What size is my spare tire?
The spare tire size is vehicle-specific. Many cars use a compact donut spare that’s smaller than the regular tires, while others carry a full-size spare that matches the wheel size of the other tires. Some newer models rely on run-flat tires or sealant kits instead of a traditional spare. To know your exact spare size, check the tire sidewall, the vehicle’s door-jamb placard, or the owner’s manual.
In this article, we break down the common spare configurations, explain where to find the exact size on your vehicle, and outline what to do if your spare doesn’t seem to fit. This guidance helps you stay safe on the road and plan for a timely tire repair or replacement.
Understanding spare tire configurations
Spare tires come in a few different configurations. Here’s a quick guide to the most common types you might find in your trunk or under your car.
- Donut spare (temporary spare): A small, lighter-weight tire with a reduced speed and distance rating. Typical size markings include things like T125/80R15 or similar; the exact size is printed on the sidewall.
- Full-size spare: A tire and wheel that match the size of your regular tires. It’s designed for longer-term use until you can replace or repair a damaged tire. The size may not always be identical to every tire on the car in every model, but it closely matches the vehicle’s standard wheel/tire size.
- Run-flat or no spare: Some vehicles use run-flat tires that can be driven a limited distance after a puncture, or they may omit a spare entirely in favor of a sealant kit and roadside assistance. In this case there isn’t a separate spare tire size to match.
Understanding these configurations helps you plan for what to do after a puncture and ensures you don’t rely on an incompatible spare in an emergency.
Where to find your exact spare size
To verify the exact spare size for your car, use these steps. They cover the most reliable sources of the information.
- Inspect the spare tire itself for a size stamp on the sidewall (for example, P225/65R17 or T125/80R15). The numbers are the exact size of the spare.
- Check the spare wheel or the storage compartment label. Some cars place a listing or a sticker on the storage tray or underside of the floor panel.
- Look at the door-jamb placard (usually on the driver’s door frame) for recommended tire sizes and any reference to a spare or “Temporary spare.”
- Consult the owner’s manual or the manufacturer’s official website if you cannot find the spare size in the car itself. The manual often lists the spare size or the compatible tire/wheel specifications.
By verifying these sources, you’ll know the exact spare size for your vehicle and avoid fitting issues during an emergency.
What to do if your spare doesn’t fit
If you discover that the spare you have doesn’t fit the vehicle’s tire or wheel requirements, take these steps promptly to stay safe.
- Do not force-fit a wheel or tire that is the wrong size. Driving with an ill-fitting spare can damage the vehicle and create a safety risk.
- Contact roadside assistance or your vehicle’s emergency service. They can arrange a proper tire change or transport to a service facility.
- Seek the correct spare or wheel as soon as possible. If your car uses a full-size spare, ensure it matches the size and speed rating of the other tires; if it uses a donut, replace it with the correct full-size tire when available.
- Visit a tire shop or dealership to obtain the proper spare size and have your regular tires inspected for wear and balance during the replacement.
Having the right spare size on hand and knowing what to do if it doesn’t fit helps ensure you can handle a tire emergency safely and efficiently.
Summary
Spare tire sizes vary by vehicle. Most cars either carry a compact donut spare, a full-size spare, or rely on run-flat tires or a sealant kit with no spare. To confirm your exact spare size, check the sidewall on the spare, the storage area label, the door-jamb placard, and the owner’s manual. If a spare doesn’t fit, seek roadside assistance and replace it with the correct size as soon as possible. Keeping track of the right spare size helps you stay safe on the road and reduces downtime after a flat tire.
