WB>  Lay out a tape measure and roll the tire along it starting at the 
 WB> tire valve and ending at it.  That will give the circumference too.  
 WB> Measure that distance in Milimetres.
Not PRECISELY accurate as the weight on the tire will slightly deform it, 
making the circumference slightly less. A more accurate way is to paint a 
spot of paint on your tread and ride the bike, and then measure the 
distance between the marks on the pavement left by the wet paint. However, 
I have to admit that I follow the old "That looks close enough" method 
when I ride what I know is a certain distance and the odometer comes out 
okay. If you have a road with mileposts, it might be a good idea to ride 
around 10 miles on that road and see what it reads, calibrating from that. 
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 * Freddie 1.2.5 *  Unable to locate Coffee -- Operator Halted!
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