[Tony Wheeler]

In the absence of any literature defining British WO load rating specs we're left to infer them from known vehicle types. In relation to CMP types they appear to be as follows:

Truck/Lorry (carried load):

8 cwt: SWB; 13" wheels
15 cwt: SWB; 16" wheels
30 cwt: SWB; 20" wheels; 2-spd transfer case (variants include Truck, 30 cwt, 4x4, AT Gun Portee; Lorry, 30 cwt, 4x4, Water) and: MWB; 16" wheels; 10.50 tyres; 2-spd transfer case (F30/C30 variants)
3-ton: LWB; 20" wheels; 2-spd transfer case


Tractor (towed load):

3-ton: 10.50 tyres; 2-spd transfer case (FAT, LAAT, F60T)

Note that for Tractors the wheelbase and wheel size are not stipulated, because they don't affect traction (towing capacity). A further spec applies to Artillery Tractors, namely winch.

As far as I'm aware the above specs hold true for all CMP variants except: F60S Bofors (Lorry, 3-ton, 40mm, Self-Propelled) which runs 16" wheels.

An apparent anomaly is the C8AX (NZ variant fitted with 16" wheels, making nominal load rating 15 cwt, and built on C15441 chassis) for which the expected designation would be C15AX. I'm inclined to suspect C8AX designation may be local misunderstanding, just like F60S designation seen on Australian F30 Ambulance.

On the question of LWB with 16" wheels, eg. F602L pictured above, I suspect these are rated for on-road use only, just like MCP vehicles. As such it would equate with the Dodge T110L5 (160" wheelbase, 16" wheels, 2-spd diff) which is rated 3-ton.

It's worth noting that design factors such as auxiliary springs, diff ratios, steering boxes, big balls v. small balls etc. do not define load rating - they simply reflect the way a particular manufacturer designs their range of 8, 15, 30, or 60 cwt. vehicles, as defined above. Which means the whole question of load rating is far simpler than it appears - once you figure out the rules!