Tyre Sidewall Damage: Causes, Is It Safe, and What to Do
The sidewall is the flexible outer wall of the tyre between the tread and the wheel rim. Because it flexes constantly and carries the weight of the car, any damage here is far more serious than a simple tread puncture. Here is what causes sidewall damage, whether you can keep driving, and what you need to do.
Common types of sidewall damage
- Bulges or bubbles: a lump sticking out of the sidewall, usually caused by internal damage after hitting a pothole or kerb. This is a serious blowout risk.
- Cuts and gouges: sharp objects or kerbing can slice into the sidewall and expose or cut the internal cords.
- Cracks and perishing: fine cracks in the rubber from age, UV exposure, or under-inflation.
- Kerbing scuffs: cosmetic scrapes from brushing a kerb, which are usually only surface deep.
- Nails or screws in the sidewall: unlike the tread, these cannot be repaired.
What causes a sidewall bulge?
A bulge almost always follows a sudden impact, such as hitting a pothole at speed or striking a kerb. The impact damages the internal fabric cords of the tyre, and air pressure then pushes the weakened area outward, creating the bulge. The outside may look intact, but the tyre is structurally compromised and can fail without warning.
Is it safe to drive with sidewall damage?
A bulge, a cut that reaches the cords, or a deep gouge is not safe to drive on. These weaken the tyre structure and can cause a sudden blowout at speed, which is extremely dangerous. If you find a bulge or cut, avoid driving on it and arrange a replacement as soon as possible.
Light cosmetic kerbing scuffs that do not reach the cords are usually fine, but if you are unsure, have the tyre inspected. Perished, cracked rubber on an older tyre should also be replaced.
Can sidewall damage be repaired?
No. Under the UK standard for tyre repairs (BS AU 159), only punctures in the central tread area can be repaired. Sidewall and shoulder damage is specifically excluded because those areas flex too much for any repair to hold safely. A tyre with a damaged sidewall must be replaced, not patched.
What to do if you spot sidewall damage
Stop driving on the tyre if the damage is a bulge, cut, or deep gouge. A mobile tyre fitter can come to your home, work, or the roadside, confirm whether the tyre is safe, and supply and fit a replacement on the spot. If the damage came from a pothole, it is also worth having your wheel and alignment checked, as impacts can bend a wheel or knock the tracking out.
Related services & guides
Need a Tyre Fitted Today?
We come to you 24/7, at home, work, or roadside. Average response 30-45 minutes.
