A light thread from a bit different angle...
Quick question: How many lumens would you recommend as minimum for the "be seen" flashing front helmet light? I use a Magicshine today, but would like to go to a USB rechargeable and reduce the weight and bulk.
I use the flash mode at all hours, day or nite, on my commute. Being seen is the point here.
Commander, UFO Bike
I'm not an expert by any measure, other than my own experience.
From what I've observed anything 40 lumens or better seems to me to be viewable in daylight in strobe mode. I'm currently using a Serfas Thunderbolt USB tail light, and it's a 40 lumen (red)light, and I've had a number people comment on it.
Of course, I'm a firm believer in the the more the better when it comes to lumens.
I have a Knog Boomer USB front and rear lights. They are both bright enough to be seen. However the front light's optics are not actually very "usable" as a light to ride by, but it surely is bright enough to be seen.