Sorry I missed the “full size” spare part in the post. Temporary spares definitely spell out that they are for temporary use.
Full size spares are not balanced to my knowledge.
I disagree . . .
All the full size spares I can think of have balancing weights on the rims, as long as they are full-service rims
Benz for one did/does have full size tires on temporary use rims, and I’m not sure those were balanced
Donut spares on the other hand . . . don’t remember ever seeing balancing weighs on those rims
When I worked at a GM (Buick) dealership in the mid 1970s it was the low point of US automobile quality. Due to a tire “shortage” the new Buicks came from the factory with only a spare wheel! My dealership which engaged in many other shady practices actually purchased, mounted, and balanced spare tires for the new vehicles.
Well the trip went well, no noticeable issues due to lack of wheel weights, afraid to look at the year of the tire, but only went over 80 a couple of times. Most of the time was around 70 to 80. New 70mph speed limit Cut the drive down to the point it was not painful!