lights always seem brighter when they are not on the bike. maybe because when you are moving you need to see further down the road than when you are standing in your office or backyard. when I first used my magicshine I thought dim would be adequate but as soon as I got one the road I left it on high and that's how I use it. from what I've read, 2 lights are ideal 1 on bar 1 on helmet and of course a rear strobe