The short answer: A clunk or knock over bumps and speed humps is most commonly a worn suspension component — a sway bar link, a control arm bush, or a strut mount — rather than anything more serious. These parts take a constant beating on uneven roads and gradually develop play, which shows up as a knock at exactly the moment a wheel drops into a dip or rides over a bump.
Sway bar links connect your suspension's anti-roll bar to the wheel assembly, and their small ball-joint ends wear over time, developing play that clunks under exactly the kind of vertical movement a speed bump causes. Control arm bushes — rubber isolators that let suspension components move slightly while damping vibration — harden and crack with age, eventually allowing enough movement to knock audibly. Strut mounts, at the top of the suspension where it meets the body, wear similarly and can produce a clunk specifically when turning combined with a bump.
None of these are usually urgent safety issues in the way a brake problem would be, but they do compound: worn suspension components change how your wheel contacts the road, which accelerates uneven tyre wear and gradually affects handling precision, particularly under braking or in an emergency swerve.
How it's actually diagnosed: Suspension noise is genuinely difficult to pin down by sound alone — a mechanic needs the car on a hoist to physically check each component under load, wiggling and pressing on links, bushes and mounts to isolate exactly which one has developed play.
If you've noticed a clunk that's gotten more frequent or louder over recent weeks, get it checked before it starts affecting your tyre wear or handling — most suspension component replacements are a modest, one-off cost if caught reasonably early.
Hearing a Clunk Over Bumps?
We'll put it on the hoist and find exactly which component has worn.