I have the EOS-bike on my helmet. It's a great lamp as a supplement to your bar mounted headlight. Looking into corners, fixing flats, reading road signs and cue sheets. If the bar mounted light should fail, I could get home with it if I pedal slower. I'd say about 10 to 13 mph. In the summer months, I leave the Velcro helmet mount attached and keep the EOS in my seat bag as a "just in case" light.