[Tony Wheeler]

Originally Posted by Hanno Spoelstra

Load carrier trucks have a load rating, tractors do not - see the thread Is the FAT a 60cwt or 15cwt truck?.

Hanno, Tractors do indeed have a load rating, despite not being load carriers. I conclude therefore it refers to towed load, not carried load (as mentioned in my post above). Pretty obvious when you think about it but we overlooked it in the thread you mention.