I have no trouble at all seeing using a single Fenix L2D Premium flashlight mounted to my handlebar. On the brightest setting (turbo), it puts out 175 lumens. However, I generally run it on the 100 lumens setting for longer run time. Fenix flashlights are so inexpensive, that you could use two of them for about $125, and I can't imagine needing more light than that. I have a hill on my route where my speed tops 30 mph, and my Fenix provides enough light for me.