Calibrating distance on computers - long measured courses - surveyors wheels?
All,
I am curious how some of you are calibrating bike computers over longer measured course lengths - at least a mile if not 2-3+.
I have done the wheel count method over a measured distance. I want to say I used 200 feet, maybe 300 feet. On the 2 bikes I ride there is a slight variation in the distance over a routine ride I do. I find that a bit odd - if the wheel count method should be accurate then the numbers should line up closer than what they do.
That brings me to my question on calibrating over longer courses. Surveyors measuring wheels can keep track of distance while rolling, as opposed to stretching out a tape (even a long 100-300 foot reel tape) and resetting it. Plus - it would allow you to measure continuously however far you want to go. I think a lot of them max out at 9,999 feet. So you would be able to fit a mile in there at 5,280. Or, if you went further than 9,999 feet the counter would just start over. If you factor that in to the counter turning over - say the reading is 3,200. At 9,999 before that would be 13199 feet, or about 2.5 miles.
Just curious what others have done. My theory with the measured course is it would average out other inaccuracies that could be at play over a shorter distance - and that is what I believe the root of my mismatched distance readings is. They are close, but I notice they are different. I'd like to get them closer - and I don't know which one of the two is the most accurate.