Originally Posted by
Spoonrobot
This isn't true. Another poster just making things up.
There is specific variance in width and height tire manufacturers expect & allow. The variance due to rim design and width is well known. The variance due to casing type and design is also well known. There are no approximations, there is acceptable variance. You should buy the ETRTO and ISO standards and look for yourself.
A 40-622 tire that measures 39.5mm on a i25 rim at 30psi would be regarded as most likely undersized by the vast majority of tire manufacturers, today.
Now you are just being obtuse. Obviously you have haven't experimented with with different tire brands that are all labeled the same size. I have numerous times on my road bikes, mountain bikes, fat bikes and gravel bikes. And the tire width is all over the board. I could pull my Tufo 700 x 44 off of my i24 wheelset and throw on a different brand of the same size and I guarantee it will not measure the same as the Tufo.