It never occurred to me that trailer tires could be overloaded to the point they would flatten on the bottom.
We were picking up a pallet of blocks with a reasonably sturdy two wheel trailer. The forklift driver said we needed to split the pallet because it was too heavy for the trailer tires. I told him to lower it slowly to see. Sure enough, the tires started to flatten to the ground. We split up the pallet into two loads.