Aggregate trailer mass

AGREGATE TRAILER MASS (ATM) - The total mass of the laden trailer when carrying the maximum load recommended by the manufacturer. This includes any weight transferred by the coupling when attached to the towing vehicle.

Simplicity suspension come in various weight carrying capacities.
In your case you have a 3500kg suspension pack.

Keeping the ATM at or below 3500kg give a manufacturer more tolerance when designing tow couplings, drawbars etc.

Coupling stengths for trailer ATM over 3500kg must be tested to and stamped with either the rated ‘D-value’ and ‘V-value’ or only the’ D-value’ in kN.

Hope this helps (hope I am correct)

Bob

That sounds about right, have not looked it up yet but if you calculate that out with AVM of 4182kg"Chev" and a ATM of 3300"BT" you would get 1845 gee long time since i did sums like this " not sure i ever did" would this be correct if so what does 1845 mean
Regards

I thought so, then when you get a tow hitch stamped 3.5, a tow ball stamped 3.5 and a tow bar stamped 3.5 beaing in mind the numbers we have used the saftey margin would appear to be 100%.
As i remember it at the time i looked into it the "D" rating i was told was only used for gov reg's for the general public type operations like ours, now that larger 4x4 and trailers are avalable this might change. imho the " D " is really of no use at all when you look at say the 3.5 A/T hitch from VC and also the Hyland 3.5 off Road hitch you woud think you be able to tow a lot more that they are rated for.
Regards