Build a bike trailer
Build a simple, safe bike trailer using plywood, wheels, a hitch, and tools. Learn measuring, fastening, and test towing with adult supervision.
About this activity
Build a simple, safe bike trailer using plywood, wheels, a hitch, and tools. Learn measuring, fastening, and test towing with adult supervision.
What you need
Step by step
- 1
Step 1
Measure and mark a rectangle 24 inches wide by 36 inches long on the plywood using the measuring tape and pencil.
- 2
Step 2
With adult help cut the marked rectangle out of the plywood to make the trailer base using the saw or jigsaw.
- 3
Step 3
Measure and mark two side panels 24 inches long by 6 inches high on the remaining plywood.
- 4
Step 4
With adult help cut out the two side panels from the plywood following your marks.
- 5
Step 5
Sand all cut edges of the base and side panels until they are smooth and safe to touch.
- 6
Step 6
Place a side panel along one long edge of the base and attach it using wood glue and wood screws so it sits flush and straight.
- 7
Step 7
Repeat Step 6 to attach the other side panel to the opposite long edge of the base.
- 8
Step 8
Turn the base over and measure to find the centerline and positions for your axle brackets about 2 inches in from each side then mark the bracket holes.
- 9
Step 9
With adult help bolt the axle brackets to the underside of the base then slide the axle rod through the brackets and tighten the nuts and washers securely.
- 10
Step 10
Mount the two bicycle wheels onto the axle making sure each wheel is seated properly then tighten the wheel nuts and spin each wheel to check they turn freely.
- 11
Step 11
Cut and sand a 24-inch wooden hitch arm then attach the arm to the front center of the trailer with a heavy bolt and nut so the arm can pivot and add a metal loop or carabiner at the arm tip for connecting to the bike with an adult chosen bike coupler or strap.
- 12
Step 12
With adult supervision check that every bolt and nut is tight then first pull the trailer by hand and finally have an adult safely test tow the trailer behind the bike at slow speed before using it for cargo.
- 13
Step 13
Share a photo and a short story of your finished bike trailer on DIY.org
Fun facts
How do you build a simple kid-friendly bike trailer?
Start by planning size and capacity, then measure and mark plywood for the bed and sides. Cut pieces and build a boxed frame, reinforcing corners with L-brackets. Fit an axle and attach wheels securely using bearings or hub bolts. Mount a sturdy hitch arm that clamps to the bike's rear axle or seatpost adapter, using heavy bolts and a swivel joint. Sand, seal, add straps and test tow slowly with adult supervision, checking fasteners and balance.
What materials and tools are needed to build a bike trailer?
You'll need a plywood sheet for the bed and sides, 2 wheels with axle or a prebuilt axle assembly, metal hitch coupler, bolts, nuts, washers, L-brackets, wood screws, and a measuring tape. Tools: saw, drill, wrench set, screwdriver, sandpaper, clamps, and a file. Finish supplies: paint or weather sealant, straps or cargo net, reflectors and a safety flag, plus helmets and eye protection for everyone.
What ages is building a bike trailer suitable for?
This building activity suits different ages: children aged 10–16 can help with measuring, marking, sanding and basic assembly under close adult supervision. Teens 14+ may operate power tools with guidance. Younger kids (5–9) can participate by choosing colors, attaching reflectors, and loading cargo while adults handle cutting, drilling and hitch work. Always supervise tool use and towing; adults should complete critical fastenings and safety checks.
What safety precautions should we follow when making and using a bike trailer?
Safety first: always wear helmets, eye protection and gloves during building and towing. Keep trailer weight within a safe limit—test with light loads before carrying children. Secure cargo with straps, use a flexible hitch, and add reflectors and a high-visibility flag. Check bolts, tires and hitch before every ride. Tow only at low speeds on quiet, flat routes away from traffic. Adults must supervise testing and maintain a functional brake on the towing bike.
Watch & Learn
Need help?
What can we use instead of plywood, a jigsaw, or a commercial axle if those are hard to find?
If full sheets of plywood or a jigsaw are unavailable, have an adult cut two 1/2-inch plywood sheets and glue+ screw them together for the base and use a handsaw for cuts, and substitute a threaded steel rod or salvaged bike axle plus recycled bicycle wheels for the axle and wheels in step 9.
My wheels wobble or won't spin after assembly — which steps should I re-check and how can I fix it?
If wheels wobble after step 9, re-check that the axle brackets in step 8 are bolted square to the centerline, confirm wheels are seated properly with correct washers and tightened nuts, add thin shims or loosen and re-seat the wheel, and lubricate the axle so they spin freely.
How can we adapt tasks in these instructions for younger kids versus older kids or teens?
For younger children have an adult pre-cut the base and panels and let them do measuring (step 1), sanding (step 5), and decorating, while older kids can perform supervised cutting and bolting (steps 2 and 8) and teens can assemble the axle, hitch (steps 9–11), and handle final testing.
What are simple ways to extend, improve, or personalize the finished trailer from these instructions?
After sanding and assembly, personalize by painting the side panels, adding reflector tape and cargo straps to the base, installing a padded liner for cargo comfort, or swapping the step 11 bolt-on hitch for a quick-release coupler and a removable tailgate.