Wherever you mount it, it needs to be oriented like a front light; turned through 90° about the long axis, as it is when mounted on a seat post or seat stay, it's completely dark at 90° off axis. Not that it's much better when mounted correctly, but at least there's some light emerging from the side
Wherever you mount it, it needs to be oriented like a front light; turned through 90° about the long axis, as it is when mounted on a seat post or seat stay, it's completely dark at 90° off axis. Not that it's much better when mounted correctly, but at least there's some light emerging from the side