Of course it is all down to ply rating of the tyres.
All I can say with any certainty is that the 45/60T float trailer supplied in 1964 was fitted with 24 ply tyres running at 110psi. The higher load/speed rating would presumably refer to tyre limitations (heat build up, hence the reduced trailer rating above a certain speed). If not then it would have a higher rating at the higher speed since the trailer frame is obviously not the limiting factor. It may well be that at the lower speed the trailer frame limits the capacity, so yes it is feasible the tyres could carry more.
What ply tyres the wartime Cranes tank trailer was fited with I have not a clue - I do know the tyres were available in a variety of plys, including 16, but maybe the 24 ply were not available until after the war.
I wonder what ply tyres the Dorset 24 wheel trailer has -if they are 24 ply, the greater rating is surprising. Date of this trailer? The build sheet would give the spec., maybe they should be 28 ply :cool2:
So it would seem pointless to speculate further on the theoretical capacity of the wartime Cranes trailer, but I would be interested to to know what the ultimate tyre limitation of the Rogers trailer was, did they not have a bit of a reputation for blowing them? :sweat: