We’ve all experienced a flat tire at one point or another. After a bit of sweating and wrestling with the jack on the shoulder of the road, you finally open up the trunk floor to pull out your savior: the spare tire. But here is where the story takes a dark turn for a lot of drivers. You pull that donut out, and instead of a firm, bouncy tire, it’s as limp and flat as a pancake.
It is heartbreaking to see someone get stranded not because they had a flat, but because their backup plan failed. Your spare tire is a "set it and forget it" part of your car, but it shouldn't be. Today, we’re talking about why that little tire in your trunk needs a little love and how to make sure it’s actually inflated and ready to use.
Why Spare Tires Lose Air (Even When They Aren’t Used)
It seems unfair, doesn't it? A tire that has never touched the pavement should be perfect. However, tires are naturally porous. Over months and years, air molecules slowly seep through the rubber. This process is even faster for spare tires because they are subjected to extreme temperature swings.
Think about it: your spare lives in a trunk that can reach extremely hot temperatures in the summer and drop to sub-zero temperatures in the winter. This constant expansion and contraction of the air inside causes the pressure to drop. Most spares require significantly higher pressure than your standard tires, usually around 60 PSI. If yours has been sitting back there for three years without a check-up, it’s likely sitting at 20 or 30 PSI, which is nowhere near enough to support the weight of your vehicle.
The Anatomy of a Reliable Spare
Not all spares are the same, and knowing what you have is half the battle. When you check your trunk this afternoon (and we really hope you do!), keep these three things in mind:
- The 60 PSI Rule: As mentioned, most temporary spares need a lot of air. Always check the sidewall of the tire for the recommended pressure. It will be much higher than your four main tires.
- The Age Factor: Rubber degrades over time, even if it has plenty of tread. If your car is more than 8 or 10 years old and still has the original spare, the rubber may be "dry rotted." If you see tiny cracks in the sidewall, that tire is a safety risk.
- The Five-Mile Rule: A donut is designed to get you to a repair shop, not to take you on a road trip. They are typically rated for a maximum speed of 50 mph and a distance of about 50 miles.
Our Pro-Tips for Spare Tire Maintenance
You don't need to be a mechanic to ensure your backup plan is solid. Here is how we recommend staying ahead of a roadside disaster:
- Check the Pressure Monthly: Every time you check the air in your regular tires, pop the trunk and check the spare. It takes thirty seconds but could save you hours of waiting for a tow truck.
- Inspect the Tools: A full spare is useless if your jack is rusted shut or your lug wrench is missing. Every once in a while, make sure the kit is complete and functional.
- Flip It Over: Most spares are stored face-down. This makes the valve stem hard to reach. If possible, store it face-up so you can check the pressure without having to lift the tire out of the well.
- The "Glow Up" Test: If you’re checking your spare at night, ensure you have a working flashlight in the kit. Batteries die, too!
What If Your Car Doesn't Have a Spare
Many modern vehicles, specially newer sedans and EVs, don't even come with a donut tire anymore. Instead, they come with a "fix-a-flat" kit or an air compressor with sealant. If that’s you, it is even more important to check that kit. Those sealants have expiration dates, and if the canister is five years old, it might not work when you need it.
If your car didn't come with a spare and the idea of being stranded with just a can of goo makes you nervous, give us a call. We can often help you source a spare kit that fits your vehicle, giving you that extra layer of security.
We’ve Got Your Back (And Your Tires)
Next time you’re in for an oil change or a brake check, don't be afraid to ask, "Hey, can you guys check the air in my spare?" We can do it as a standard part of our inspections. Check it today, or better yet, bring it by Severson Auto Service in Rochester, MN.
We’ll make sure your "donut" is puffed up and your main tires are in top shape so you can drive with total peace of mind!
