So the 50mm is lighter than the 40mm and the latter is the same weight as the 60mm ??

Surely, that in itself should raise some questions ?

I was wondering about that too so I looked into it a bit more, it seems the 60mm is narrower internally and externally than the 50mm which would make sense why their weight is similar. Apparently the rim of the 45mm wheel is the same as the gravel wheelset so potentially a heavier buildup? At some point the 50mm looked to have been revised and internal width increased from 21 to 24 which matches the specs of the cyclone so perhaps they are using the same rims here too.

Ordered the 50mm so will see how that goes