A spare tire will not fit in the 25 inch wide frunk.Just saw this thread about the Frunk and making an alternative for storing the spare tire— love the idea!! My Honda Ridgeline keeps the spare in a compartment below the bed floor just like the Rivian. And while driving through the North Maine Woods, I blew a tire and needed the spare. Had to empty all the gear to access the tire. It was a pain, but at least it was a sunny day— could have been worse!