Symptoms
- Tire is completely flat
- Car pulls hard to one side
- Thumping or flapping sound before it went flat
- Warning light or chime
Likely causes
- CommonPuncture from a nail or road debrisOften the tire holds air for a short time before going flat suddenly.
- CommonSidewall blowoutA tear in the sidewall causes air to escape almost instantly, often with a loud bang.
- PossibleValve stem failureA cracked or torn valve stem lets air out fast.
- Less commonWheel came loose from the beadHitting a curb or pothole hard can pop the tire off the rim.
What to do
- Turn on hazard lights and pull well off the road onto a flat, stable surface.
- Stay in the car if traffic is close, or stand well away from traffic if you get out.
- Confirm which tire is flat by walking around the car (with hazards on and care for traffic).
- Check the owner's manual for the jack and spare location, and loosen the lug nuts slightly before jacking the car up.
- Jack the car up, remove the flat, and mount the spare or a fitted replacement.
- Tighten lug nuts in a star pattern once the car is back on the ground.
- Check that the spare is properly inflated and drive at reduced speed to a tire shop.
- Have the flat tire inspected to see if it can be repaired or needs replacing.
Tools and parts
- Spare tire and jack
- Lug wrench
- Wheel wedges or bricks
- Flashlight if at night
- Reflective triangles or flares
Full-size or compact spare tireSearch: “replacement spare tire for [your car model]”
Tire repair kitSearch: “tire plug patch kit”
When to call a pro
If you're on a highway shoulder, near a blind curve, or not comfortable changing a tire yourself, call roadside assistance instead of doing it on the roadside.
Safety
Use caution
Only change a tire on level, stable ground away from moving traffic; never crawl under a car supported only by a jack.