Introduction: How to Build a Bike Trailer
In this Instructable I'll show you how to build a bike trailer for moving anything around. I use mine for taking stuff to my allotment. I have also made a bracket to attach the trailer to my electric bicycle. This trailer provides more space than the boot of my Citreon C1 so it's really useful to me.
Disclaimer: I'm not responsible if anyone injures themselves after building a trailer identical or similar to this instructable.
Step 1: Make the Two Wheel Brackets
Firstly, we have to make the two wheel brackets, these brackets are just made from 4 pieces of wood each. Two are the same length as the width of the wheel, the other two are the same length and the length of the wheel. I kept the axles that were already apart of the wheels. unfortunately the axles where different diameters so on one of them I had to make a bracket by using some sheet metal, this strengthened the joint.
Step 2: Make the Body of the Frame
To make the body I just put two bars across the front and rear of the wheel brackets so that it was a square/ rectangular shape. I then added the front trail bar using two screw straight through the front cross bar. This however was weak so later on I strengthened it. This was temporary.
Step 3: Make the Frame Stronger and Better
To make the frame better I used the theory about triangles being the strongest type of shape, this is why I added two cross bars at 45 degrees to the trail bar and front bar. I then made the middle bit of the trailer stronger so that it was strong enough so that it could hold up an object/s with heavy masses. I did this by making an X shape in the centre of the trailer.
Step 4: Add a Bottom to the Trailer
Firstly I found a sheet of wood that I had in my garage. I marked out where the wheels will be and cut those bits out. Then cut the top triangular piece out until it fitted. After this I clamped the sheet to the frame to see where I need to add nails and the size of the top. I then glued the sheet to the frame and nailed it in place to secure it.
Step 5: Strengthen the Trail Bar and Frame
To add strength to the trial bar and the frame so that it can carry more weight. I did this by adding a sheet of metal and screwed it to the frame. This stage was very simple.
Step 6: Add Some Sides to the Trailer
Adding the sides is very important since stuff could touch the wheels and block them causing an accident and injury. I added the sides by screwing 4 poles upright on the inside of the wheels. I then added a back piece to keep it square. I added the front two poles as well. This was the first stage later I added more.
Step 7: Finishing the Sides
So this is my last step, in this I added two poles across the top of the vertical poles. I then added some side using some more sheet wood. I secured this using no nails glue again and a few panel pins.
Step 8: The Towing Hook
This tow hook was made from an old bit of aluminium alloy that I found in my garage. This wasn't part of my design so I didn't design this to last or work properly, just needed it for testing. It works by having one end cut and then bent all the way around; it then should be welded but I didn't have enough time for this. I drilled a hole vertically down this newly bend piece of aluminium with a 10mm drill bit. I used a 10mm bolt through this going upwards and then a nut onto to keep this from falling out.
The side of this I then drilled12mm which is the size of the rear axle. I should have attach this again at the front to secure it from tipping but I didn't want to drill or bolt onto the bike frame. It's a very basic towing hook. The trailer's front simply goes on top of the vertical bolt and then i add another nut on top of that to secure the trailer so that is can't come off. The one major issue with this towing hook is that if the bike falls over then the aluminium bends and can become weaker.
I hope this has helped some people with how I attached it. This is very basic and I wouldn't recommend building this towing hook however you can improve this in many ways to make it stronger and to stop it from breaking.