A loaded descent is the hardest thing a trailer does
Most trailer wear is accumulated gently. The exception is a loaded trailer on a long downgrade, where the weight behind the tractor is pushing rather than following, and everything in the coupling and the running gear is working against that.
A trailer whose axles are already out of line is doing that while also being dragged slightly sideways, and the tires take the difference. It is also the condition in which a developing problem is most likely to become a visible one.
Which makes routes with sustained descents a reason to measure trailers rather than assume them. A trailer that has run those routes loaded for years has had more opportunity to move than a highway trailer with the same mileage.
What gets measured
Axle alignment to the kingpin, the relationship between axles on a tandem or tri-axle, and the condition of the suspension and mounting hardware.
Where a tractor keeps losing drives, a crooked trailer behind it is the candidate most often left unchecked, and heavy-duty truck alignment is here to settle it.
What the tires show
Wear that is opposite side to side on an axle: one edge down on the left, the other edge down on the right. A trailer running offset behind the tractor on a straight road. Fuel drifting on a route that has not otherwise changed. The same position being replaced every time.
The driver will not tell you. A trailer out of line transmits very little forward.
Brakes and tires on the same descent
Worth raising while a trailer is in. Brake heat on a long descent transfers into the wheels and the tires sitting on them, so a trailer that is both out of line and running tires at the end of their life is accumulating two problems in the same place.
The tire is the part that fails. The alignment is usually what got it there early.
About this store
The Colorado Springs store carries trailer tires and every other Purcell category, and is managed by Tyler Campbell. Denver and Loveland also align trailers.
See the national trailer alignment page for all 36 locations.

