I posted this in the General Discussion but could also be in the DIY I guess. Mods feel free to move.
I recently finished this trailer for my work bike. It will also transfer to any other bike I have with a rack - pedal or motor. It's fashioned after an Oxtail Trailer (http://www.oxtailbicycletrailers.com/trailer.html
) but cost me a lot less as most of it is re-purposed parts from up in the attic. All I had to buy was some 3//4" EMT and a few nuts and bolts. I also debated various boxes for it and finally settled on a Stanley tool box with wheels and pull-out drag handle. It can be removed easily from the trailer frame and taken to a jobsite. That was $20US from Ace hardware but I figured it could be of use no matter what I decided to do with it.
The trailer has the advantage (without the box) of adding a piece of plywood for a flatbed deck. Or just use the frame and welded eyes to strap anything to it. I can also make a longer or shorter main trunk for it if the need arises to carry longer stuff. As it stands its a long drink of water at 11 ft. from front of bike wheel to rear of trailer wheel.
There is no suspension other than a hinged front pivot between the lower towbar and the main trunk. This connection is cushioned with a rubber fitting that remarkably absorbs quite a bit of shock and allows the trailer to "break" when it encounters a rough patch. I left myself an "out" though for a rear spring if needed -- but I don't think it will. The rear attachment to the fork is bolted together but also hinged. Although it is bolted rigid for now.
Unloaded I have to keep looking back to make sure it's still with me. It handles well loaded too. I've got about 100 miles on it so far and it really travels well. I've had about 25lbs. in it so far and all I notice is the motor isn't as peppy - DUH! The bike will still do 30MPH and climb my biggest bridges on my route with ease, but I normally cruise between 20-25MPH and its a good easy ride.
It was a fun build and something I really needed for my work bike. I got to finally use my HF flux wire welder and was having a blast with that although some of the welds were actually brazed with the O/A torch. So its probably not something someone without a welder could build unless using a LOT of nuts and bolts.
Between all the bike bags and the trailer I can make a day of it and carry everything I need and some I don't.