Watch escapement runaway

      Once the balance wheel and pallet fork are removed, the gear train will rotate at high speed when wound because there is no resistance; this is known as "runaway". Since the wheels are driving and the pinions are driven, the speed multiplies through the gear train, reaching an extremely high velocity at the escape wheel. This is especially noticeable when the mainspring is near full power, often producing a "squeaking" sound. Prolonged high-speed runaway can cause rapid wear to the gear pivots.