Exhaust or a related part
A loose exhaust component is one possibility mentioned in motoring guidance. A rattle may seem to come from somewhere else, so do not reach underneath the car or try to secure a hot part yourself.
Car noise guide
Why is my car knocking or rattling over bumps?
A knock or rattle over a pothole, speed bump or uneven road is a clue, not a diagnosis. The AA lists a loose exhaust part and a suspension issue among possible causes. The sound alone cannot show which part, if any, needs repair.
Describe a car symptomPossible explanations
What might knock or rattle over a bump?
Several parts can make similar sounds, and noise can travel through the vehicle. An inspection is needed to identify the source.
Suspension
Suspension components are another possible source of a knock over uneven roads. The sound cannot show which component is involved or whether it is safe to continue driving.
Other loose or worn parts
Other parts can sound similar. Note what you already observed and let a garage inspect the vehicle rather than replacing parts based on a sound description.
When should I stop driving?
If the car pulls, feels unstable, steering or braking changes, a tyre appears to touch the body, or you are unsure it is safe, stop somewhere safe and contact a breakdown provider or garage for advice. Do not crawl under the vehicle or touch hot or moving parts. If the noise is persistent but the vehicle feels normal, arrange a garage inspection and describe what you heard.
Common questions
Knocking and rattling over bumps
Does a rattle over bumps mean my suspension is broken?
Not necessarily. Suspension is one possible source, but an exhaust part or another component can make a similar noise. A garage inspection is needed to identify the cause.
Can I keep driving with a knocking noise?
The sound alone cannot establish whether the vehicle is safe. Stop and seek help if handling, steering or braking has changed, or if you are unsure. Arrange an inspection for a persistent noise.
What should I tell the mechanic?
Give the vehicle details and describe the road surface, speed and any changes in steering, braking or handling. Separate what you observed from what you think caused it.
Should I record the noise?
Only if you can do so safely while stationary or with a passenger recording. Never handle a phone while driving or recreate a situation that may affect vehicle control.
Further reading
Motoring guidance on unusual car noises
These sources describe general possibilities; they do not identify the cause on an individual vehicle.
More on car sounds
Read the car noise guide →Compare other common noises
Use the car noise guide for sounds while braking, turning, accelerating or after switch-off.