Zero tire pressure continuation means that in the absence of air, the tires can continue to drive at a distance of about 80 kilometers, so as to ensure that the car can safely reach the maintenance site.
The spare tire doesn't do nothing, it must be maintained.
1. Regularly check the tire pressure. If a spare tire is replaced, it will not work as it should, and must be checked regularly.
The speed should not exceed 80 km/h. That's understandable since he's just a spare spare tire. Wearing shoes of different sizes for both legs can be uncomfortable and can cause damage to the frame and driveshaft if they are too light.