I mounted a Secula Plus taillight on my wife’s bike (fender mount). Instead of using 1/4″ relief grommets, I used Shimano’s DI-2 grommets. These grommet are split for easy wire threading and they lead the wire close to the fender – i.e. almost flush with the fender. The DI-2 grommets are oval shaped (6 mm X 7 mm) and require a little filing on the 1/4″ drill hole. The small wire hole in the grommet accepts the B&M wire supplied with the light but will not accept a coaxial wire cable.

To mount the light, I used a washer and Nylock nut instead of the supplied B&M nut. In addition, I place a thin leather gasket between the back of the light and the fender.