Originally Posted by
chaadster
I think very few lights in the North American market, at any price, have shaped lenses which would make mounting orientation problematic. The German STVZO standard does require a cut-off in the lens and are shaped/directional in that way, and would not work well upside down. There are few of those here in USA, though.
Thanks, chaadster.
Here's my light, the Bontrager 700 ion. If you look close you will notice the top of the beam is shielded farther out than the bottom. I've also seen other lights designed in this manner and there must be a reason for it. Surely this will cut off the top spill more compared to the bottom which has a shorter shield. Maybe the difference is small and only oncoming traffic can tell the difference, but it seems to me there must be some. I think I'll flip mine just for a test.