(ABC 6 News) — A flat tire is always a bummer, but having a spare tire can help get you back on the road quickly – if you have a spare tire. If you do have one, it might not be ready or safe to use when needed.

Consumer Reports reveals what you need to know before a tire emergency strikes.

“In the event that you do get a flat tire, you should pull off the road as far as you can in a safe area,” said Ryan Pszczolkowski, Consumer Reports Auto Expert.

Next, you’ll want a space-saver spare tire — lovingly called the ‘donut.’ It long ago replaced the full-sized spare in most passenger cars. With any luck, you might go years without needing to use one, but it should not be forgotten.

“Your spare tire expires just like your other four tires,” cautioned Pszczolkowski.

The last two digits of the DOT number on the sidewall of the donut tire indicate the year the tire was manufactured. If it’s older than 10 years, replace it.

A spare tire only works if it’s properly inflated. Check your spare tire’s pressure and condition anytime you check the pressure on your other tires and top off as needed.

60 percent of new cars don’t have a spare tire.

“In an effort from the manufacturers to lower production costs and reduce weight for fuel economy, they’re just leaving the spare tire out. So don’t ever assume you just have a spare tire,” said Pszczolkowski.

Instead, you’ll likely get an air compressor or a can of tire sealant that is supposed to patch a damaged tire and get you to a shop where it can be repaired or replaced.

Some cars, mostly luxury models, come with run-flat tires that allow you to continue driving for a set distance, usually 50 miles at modest speeds—enough to get you home or to a service center for a replacement.

“You shouldn’t be driving around on these tires or a patch tire because that’s not a permanent fix,” concluded Pszczolkowski.

Another important tip from CR – no matter what flat tire solution your car has, learn how to use it before you need it, because you may need to use it in the rain, in the dark, or in other challenging circumstances.