Originally Posted by
Choccy
That trick with the scales does not work as you muscles will take some of the weight. It needs to be dead weight to weigh it properly. Try a band round the rear brake lever and balance the bike on it's back wheel on the scales. I tried the scales trick before but got about 2lb differences when I used hanging scales.
Is this based on personal experience, or did you learn this in school? Draw a free-body diagram of the scale. Unless the scale is defective, the reading will represent the weight of the person and the bike!