Introduction: Tail Light for Bike Rack

I built this light for the bicycle rack on the rear of my car. It serves as an additional tail light and brake light.

Why: When I load the rack with several bikes, they often obscure the car's tail lights and upper brake light. This project helps make the car more visible, at day and at night.

- This instructable assumes you have the electrical skills to wire trailer lights.
- This instructable assumes your car is already wired with connectors for trailer lights.

Caution: Please check your local laws to ensure this project is street-legal where you live.

Acknowledgement: This was not my idea. I saw one on the road. I was so impressed, I built my own.

Step 1: Parts and Assembly

- Commercial trailer tail light assembly (I used an LED unit from Harbor Freight)
- Wire, shrink wrap, and connectors (from the trailer store)
- Wood, cable ties, string, goop glue, staples, paint (from the scap box)

- I cut a piece of wood to fit nicely on the bike rack.
- I attached the trailer light to the bottom of the wood two ways:
-- A glob of glue (Goop brand waterproof glue) between the light and wood
-- Two heavy cable ties (zip ties) around the light and wood
- I soldered a length of wire from the light to the trailer connectors.
- I stapled a length of string to each end of the wood.
- I painted it a visible color.

Step 2: Usage

- Place bikes on the bike rack.
- Place light assembly on the rear of the bike rack. Tie strings rack securely.
- Route electrical cable to car's trailer connector, and plug them in.
- Test lights.

Design alternatives
- Instead of strings, use strips of velcro to attach the light to the bike rack.
- Instead of one trailer light, use two (one on each side) and wire them as turn signals.

Unrelated to this instructable:
Notice the tennis balls in the last photo. They help make the rack more visible in daytime. This is useful if ever I forget to lower the rack in a parking lot. It also softens the blow when I walk past the rack and slam into one of the arms.

Step 3: Finished

Results: It may be wishful thinking, but I believe drivers follow a little less closely, both in daytime and at night.

Enjoy your new light, especially when you head out in the wee hours of the morning to some distant randonneuring event.