Originally Posted by
chaadster
You don’t have to start the head unit? I think you do…and that the lights turn on when you start recording a ride, no?
In any case, I’m looking for lights which start themselves when the bike is in motion or at least when it gets dark, but I’d really prefer the former, as it appears the Cateye Reflex Auto is.
I think the head unit just has to be powered on. It tells me about cars approaching before I start a ride, eg when I'm calibrating my power meter. Most people aren't going to spend hundreds on a head unit and not use it, so it's almost functionally identical to what you're asking for in the sense that you don't have to do anything additional that you wouldn't do anyway.
I'm not telling you to buy the Varia, it sounds like the Reflex Auto may be better for your needs. The only reason I'm posting is to clarify how the Varia works. So that you or anyone else who finds this thread has good info to make your or their choice on.