From http://craig.backfire.ca/pages/projects/shopping-cart-trailer
Before I bought a car I had to transport groceries on my bike, which was very tiring and hard on my back. I decided to make a trailer for my bike, using a shopping cart as a base.
The shopping cart, in 2003.
In 1996, when I was 11, I took sailing lessons at the CFB Trenton Yacht Club. One of the things we did once in a while was sail to a dock that was near a Tim Horton's in downtown Trenton. One day, I noticed that there was a shopping cart underwater, beneath the dock. My friends and I pulled it out, had some fun with it, and then threw it right back in.
In 2003, when I moved back to Trenton after having lived in Comox, BC for six years, I stopped by the dock and looked in the water. Sure enough, the shopping cart was still there.
Anyways, the summer of 2004 is when I got the idea to put the bike trailer together. I went to the dock again, and the cart was still there, of course. Armed with a long rope and a hook, my brother and I yanked it out in no time.
Fishing out the cart in 2004.
We brought the cart home and cleaned it off with a power washer. The smell was ridiculous, and it made such a mess on the driveway.
Making a huge mess while cleaning the cart.
Building the trailer itself was very simple. I cut off the entire undercarriage, welded on an axle for some wheels I had lying around, and then welded a tongue on.
Welding on the axle and tongue.
The mounting on the bike was just a bar of metal welded to some square tubing with a backing plate that bolted to it. For a universal joint, I used a strong rubber tube with clamps at each end. It worked like a charm.
The mount and universal joint on the bike.
At that point, the trailer was done and it worked perfectly. I certainly got a lot of looks when I biked around with it, but I didn't mind because it was so handy. It's a lot like seeing a guy walking around with a purse. It might look weird, but you can't deny the utility!
Riding around with the trailer attached.
The whole project cost me about $30, so I would recommend it to anyone that has access to an underwater shopping cart.
