Most minivans are capable of pulling trailers of roughly 3500 pounds GVW. That means the weight of the trailer and it’s cargo together. The downward force on the hitch (the trailer tongue weight) can vary with the type of hitch and the vehicle, but usually it will be somewhere around 200 pounds for a Class III receiver hitch. Always check with a hitch specialist before going over that. Sometimes the hitch will have it stamped on it, or on a label.
The type of trailer to buy (if you need one) for our minivan camper conversion depends on what you are going to use it for. If you are going to pile it full of gear that is weather proof anyway, like ATV’s and dirt bikes, coolers, and other things, then an open trailer might work for you. As long as you aren’t going to be where you have to worry about theft, it should work well.
For most traveling, though, an enclosed trailer works much better. It will not only keep things dry, but secure as well. For our minivan camper use, we suggest a trailer no bigger than what you need to get your “stuff” into it. Most small cargo trailers are eight feet long, but there are shorter ones available from some companies. If all you are going to carry is bikes and some extra gear, then a six-foot-long trailer would be sufficient. A motorcycle might require something slightly larger.
For economy’s sake both in buying and in pulling it around the country, don’t get one any bigger than necessary. The more weight you have, the more it will affect your gas mileage. Even the height of the trailer could be a factor in gas mileage if it catches too much wind over the top of the minivan.
The drawback to cargo trailers is that you have to store them somewhere. If you live in a condo with a one-car garage, that could be a problem. The alternative is what we have, a light duty folding trailer similar to what Northern Supply has, only we got ours form Harbor Freight. These trailers are bought as a frame, and you have to add your own plywood decking to them. They have stake pockets around the sides (usually two to a side). We made four-foot-high plywood sides for ours with 2 x 4 stakes that bolt into the stake pockets with lag bots. We added 2 x 2 corner braces so that the sides could be bolted together at the corners, and then waterproofed all the exposed wood. I notched the top of the sides so that we could put some 2 x 6 bows across the top in three places, with the center one being slightly higher than the ends. That provides support of the tarp that we put over the trailer and secure with heavy rubber trucker’s bungees on all sides. The rounded top sloped at both ends keeps rain from building up on it.
Granted, it’s not ideal. The back piece also bolts to the side pieces, and that makes it a pain to get anything in or out of the trailer. But at the time I built this, we were moving, and planned on being on the road for three days. We didn’t need to get in an out of it on a daily basis. I didn’t have time to find or make gate hardware, but that will have to be done at some point. Then I should be able to lift the rear gate out of the stake pockets to get into the trailer easily.
The other problem is security. With nothing but a plasticized canvas top on it held by bungees, someone could easily break into it. I have an idea for using a fiberglass tonneau cover from a full size pickup truck on it, but I would have to fabricate side rails that it could be mounted onto. Then not only would the back lift off, but it could have a door in it, too, and the top could raise up to provide full standing room inside the back of the trailer. And for long-term storage, everything would still come apart. These little trailers fold up and then you can roll them around on casters already mounted to the back of them, to put them up against a wall in your garage! The whole trailer could fold flat against a wall. For someone in a condo, where they don’t want campers or trailers parked outside, this would be the ideal set up!
That design for a trailer also gives me ideas for a new towable camper design that I will soon be working on after I get this project and book finished, so watch for that at a later date.