1. An old (or broken) spoke
2. 80-lb test fishing line
3. A needle-nose pliers
4. A small allen wrench or similar tool
Step 2: Making the Spoke
Using your needle nose pliers, bend a loop into the spoke about 3 inches from the threaded end.
Step 3: Finishing the spoke
Bend the spoke around itself for about two turns, and cut off the remaining portion. You should have something that looks like this.
Thread the spoke into the nipple two or three turns. Tie one end of the fishing line to the loop in the spoke, and make 5 loops of fishing line (10 strands total) between the spoke and the hub, threading it over and under the crossing spokes in the same way as the original spoke. Minimizing the slack in the fishing line at this point will make it easier to tension the spoke later on.
Tie a couple of half-hitches around the bundle of fishing line at the spoke end to finish it off. Cut off the excess line.
Insert your allen wrench or other tool into the loop on the spoke and thread it into the nipple. As you thread it in, the fishing line will twist to rapidly increase tension. Put the wheel on your bike and increase the tension until the rim runs smoothly past your brake pads.
You're ready to ride!
After 5 or 10 miles, the fishing line will stretch a bit, allowing the wheel to come out of true. Simply add a few more turns to bring it back into true, and continue riding.
The repair pictured here went about 200 miles and was still going strong!