Porsche 911 Carrera Owner's Manual page 149

f Select "Continue" and push the operating lever
forward.
f Select the appropriate tire size (18 or 19 inch)
and push operating lever forwards. A display
for confirming the selected tire size appears.
Note
This menu is displayed only if the tire pressures
are different for the approved tire sizes.
f Select "Continue" and push the operating lever
forward.
Instruments, On-Board Computer, Warnings
147