MikeS said:
From Tom’s blog - http://bmwi3.blogspot.co.uk/2014/02/bmw-i3-wheels-and-tires-what-you-need.html - None of the tires are runflats, and the i3 does not have a spare tire. What you do get is a can of "Fix-a-Flat" tire sealant and compressed air, which if used properly should get you at least as far as your nearest BMW dealer which will likely be the only place that stocks there rare tire sizes.
Fortunately, in the US at least, the tires are currently available at Tire Rack, too ($135/$149) for front/rear all-seasons).
My dealer's finance person, when trying to sell me a $2500 tire/wheel warranty, said they were run flats and $749 each, so as we've seen in many instances over the past several months, it pays to educate yourself and take EVERYTHING your dealer tells you about the i3 with a grain of salt unfortunately.