In my effort to carry more things with my bike I decided to build a cargo trailer. It wasn't going to be a typical trailer though, I wanted something that was Heavy Duty, maybe something that could handle most household appliances. So I got started just like every other good home made bike trailer, with a pair of garbage picked wheels and a set of tires that were given to me for free.
Here is a quick run down of the main features of the trailer:
- Large 28"x41" deck
- Mounts with a quick release ball joint to any bike rack
- 1" square steel tube frame can accommodate up to 700c/29" wheels and tires
- 100mm drop out spacing to allow for most bicycle front wheels
- Space for tool box with tools, straps, and bungee cords
- Adjustable pulling arm to allow mounting to any bike
There is also a great post on the Utility Cycling blog about this bike move, Bike Move!
If you just watched the video your probably wondering, How much can I really tow with a bike? Well the company www.bikesatwork.com sells cargo bike trailers and has some great references on hauling large items on bikes. Check out the How much can I haul? page for a calculator on towing weight. They state that "...most people can comfortably pull 300 lbs (137 kg) with a typical mountain bike and cargo trailer..." Also check out these links for bike gearing and moving advice, Hauling Cargo by bike I have not purchased anything from this company but from the info they give and the pictures of their trailers in action I believe they sell a good product, but its just a little pricey.
So now that you see the potential behind a simple bike trailer, lets go build one!
NOTE: In order to use this bike trailer you must have a bike rack
Step 1: Tools, Materials, and Plans
- 4.5" Angle Grinder with cutoff, grinding, and sanding discs
- Drill Press with vice or C-clamp (not absolutely needed but makes drilling steel MUCH easier)
- Drill Bits size 1/4", 5/16" and 3/8"
- 3/8"-16 Tap
- Center Punch
- Welder ( I am currently using the 90amp flux core welder from Harbor Freight ~$100)
- Welding gloves and helmet
- Tape Measure
- 1" Square tube steel ( I got most of the steel for this trailer from an old BBQ grill and a bench press stand)
- 2" x 3/16" steel flat bar ~1ft long
- 1" x 3/16" steel flat bar ~1ft long
- 3/8"-24 threaded rod ~1.5" long (This is a fine thread size, and could come from an old bike axle, many of which are this thread size, or just cut off the head of a bolt of this size)
- QTY 2 - 3/8"-24 nuts (might also be able to use bike axle nuts)
- QTY 4 - 1/4"-20 x 2" long bolts with nuts and washers
- QTY 2 - 3/8"-16 x 1.5" long bolts with nuts and washers
- QTY 4 - 5/16"-18 Eye bolts with nuts and washers
- ~ 28"x41" piece of 3/4" MDF (This is for the deck of the trailer and you can use what ever you want for this)
- Quick Disconnect Ball Linkage (McMaster part #6058K34)
- QTY 2 - Bike wheels and tires ( I used 20" wheels, but the frame design allows for larger 700c wheels)
If your lacking some of the tools I mentioned, find a way to get them. Borrow them from your uncle, check out yard sales or search craigslist. These tools are pretty common and should be easy to find for cheap. For the welder, a MIG is going to be best for this project. It is completely doable with a stick or even a tig welder so just use what ever you have. If you have not welded before the 90amp flux core welder I'm using will be easy enough to learn with and at roughly $100 its by far the best bang for your buck. If you don't know how to weld check the Welding Guide and Learning to Weld from Phil B.
The attached pdf has detail drawings for the frame and the pulling arm, both parts are explained in the next few steps.
Step 2: Make the Dropouts
Now get out the ruler and sharpie and mark a point in the middle of each piece 3/4" from the end. Then grab your hammer and center punch, put the punch on your mark and hit it with the hammer. Don't Miss! Next put one of the pieces in your vice and center up the center punch mark with the drill bit in you drill press. Clamp everything down tight and put a dab of motor oil on the drill bit. This is not the ideal coolant method but it will save your drill bit from going dull. Set your drill press to the lowest speed possible, less than 500 rpm if you can. Then just drill the hole and repeat for the next three parts.
Next make a few marks from the edges of each hole to the edge of part. Then get out your grinder and cut from the hole to the edge of the plate. Once your done with all four dropouts you'll be a cutoff wheel master and ready to tackle the rest of the project.
Step 3: Weld up the Frame
If you don't have the luxury of steel tubing lying around you can buy tubing from a local steel supplier. You don't need bends at the corners but they do make the trailer look nice. If you have straight tubing you could bend it yourself with a Woodward Fab Pipe/Tube Bender
Step 4: Fabricate the Pulling Arm
Step 5: Trailer Platform
Step 6: Prepare you Bike Rack
Step 7: Accessories
- 1/2" and 9/16" wrenches (for the bolts and nuts used on the trailer)
- Bungee cords of various lengths and styles
- a set of ratchet straps (for holding the load)
- roll of tape (always seems to help when securing the load)
Step 8: Start Towing
The first thing I hauled with the trailer was the grill in the picture. I rode 7 miles on fairly flat roads with moderate traffic only had one issue. The garbage picked wheels really needed to be trued because there was a relatively harsh vibration around 12MPH. This is an easy fix.
If you have been thinking about building a bike trailer, stop thinking and just do it. You will be surprised at how useful your bike will become. If you are moving, you should defiantly consider a Bike Move. The best part about a cargo bike trailer is the looks that you get from people as you ride by. Everyone assumes that pulling things with a bike is just not possible, or at least impractical, but their minds will be blown when you cruse past. Have fun, ride safe and wear a helmet.