The tire size discrepancy could be due to the aspect ratio, maybe they're a little taller.
On the other hand, over the past couple of decades, I've noticed a tendency towards narrowing of newer tires compared to what they're replacing, and not just on bicycles. ![Roll Eyes :rolleyes: :rolleyes:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
![Wondering :wondering: :wondering:](/forum/styles/fusion/xenforo/smilies/wondering.gif)