I had the same situ with my Eco that has 17 in wheels and wondered about this myself. The Eco does not have a spare and the only one I found was a 16 inch. I figured this could only work if it is first off put on in the rear and it is only to get you to a place to have the regular tire/wheel fixed. The idea of spare tires anymore is a thing of the past. It is not like the old days where you used to "rotate the spare into mix" I don't even remember my last flat tire FWIW.