Should I put a toy spare in the trunk of my Miata, or use the OEM sealant kit? Tires are low profile, aluminum rims.
Get a doughtnut spare.
With the low profile tires, if you get rim damage or if the sidewall of the tire is damaged a Fix-A-Flat won’t work.
It might depend on where you are driving it. How far from tire stores (that have that size), and suppliers that have replacement wheels, will you be?
The biggest question would be, can you find a doughnut spare tire that will fit in the trunk AND clear the brake calipers?
Carry the correct size spare or call a tow truck…
What size came with the Miata? Use that.
I assume you have an NC or 3rd generation Miata, 2006 on, since that’s when Mazda did away with the spare. The donut from a 3rd generation RX-7 will fit the NC hub. See the thread here. Scroll down to the last post.
Also, there are a number of posts on the forum at www.miata.net discusing other donuts that will fit. Apparently, the donut from the RX-8 and Mazda 3 will also fit. Take a look here.