When you install a spare donut tire on your car you're only supposed to drive on the spare tire for at most 50 miles or until you can get to a tire shop to repair your regular tire or replace the regular tire.
Although there was a time when I was so poor and had to use my spare donut tire for around 3,000 miles before I was able to purchase a new tire.
So in that experience 3,000 miles is okay to drive on a spare donut tire but it's not recommended.
Now in my vehicles I just keep a regular sized tire for a spare in my vehicle and can afford to replace the tires when needed.
Spare donut tires are only meant to be temporary and you really should not drive over 50 MPH on a donut tire for safety.
Regular sized spare tires can go as long as the regular tires on your vehicle and you can drive at a higher speed with those tires.