Skip to content
The Encyclopedia of Horology

Glossary · Regulation

Adjustable mass balance

A balance wheel with movable weights for fine-tuning the rate without moving a regulator.

Explanation

Commonly used in high-grade watches (e.g., Patek Philippe Gyromax), these balances use rotating weights or screws to change the moment of inertia, allowing for precise regulation without interfering with the hairspring's active length.