Geometric centerline of a vehicle is a line
Thrust line is the bisector of the total toe angle
Thrust angle is the angle formed by the
geometric centerline and the thrust line of an axle.
Tandem scrub angle is the angle formed by the
Tire wear from tandem scrub occurs at the
The same conditions that cause tandem scrub on
Misaligned trailer axles cause tandem scrub,
Alignment Angles Affect
tire wear, the effects on fuel consumption are less
easy to quantify. Fuel consumption is affected by
However, it is obvious that misalignment must
increase rolling resistance – and rolling resistance
is a major cause of fuel consumption.
Geometric Centerline Alignment can be used as a
reference from which to compute individual toe
angles. The Geometric Centerline of a vehicle is
established by placing a line from the midpoint of
the front axle and the midpoint of the rear-most axle.
The Geometric Centerline is not based on frame
rails or cross member reference points.
The alignment system will establish the