Had some great weather today with no wind and temps in the 60's, so I pulled everything out of the trunk and put the Modern Spare tire in with outside facing down. The outside of the wheel is a 1/2" higher than the tire. I also measured the diameter by standing the tire up and putting a level across the tread, then measuring from the ground to the level. It is 25.5 inches when aired up to 63 psi.
Chevrolet Malibu spare tire kits. Light-weight alloy, long-range space-saver tire. Spec engineered for your Malibu. In Stock - Search Make/Model/Year
It will have to go in with the outside facing down, I tried it the other way and it holds the floor up slightly.
I checked for caliper clearance. The spare measures 6" from the lugnut to the ID of the rim, the same as the OEM wheel. There is plenty of room around the caliper with the OEM wheel.
The one thing I noticed immediately was the speed rating vs the printed 50 mph max on the tire sidewall. This is a direct contradiction since the speed rating "M" means 81 mph. This is also stated on their website.
In addition, each spare wheel is equipped with a durable space-saving tire with a DOT “M” speed rating indicating the tire is tested for a consent speed of 81mph. While it is wise to limit your speed to 50mph as some tire manufacturers state, we have chosen these “M” speed-rated tires knowing the tire’s strength and capability exceed that of normal use. This ensures that the tire is durable and well-built.
I wanted to test the air compressor included with the car. I lowered the air pressure to 40 psi, connected the compressor. You have to start the car for the aux power to be active and the compressor to run. It took about 1.5 minutes to from 40 to 60 psi. I suppose you could let all the air out if you wanted to put the tire in with it facing up, that might work.