The short answer

Treat the sunroof as a moving clearance zone. Before loading, verify tower placement, bar height, glass travel, seal compression, wind deflector contact, and the exact cargo position. If the rack maker says the sunroof must remain closed, follow that boundary.

Test the envelope

Part Check Stop if
Glass Full permitted travel with rack unloaded Glass or seal contacts hardware.
Deflector Opens and seats correctly Deflector hits a bar or tower.
Towers Correct fixed points and pads Tower sits on glass or a weak surface.
Cargo Load clears the opening Box, board, or strap can touch the glass.
Noise New whistle or vibration Sound comes with visible movement.

Keep fingers and loose straps away from moving glass. After adding cargo, do not reopen the sunroof unless the complete loaded setup remains within the instructions.

Limits

This guide does not approve a specific vehicle or rack. Exact manufacturer compatibility controls.