DOHHH why didnt I think of this before ?...wheel circumference

[Mangizmo]

Just fitting a £4.50 cycle computer, to get the wheel circumference just measure the tyre diameter and multiply by Pi (3.142) far easier than rolling between two points and measuring, never thought of that before !!

 

[JimK404]

The effective rolling diameter is less than the figure you've arrived at, because the tyre compresses. If you want to do it that way, maybe you could sit on the bike and measure from the axle to the floor?

Or get a bike computer that uses GPS - though probably not for £4.50

 

[FluffyChicken]

1st method is read the table they give you.

2nd is as you describe but not often used.

3rd and best and why they tell you is to measure a few rotations when sat one the bike as that takes into account the tyre deflection. Mostly.

BUT they're all pretty much the same that it makes no difference.


To above GNSS(gps) device can easily be out in distance and velocity (less so) depending on condition, building and forrest. Also it doesn't give true ground distance traveled.