Bayerd said:
I've just bought a computer, my tyre size is 38-622. Does anybody know how many mms the circumference is?
Get it on a the drive or a road if you don't have one, set the front wheel so the valve is closest to the road, mark a chalk malt, then roll it forwards one full rotation until the valve is next to the road again, make a chalk mark again, then measure the distance between the two.
