US Patent 9128465 Balance with hairspring, movement, and timepiece

To provide a timepiece balance with hairspring capable of changing the moment of inertia of the balance wheel without involving generation of a one-sidedness in weight. There is provided a balance with hairspring including a balance staff, and a balance wheel arranged around the balance staff, wherein there are provided a first rim constituting the balance wheel and having a guide portion configured to vary in the distance from the balance staff in correspondence with a peripheral direction around the balance staff, an elastic portion arranged so as to be slidable along the guide portion and capable of elastic deformation in the radial direction around the balance staff, and a second rim having a plurality of weight portions arranged in the peripheral direction.