Originally Posted by 2old

The battery has 120 watt hours (wh) and weighs one pound while the motor weighs seven pounds. "Normally", 15-25 wh per mile is a good rule of thumb, but pedaling gingerly, 170 pound rider, no wind, minimal hills, you could use 10 and realize 12 miles range (obviously, the range is "infinity" if you don't use the battery). I'm somewhat of a weight weenie too, but why not add a pound or two and double or triple the range? Check out Chas58's build (here or on ES if you want a super light bike).