I wonder how many times I'll have to keep repeating myself. The goal of an aluminum frame is not always to save weight, when speaking of numbers. An aluminum frame is a lot more rigid than a steel frame and carries its weight lower. The geometry is different...so the number on the scale couldn't differentiate between the two...but the rider in the saddle can tell which is "lighter" right away because of the center of gravity being lower...it makes the bike FEEL light.
lots of people dont seem to understand that physic law