Originally Posted by Albany-12303
What I did was dab some white-out on my front tire and rode my bike down the length of my driveway. I then measured, with measuring tape, the distance between the dabs left on the ashphalt (about 3 measurments in all). I took the average and used this number as the circumference entered into the computer. This is the most accurate way that I can think of.
If your measurement was 1/8" off in a 50 ft driveway (how wide was the dab of white out?) you would be 1/4 mile off per 100 miles.
Does it really matter that much?