I have a loose correlation of a narrower fit on the dirt side versus the road. I started my shimano shoe collection with the RX8 gravel shoes which do seem a tad narrow. Then I decided to go shimano on road with the RC702 which are noticeably wider and roomier in the toe box. At the same time I ordered my wife a pair of the XC502 which are similar to my RX8 in their width.
I have the RX8 and RC902 (both same size but the 902’s are a wide fit) and the RX8 are still a much more comfortable fit in the width. Not sure if it’s material or discipline as one is gravel and the other road.
This is the shoe last details for Shimano. Models in the same category are designed with the same last and should fit similarly. Although, materials and other design choices could affect the final fit.
Yeah ity brilliant having narrow feet.
I feel at my most smug when i read a glowing review for a fantastic pair of cycling or running shoes where the reviewer says they are perfect other than being too narrow for some people