Symptoms
- Thump-thump-thump that speeds up as the car goes faster
- Noise felt in the seat or steering wheel too
- Noise present even on smooth pavement
Likely causes
- CommonFlat spot on the tire from hard braking or parking in one spot too longA flat spot creates one thump per wheel revolution.
- CommonObject stuck between dual tread blocks or a rock lodged in the treadSmall debris caught in the tread can cause a rhythmic thump.
- PossibleInternal tire separationA belt starting to separate inside the tire causes a rhythmic thump that a tire shop can detect on a spin balancer.
What to do
- Inspect the tread for embedded rocks or debris and remove anything found.
- Look at the tire for an obvious flat spot, especially if the car sat parked for a long time recently.
- If a flat spot is minor and from cold weather sitting, driving a short distance sometimes lets it round back out; if severe, it's permanent.
- Have the tire spun on a balancing machine at a shop to check for internal separation if no external cause is found.
- Replace the tire if internal separation or a permanent flat spot is confirmed.
Tools and parts
Replacement tire if damagedSearch: “tire size for [your car model]”
When to call a pro
If you can't find an obvious cause like debris, have a tire shop check the tire on a spin balancer for internal damage.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.