While 70 miles is generally accepted as the maximum distance for a compact spare, it is best to consult the car's manual for an exact figure. Additionally, manufacturers recommend that drivers travel no faster than 50 miles per hour with the spare in use.
As car makers lighten vehicles to make them fuel efficient, many have replaced full-sized spare tires with smaller, "donut" versions. These tires often have fewer layers of steel and polyester under the rubber, so they are not as durable as regular tires. Because a donut is smaller than the other wheels, it negatively impacts the car's cornering, handling and braking. Thus, for safety, a full-sized replacement tire should be purchased as soon as possible.