on a quick search; I find Tire Rack has the tires; they say that they do not come with a wheel, but they probably do sell the wheels too, which you might be able to find with a bit more poking around on their site Maxxis Spare Tire (tirerack.com)
Any local salvage yard is a good place to find a factory Ford spare that might not even have ever been used. I would think any 2015-18 Mustang should have the same exact spare tire in the trunk. Call around to a few and ask if they have any 2015 or newer Mustangs in their yard before wasting a trip there.
When I ordered my 2011 v6 with 18 inch wheels a spare wasn't offered as an option . I 'think' in 2013-2014 you could order one as an option. I ordered a spare from my dealer made for the 2005-2009 Mustang GT. We have the same brakes.....I had to order the wheel, the tire and the jack all separate, cost me around $500 . After all these years I have never had a flat tire I 'think' it was a $250 option for our 2013-2014 v6 Mustangs . I have seen spares for $150 'used' on E-Bay.........
A forum community dedicated to Ford Mustang owners and enthusiasts. Come join the discussion about performance, builds, modifications, reviews, engine swaps, classifieds, troubleshooting, maintenance, and more!