Brochure

Tandem Axle Angles
Geometric centerline of a vehicle is a line
drawn through the midpoints of the front axle and
the rear reference axle.
Tandem scrub angle is the angle formed by the
two thrust lines of a tandem axle vehicle.
In the diagram below, misalignment causes the
tandem axles to work against each other
.
The steer axle must be turned to offset the “push” of
the axles and keep the vehicle moving straight ahead.
This causes ever
y tire on the vehicle to scrub.
Tire wear from tandem scrub occurs at the
leading edge of the steer tires, in a pattern called
“inside/outside” wear. For example, on the front
axle of this vehicle, wear would occur on the
outside of the left steer tire and on the inside of
the right steer tire. Tire wear would occur on all
drive axle tires.
Thrust line is the bisector of the total toe angle
of an axle. It represents the direction the axle
“points” compared to the centerline of the vehicle.
Thrust angle is the angle formed by the
geometric centerline and the thrust line of an axle.
Geometric
Centerline
Geometric
Centerline
Geometric
Centerline
Thrust
Line
Thrust
Angle
Tandem
Scrub
Angle
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