One vendor says: Suitable for MITSUBISHI OUTLANDER with 16″, 17″, 18″, 19″ factory fitted wheels. This seems unlikely.
Another offers for a 225/55R18 original, a Space saver option of 165/80R17, which it says is a + 1.1% difference.
Overall diameter for the 165/80R17 = 27.4” INCHES. Width of the tyre = 6.5” INCHES
It also says:
The space saver spare wheel kit is designed to fit as close as possible to your original size tyres, aiming to keep the rolling diameter as close a match to your existing size. The difference can be up to 3% bigger or smaller, this is totally acceptable and please always remember this is only meant to be a temporary solution to enable you to get to a garage and not be stranded!
Anyone tried anything like this?