COATS Series XR 1750, 1750-2D, 1750-3D, 1750-3DI Balancer - Manual (Page 39)

Important: Always read and follow the on-screen operating instructions. • 33
Video Balancer
Glossary of Terms
BDC - an acronym for bottom-dead-center, also
referred to as the 6 o’clock position.
Dynamic Balance - balancing a wheel using two
planes for correction. Dynamic balance means the
wheel is in balance when in motion about its rotational
axis. Also, a wheel is statically balanced when dynam-
ically balanced. However, a wheel that is statically bal-
anced is not necessarily dynamically balanced.
Hub Centric - refers to mounting and means the
wheel is centered to the vehicle by the center hole on
the wheel and the pilot on the vehicle axle. The maxi-
mum clearance between the wheel’s center hole or
bore and the axle pilot is between 0.0015 and 0.006
normally.
Inner Plane - the closest corrective weight location
from the balancer.
Lug Centric - refers to mounting and means the
wheel is centered by the studs and nuts mounted on
the axle of the vehicle. This is the least desirable way
to mount a wheel; very difficult to maintain the wheel
centering on the vehicle axle.
Offset Arm - pivoting arm that measures A & D
wheel dimensions.
A - distance measured from the balancer
(“0” on the offset arm) to the inner plane of
the rim (inner weight location).
D - diameter of the wheel at the weight
location, which is not always the same as
the bead seat diameter that determines tire
diameter.
W - width between the inner and outer
planes.
Outer Plane - farthest corrective weight location
from the balancer.
Static Balance - balancing a wheel with only a single
corrective weight or splitting two weights at the same
radial location.
TDC - an acronym for top-dead-center, also referred
to as the 12 o’clock position.
Weight Planes - the location for corrective weights.