The Surly Bill and Ted trailers fill the gap between smallish cargo trailers (that can't carry more than, say 150 pounds), and cargo bikes (which can carry a lot of weight, but can be difficult to ride and store -- in addition to being another bike you have to own). Haul up to 300 pounds on this 63 by 24-inch load bed. (The Ted is still huge, but about half the length.)
Bill and Ted also fill the gap between mass-produced purpose-built trailers that aren't easy to customize, and large DIY custom trailers that get the custom functions right (hot dog stand, mobile home, etc.) but don't quite get the trailery parts right. These trailers are a solid platform for building whatever you envision a bike trailer can do -- be it utilitarian, or all-out weird.
The beds have threaded eyelets for bolting down decking, corner posts, or creating other custom accessories using readily-accessible materials from your local hardware store, lumberyard or home improvement store.
The beds and hitches of Bill and Ted are constructed with TIG-welded 4130 CroMoly steel plus 304 stainless steel hardware for corrosion resistance and a long life.
Sixteen-inch wheels keep your cargo low to the ground for better handling, and tip resistance. Surly designed the hubs to meet the requirements of this frame. The rims are double-wall with stainless eyelets. The spokes are stainless steel, radially laced.
And then there's the hitch. Regardless of the configuration of your bike frame -- full-suspension frame, disc brakes, rear racks, fenders, 20-inch wheels, 29-inch wheels -- the hitch will probably fit your bike. Instead of clamping to the bike's frame tubes, it attaches using a proprietary axle skewer or thread-on axle nuts. The hitch adjusts to keep the load bed level no matter your wheel size, to align the center line of the trailer to the center line of the bike no matter your hub width (120 to 145mm).
The frame is a solid unit constructed of welded CroMoly steel square tubes.
The wheel covers are load-bearing, and keep cargo from shifting into the spokes. Mount fenders and spoke guards (not included) to the threaded bosses, on the wheel covers.
The hitch is highly adjustable to fit most types of bikes and a wide variety of wheel diameters and hub widths.