Originally Posted by
I_bRAD
If you sit on the bike and have someone measure that's accurate enough for me. Hell, even without someone sitting on it. I'm happy if I know I went around 100kms on a ride. I don't need to know I went 101.3kms.
+1 if you're worried about being totally upright, measure on both sides without moving and divide by 2.
the problem with the rollout method is you would have to keep a totally straight line.
And yes, I think this is a little bit of overkill, the chart with the computer is probably close enough.