatile play.

HIGH MB
0.026 and up

Strong asymmetry. Sharp, defined backend break. Built for heavier oil and tournament conditions.

THE INDEX

All MB Values (Low to High)

Click any MB value to see every BowlersMart ball with that exact specification.

Jump to Low ↓Jump to Medium ↓Jump to High ↓
LOW MB (0.005 to 0.015)

Mild asymmetry. Smoother transition. Behaves close to a symmetric ball with extra core dynamic.

MEDIUM MB (0.016 to 0.025)

Balanced asymmetry. The sweet spot for arsenal-building and versatile play.

HIGH MB (0.026 and up)

Strong asymmetry. Sharp, defined backend break. Built for heavier oil and tournament conditions.

Other Core Attribute Indexes

ATTRIBUTE

By RG (Radius of Gyration)

Browse balls indexed by how early or late their core revs up.

Open RG index →

ATTRIBUTE

By Mass Bias Strength

Browse asymmetric balls indexed by how strong their backend break is.

Open MB index →

ATTRIBUTE

By Core Differential

Browse balls indexed by total flare and overall ball motion strength.

Open Differential index →

NEXT STEP

Know the MB you want? Get fitted at a pro shop.

Picking the right MB is one variable. Pairing it with the right layout for your PAP and rev rate is the next. Visit a BowlersMart pro shop for a certified fitting.