It’s also wise to replace the spare tire after eight years, even if it hasn’t been used. The materials in a spare tire degrade over time, leaving you without a reliable spare. How Long Can I Drive on a Donut Spare Tire? Ideally, you don’t want to drive the donut spare tire more than 50 miles with a donut spare tire, but less is always better.
As for how long they last, that depends entirely on the specifics of the tires. "Economy cars" often have cheaper tires with lower tread wear ratings that don't last as long. Look on the sidewall of the tire, and there should be UTQG markings. It will say something like "Treadwear 360 Traction AA Temperature A."
There is a general range that most car experts agree on: approximately 50 to 70 miles, with 70 as the absolute maximum. It is suggested you keep speeds at or below 50 miles per hour.To figure out the age of your tire, look for a four digit number on the sidewall. This is the time code. The first two digits indicate the week of the year it was manufactured. The last two digits indicate the year. For example, a tire with the time code 1020 was made on the tenth week of 2020. It’s a good idea to replace your spare tire when