Join Date: Oct 2011
Location: currently NYC area, previously, Bay Area
Bikes: 1974 Raleigh Grand Prix
You might want to look for some super thin teflon coated wire wrap wire in the same color as your bike. Its almost invisible. You could use some lacquer or even superglue to glue it to the bottom of your top tube and it would be practically invisible. Or use the very fine gauge laquered wire they use for winding inductors, dynamos, etc. Magnet wire. Both are very fine, and solid, so they may need to be soldered on the ends for strength. You will need to strike the appropriate balance between durability and cosmetics. Another alternative is use the thinnest gauge of clear jacketed speaker wire you can find, and tape it with clear tape.