Originally Posted by
jrickards
My 700Cx35 Schwalbe Marathon has an ERTO of 37-622 which suggests that the 35mm tire (700Cx35) is actually 37mm tall (ERTO 37-622) which is apparent when you look at the tire because it has a slight aero-shape whereas my Michelin Pilot Sport (700Cx32) appears round and the ERTO bears it out, 32-622.
The ERTO measurement shows diameter and tyre
width, not height, and the width measurement is not always accurate.
Fitting a given tyre to a wider rim than it is designed for will reduce it's height as this will stretch the tyre across the rim and lower it's profile... tyre do tend to be about as tall / deep as they are wide when they are fitted to the right rims.