After the tandem has been slid
Most semi trailers have a sliding tandem: the axle assembly can be moved forward or back along the trailer to balance the load between the tractor and the trailer axles. Drivers slide it routinely, sometimes several times a week, and it is one of the most common places for a trailer to end up running out of square.
The tandem is held in place by locking pins that drop into holes along the rails on each side. When they are fully seated on both sides, the axles sit square to the trailer. When a pin on one side does not fully engage, or the pins are worn, or the holes have elongated over years of use, the tandem can sit slightly crooked, or shift under braking.
A trailer in that state tracks off to one side and scrubs its tires. The driver may not notice anything except that the tires on that trailer seem to wear out sooner than they should.
A habit worth building
After every slide, walk both sides and look. Each pin should be fully through the rail, and the release handle locked. Many drivers then give the trailer a gentle tug against the brakes to settle it, then look again.
When a trailer keeps wearing tires on one side, have the slider mechanism inspected as well as the alignment measured. Worn pins or rails will undo an alignment almost as soon as it is done.
Plan the visit
Fenton opens at 7:00 AM, so early drop-offs are easiest to turn around. Align the tractor at the same visit with heavy-duty truck alignment where it is due, and schedule several trailers through a fleet account. The national trailer alignment page covers what the measurement includes.
Other stores nearby
Washington and De Soto also align trailers.
About this store
The Fenton store runs seventeen services and is managed by Daniel Garcia.
See the national trailer alignment page for all 36 locations.