For Information. 5th Wheel trailers are classed as (quote) Motor Homes.. And not as most think caravans.. This comes about because of the way they are connected to the towing vehicle. namely 5th wheel.. and is not classed as a drawbar trailer, as with caravans/car trailers "A" frames etc. Which makes sense when you think an average weight of a tractor/truck/donkey/mule/artic or whatever you want to call the towing unit is about 10 tons, but the trailer and load which they tow can be 28 tons,, hence 38 tonners. I have used the figures on Lorry/Trailer weights as indication only.