XCX Alloy and XCX Race Gravel wheels both use rims with a 24mm inside width and hookless bead sidewalls. 

Piedmont Race Alloy and Race Carbon Gravel wheels both use rims with a 26mm inside width and hookless bead sidewalls.

Width: All XCX Gravel wheels compatible with 32-57mm tire width. 38-47mm is recommended for optimal tire profile.

Pressure: Maximum pressure rating for XCX and XCX Race wheels is 60 PSI. As such, XCX and XCX Race wheels are NOT compatible with high pressure road tires or any tire requiring above a 60 PSI operating pressure. 

Hooked vs Hookless tire compatibility: We are not currently aware of any gravel tires on the market which require a hooked rim for compatibility. However, if you have concerns please reach out to the manufacture of the tire in question if you have doubts or questions about compatibility with hookless rims.