Interesting. In my anecdata they match within a couple of mm. I have two bikes with Panaracer currently, one has Pasela PT, the other one is Gravel King, both 38-622. One measures 37.5mm, the other 36mm. That said I’ve only ridden relatively narrow tires over the last decade 25-40mm so it’s possible that the accuracy is higher in that range.
In any case X-Y with numbers like this really look like an ETRTO marking which according to the few tire manufacturers I’ve checked is how they size tires. Along with the traditional inch size conversion.
Even CST themselves correlate inch size to ETRTO size within 1-2mm.
What is it if not tire size?
Not sure, but every bike tire I have seen it doesn’t correlate to the size.
Interesting. In my anecdata they match within a couple of mm. I have two bikes with Panaracer currently, one has Pasela PT, the other one is Gravel King, both 38-622. One measures 37.5mm, the other 36mm. That said I’ve only ridden relatively narrow tires over the last decade 25-40mm so it’s possible that the accuracy is higher in that range.
In any case X-Y with numbers like this really look like an ETRTO marking which according to the few tire manufacturers I’ve checked is how they size tires. Along with the traditional inch size conversion.
Even CST themselves correlate inch size to ETRTO size within 1-2mm.