More complex than that, but i believe someone mentioned they tried it and it didn't make a significant difference. Apart from that actual width between manufacturers may differ, 190 is just what's stamped on the side, profile and actual width differ from manufacturer to manufacturer.
Exactly....l have a 200/55 Michelin RS at home and it is indeed 200mm wide....however, l also currently have a 190/55 Dunlop Roadsmart IV on my XR and it's 203mm wide.. go figure..🤔
Smithy.