The second attachment is a photo I took with the full-size spare in the hatch of my Volt. It is quite heavy and takes up a large amount of space. It current resides in my garage. However, if I go on extended drives over 100 miles I will secure the spare in the hatch area. Even with the spare in the hatch, there is enough space for small luggage bags for a few nights. I figure I can drive a long distance with the full-size spare that wouldn't be feasible with the compact spare. In my mind, the spare is like insurance, which I hope I don't need to use.If you have the time and safe area to work, if you blow a front tire you are better off swapping the spare onto the back axle, and using the good rear tire to replace the blown front tire... takes more time and effort, but it is far safer for driving.
Looking at the pictures I would much rather have a compact spare in the hatch area than a full size tire.
This is an emergency use only item without a TPMS sensor in it, just there to "tide me over" until I can repair / replace the blown tire. All we need is specs on the thread pattern for the threaded rod, and the already posted instructions to do our own "do it yourself" compact spare using ebay parts. I would like someone to confirm the available 225/70/16 spare fits without any rubbing at full lock to lock steering input so we know if it is another viable "do it yourself" option.
PS: All the factual info in this thread needs to be saved in a FAQ so I can find it again in 6 months or a year when I get a 2017 Volt!