Originally Posted by
Sy Reene
from the following, and supported by eg. Schwalbe's website, why do size equivalents go like this? :
40-622 = 700x40
38-622 = 700x38
37-622 = 700x35
32-622 = 700x32
25-622 = 700x25
etc.. ie. why does only the 37-622 tire have a different width when in the 700x## sizing (French sizing) of 35mm..? It only came up because I had ordered some 700x35 tires, and had a momentary concern when the box was labelled 37-622. I thought I had a return possibly on my hands.
ISO (x-622 etc) is the correct way. 700xY is the blast from the past. Just like we often say 28" wheels for wheels with rim tyre bead diameter of 622. Just like we say 29" wheels, for the same rim width, just with a fatter tyre mounted on it.
All explained in detail, with cross reference of old standards:
Tyre dimensions