Compare the two axles
On a tandem trailer, the two axles share the load and should run parallel to each other and square to the trailer. When one of them is out, the tires usually tell you which one before anything else does. The useful habit is to compare the axles against each other rather than looking at each tire alone.
Wear on one axle only. If the tires on one axle show scrubbing, feathering or rapid shoulder wear while the other axle's tires look normal, the worn axle is the likely suspect. An axle that is not parallel to its partner is effectively being dragged slightly sideways.
Wear on both axles, on the same side. If the tires on one side of the trailer wear faster across both axles, the problem may be the trailer's overall tracking rather than one axle.
Wear that matches on all four positions, evenly. That is what a healthy trailer looks like, and a useful reference when comparing others in the fleet.
Checking takes a few minutes at a yard inspection. Look across the tread of each tire, compare front axle to rear axle, and note anything that differs.
Why it is worth catching early
Trailer tires that are being scrubbed wear out early, and the tractor pulling the trailer has to correct for it. A trailer out of line can show up as wear on the tractor's steer tires, which then gets blamed on the tractor.
When to check
After suspension or axle work, after a hard impact, when a trailer joins the fleet, and when the tire comparison above shows a difference between axles. Align the tractor at the same visit with heavy-duty truck alignment where it is due, and set it up through a fleet account if you run several. The national trailer alignment page covers what the measurement includes.
Other stores nearby
In Salt Lake City, the Commercial & Consumer store and the Truck Tire Center also align trailers.
About this store
The Orem store runs eighteen services and is managed by Travis Olsen.
See the national trailer alignment page for all 36 locations.