Read the tires axle by axle
A trailer with axles out of alignment tells you so in its tires, and the useful part is that the pattern often tells you which axle.
Walk the trailer and look at each tire's tread across its width, from the outside edge to the inside edge, then compare.
Both tires on one axle wearing on the same side. An axle that is not square to the trailer, pushing both its tires sideways in the same direction.
One axle worn, the other fine. On a tandem, an axle that is not parallel to its partner. The two axles fight each other, and one of them loses rubber in the process.
Scuffing or feathered tread on a whole tandem. Often a sign the tandem is scrubbing, especially noticeable on trailers that turn tightly in yards and on city streets.
Wear on just one tire. Possibly alignment, but just as possibly that tire's own pressure, a dragging brake or a bearing. A single tire on its own points somewhere different from a whole axle.
Photograph the tires, or note the pattern position by position. It turns a vague report of uneven wear into a clear starting point.
When to check
After a hard impact against a curb or a dock, after any axle, spring or hanger work, when a used trailer joins the fleet, and whenever the tire pattern above appears.
Plan the visit
Bring the trailer with its normal tires on, and mention what it hauls and how it is used. If the tractor pulling it is wearing its own tires unevenly, heavy-duty truck alignment can be done at the same visit, and worn trailer tires can be replaced with retreads through this store. The national trailer alignment page covers what the measurement includes.
Other stores nearby
The Salt Lake City Truck Tire Center and Ogden also align trailers.
About this store
This is the Salt Lake City Commercial & Consumer store, managed by Brian Morris. See the Salt Lake City page for how the city's listings divide the work.
See the national trailer alignment page for all 36 locations.