Radial spare a replacement spare tire for 2013 Gen3?

Pretty much anything will work as long as the bolt pattern matches up... But if you want to take good car of your car and you get a flat front tire... Put the spare on the rear and the full size rear tire up front. This is better for the transmission because both wheels will be the same diameter and rotate at similar speed. And while driving a short distance with a donut tire up front is probably fine to do temporarily, avoiding different wheel size or even different tread depth up front is worth the effort.

 

And follow the rated psi and speed restrictions.
Get a good tire back on asap

 

The OD of the stock spare is pretty much identical.

 

I'm curious about that... Will take a tape measure to the donut next time I pull it out... Seems so much smaller, but from an engineering and design perspective that would make the most sense.

 

They pretty much have to make it close enough to avoid wheel-speed-difference errors from the skid ECU (at least up to the maximum speeds intended for the donut spare).

 

If you are really worried about compatibility, get a full size spare with tires identical with your current tires. In an emergency, nothing beats a full size spare. For me, it worth the loss of space.

 

My old Subaru had enough room for a full size spare tire in place of the donut... Doesn't work so well with a Prius... But way better than a plug-in prius that doesn't even have donut.

 

If you check the spec's, say on TireRack, you'll see they're VERY close. See-is-believing: stack the temp atop the stock, on a flat slab, align on the faces on one side with a carpenter's square, then go round the other side and repeat. The temp is maybe 1/8" shy of stock dia, on our 3rd gen, doing that.