The way to get it perfectly tuned to your bike is to roll the bike N tire rotations and measure the length L. Then L/N is the length of one tire rotation and goes into the computer expressed as millimeters. Maybe use your driveway and mark the valve-down tire position with chalk, then roll the bike forward with your weight on it, and mark the valve-down position again after 5 tire rotations. Do this with your husbands's bike too, and you should be in sync.