GORV - Digital Magazine Issue #37 | Page 29

RV FEATURE GTM VERSUS ATM Once and for all, Gross Trailer Mass (GTM) is not the relevant rating when purely determining the payload of a caravan or other trailer. Tare, ATM and GTM should be engraved on the van's compliance plate. This magazine – and many other sources of information – have been criticised by members of the vanning public for correctly stating that the difference, in kilograms, between Aggregate Trailer Mass and Tare is a caravan’s payload capacity. One correspondent even threatened to report us for falsely ‘advertising’ the payload capabilities of various caravans in our reviews. GTM is the relevant rating for assessing the amount of weight resting just on the wheels of a caravan. It is helpful in determining whether the group axle capacity, suspension and tyre ratings, are adequate. Unlike ATM, it does not include ball weight. So let’s all agree: ATM minus tare equals Payload Capacity. Okay? ‘OFFROAD’ MEANS ‘ANYWHERE’ ! A caravan might have fancy decals that imply an ability for the van to go anywhere the 4WD can. It might even claim to be an ‘offroader’. But what, exactly, constitutes ‘offroad’? A flat field that my grandmother’s old Volvo could traverse is technically offroad. Frankly, towed with care, common sense, and perhaps with a little preparation, caravans made for blacktop touring only shouldn’t fall apart in a bit of sand or gravel. The term ‘offroad’ as it applies to caravanning is quite subjective. What’s offroad to you might be a walk in the park to someone who has towed a rig on Cape York’s Old Telegraph Track. So when a manufacturer markets its caravan as ‘offroad-capable’, what does it mean? And what are the warranty limitations, not just of the caravan's structure but the various components, such as the suspension or stub axles? Never assume that ‘offroad’ means ‘anywhere’. Now this is what I'd call offroading. Speak to the manufacturer, read the fine print, and employ a healthy dose of common sense before dragging your caravan through that creek crossing or down that rutted track. / 29