Balancing is a specialist field and some basic insight into the subject can help improve product design, product quality, and production throughput.

Need to Work out A Balance Tolerance?

Universal Balancing’s Tolerance Calculator utilizes the ISO Balance Quality Grade G and combines it with part specific information to calculate a balance tolerance.

Iso Balance Quality G Grade

ISO Balance Quality G Grades are used to calculate balance tolerances in conjunction with the rotor weight and service speed (RPM).

G 40 40
  • Car wheels, wheel rims, wheel sets, drive shafts.
  • Crankshaft-drives of elastically mounted fast four-cycle engines (gasoline or diesel) with six or more cylinders4).
  • Crankshaft-drives for engines of cars, trucks and locomotives.
G 16 16
  • Drive Shafts (propeller shafts, cardanshafts with special req
  • Parts of crushing machinery.
  • Parts of agricultural machinery.
  • Individual components of engines (gasoline or diesel) for cars, trucks and locomotives.
  • Crankshaft-drives of engines with six or more cylinders under special requirements.
G 6,3 6,3
  • Parts or process plant machines.
  • Marine main turbine gears (merchant service).
  • Centrifugal drums.
  • Fans
  • Assembled aircraft gas turbine rotors.
  • Fly wheels.
  • Pump impellers.
  • Machine-tool and general machinery parts.
  • Normal electrical armatures.
  • Individual components of engines under special requirements.
G 2,5 2,5
  • Gas and steam turbines, including marine turbines (merchant service).
  • Rigid turbo-generator rotors.
  • Rotors.
  • Turbo-compressors.
  • Machine-tool drives.
  • Medium and large electrical armatures with special requirements.
  • Small electrical armatures.
  • Turbine-driven pumps.
G 1 1
  • Tape recorder and phonographs (gramophone) drives.
  • Grinding-machine drives.
  • Small electrical armatures with special requirements
G 0,4 0,4
  • Spindles, disks and armatures of precision grinders.
  • Gyroscopes.
1] w=2xn / 60-N / 0, if n is measured in revolutions per minute and w in radians per second. To simplify: Tolerance = Component Weight [kg] x Quality Grade x 9549 / Operational Speed [RPM]

2] In general, for rigid rotors with two correction planes, one-half of the recommended residual unbalance is to be taken for each plane.