RXT-G ACP BackTracker Steering system
Updated: 2012.03
2001 RXT-G - ACP LongRanger III
The LongRanger III is
equipped with AC
BackTracker steering
system.  This system is
designed to keep the
trailer directly behind
the tow vehicle
whether the vehicle is
moving forward or
backward.  The trailer
hitch and ball each
hold sensors that
determine the trailer’s
angle to the vehicle.
The wheels also hold  
sensors that determine
the trailer’s speed and
direction (forward or
reverse).  Between
these systems a PCB
controls the directional
inputs to a servo motor
which adjusts the
wheel pitch based on
inputs.  There is no
software involved in
the system.

The following pictures
show examples of
each of the
components of the
BackTracker steering
The PCB and various
pots to refine and
adjust the steering
The htich ball.  Note
the machining to
accomidate the ball
sensor four (4) pictures
Note the Blue cover on
the hitch assembly.  It
houses the
corresponding sensor
that reads the hitch
angle from the ball's
Here are the wheel
sensors.  One reports
speed and the other
reports direction back
to the PCB.
The following set of
pictures show the rack
and pinion (worm
gear) assembly.  This
assembly also holds
the servo motor and
The servo motor has a
white support rim
where a cap mounts to
ensure water tight
This is the interior of
the servo motor gear
The internals of the
rack and worm gear /
ball bearing system
are shown here.  This
design takes the
lateral pressure off the
servo motor and
allows smooth
controled operations.
The next two pictures
show the BackTracker
steering in operation.  
Note as the vehicle  
moves forward and the
front wheels of the
vehicle turn to the
right, the BackTracker
steering is
compensating by
steering the trailer to
the left; thus
maintaining the
trailer's position
directly behind the
Note the two (2) lag
bolts and lock nuts
under the 2x2"
reciever.  We added
these to eliminate all
motion from the hitch
coupling system.  
This ensures that the
hitch & ball remain
rigid to the vehicle's
frame at all times.  
With this modification
the trailer is perfectly
quiet behind the
vehicle and the
steering geometry
reads the precise
angle of the trailer.
A short video from AC
Propulsion showing
their RXT-G backing
up on the tzero.  Note
how the BackTacker
steering system
automatically keeps
the trailer directly
behind the vehicle.