Pothole Damage Check: Inspect Tires After Impact

Why pothole impacts damage tires

A pothole impact is a sudden, concentrated load on a small area of the tire. The tire absorbs the energy of the hit, which can compress the sidewall, bend the rim, and stress the internal structure. Tires are designed to withstand normal road loads, but a hard impact can exceed what the structure can handle, leading to damage that is not always visible from the outside.

The sidewall is the portion of the tire between the tread and the bead, according to the definition in Federal Motor Vehicle Safety Standard No. 139. The bead is made of steel wires wrapped or reinforced by ply cords and shaped to fit the rim. A pothole hit can damage either area, and damage to the internal cords or plies can be hidden by the outer rubber. Understanding these parts helps you know what to look for during an inspection.

Immediate checks after impact

Right after hitting a pothole, pull over when it is safe. First, check the tire pressure. If the tire is losing air quickly, you will notice a change in handling or a low pressure warning from your tire pressure monitoring system. Federal Motor Vehicle Safety Standard No. 138 requires TPMS to illuminate a warning within 20 minutes when pressure drops to 25 percent below the recommended cold inflation pressure. A slow leak may take longer to show up, so check the pressure again after a few hours.

Second, do a quick visual walk-around. Look at all four tires, not just the one that hit the pothole. The impact can damage the opposite tire on the same axle, or the rear tire on the same side. Check for any visible bulges, cuts, or deformities, and look at the wheel for bends or cracks. If you see obvious damage, do not drive on the tire. If the tire is still holding air and looks fine, continue with a more thorough inspection at home.

Sidewall bulges and cuts

The sidewall is the most common place for pothole damage to show. Run your hand slowly over the entire sidewall, from the bead to the tread, on both the inner and outer side of the tire if you can reach. You are feeling for a bulge, which is a soft spot or raised area that indicates the internal cords have broken. A bulge means the sidewall structure is compromised, and the tire should be replaced.

Also look for cuts, gouges, or cracks. Federal Motor Vehicle Safety Standard No. 109 defines cracking as any parting within the tread, sidewall, or innerliner that extends to cord material. If you can see cords or ply material through a cut, the tire is unsafe to drive on. Even a cut that does not reach the cords can weaken the sidewall over time. If you see any cut deeper than a surface scratch, have the tire inspected by a professional. For more on sidewall damage, see Sidewall Crack vs Scratch.

Bead and rim area check

The bead is where the tire meets the rim. A hard pothole hit can unseat the bead or damage the bead area, causing a slow leak that is hard to find. Look closely at the line where the tire rubber meets the metal rim, all the way around the wheel. Check for any gaps, tears, or rubber that looks pushed or folded. If you see damage here, the tire may not seal properly, and air can escape.

You should also check the rim itself. A bent or cracked rim can damage the bead even if the tire looks fine. Federal Motor Vehicle Safety Standard No. 110 requires that the sum of the maximum load ratings of the tires fitted to an axle not be less than the gross axle weight rating, which means the wheel and tire assembly has to handle the vehicle's load. A damaged rim cannot support the tire bead correctly. If you suspect rim damage, have the wheel inspected or replaced before mounting a new tire.

Internal breaks you cannot see

Internal damage, such as broken belts or ply separations, may not be visible from the outside. Federal Motor Vehicle Safety Standard No. 119 lists tread separation, sidewall separation, ply separation, and cord separation as types of damage that a tire must not exhibit. These conditions can develop after an impact, sometimes days later.

Signs of internal damage include vibration at highway speed, a thumping noise, or a tire that slowly loses air. A bulge on the tread surface, rather than the sidewall, can indicate a broken belt. If you notice any of these symptoms after hitting a pothole, have the tire inspected by a professional. Internal damage is not repairable, and the tire will need to be replaced. For more on what happens, see Tire Sidewall Bulge and Wobble After a Pothole.

When to replace the tire

If you find a bulge, a crack that reaches the cords, exposed ply material, or any bead damage, replace the tire. Do not drive on it, even for a short distance. A damaged sidewall can fail suddenly, especially at highway speed. Federal Motor Vehicle Safety Standard No. 139 requires that tires show no visual evidence of tread, sidewall, ply, cord, innerliner, or bead separation, chunking, broken cords, cracking, or open splices. A tire with these conditions does not meet the standard and should not be used.

If the tire only has minor surface damage and holds pressure, you may be able to keep using it, but have it inspected by a professional as soon as possible. A tire shop can check for internal damage that is not visible. When replacement is needed, pick a tire that matches the size and load rating of the other three tires. For guidance on choosing replacement tires, see Tire Replacement Guidelines and the best car and SUV tires.

What to pick for your situation

Questions

How can I tell if my tire is damaged after hitting a pothole?

Check the tire pressure, look for bulges on the sidewall, inspect the bead area where the tire meets the rim, and look for cuts or cracks that expose cords. If the tire is losing air or you notice vibration while driving, have it inspected by a professional.

Is a sidewall bubble after a pothole dangerous?

Yes. A sidewall bulge indicates that the internal cords have broken, which weakens the tire structure. The tire can fail suddenly, especially at highway speed. Replace the tire as soon as possible.

Can a pothole damage the inside of a tire without visible signs?

Yes. Broken belts or ply separations can happen inside the tire without showing on the outside. Symptoms include vibration, thumping sounds, or slow air loss. A professional inspection can detect internal damage.

Will my TPMS warn me about pothole damage?

A tire pressure monitoring system will warn you if the tire is significantly under-inflated. Federal Motor Vehicle Safety Standard No. 138 requires the warning to illuminate within 20 minutes when pressure drops to 25 percent below the recommended level. TPMS will not detect structural damage like a bulge if the tire holds air.

Can a pothole damage the tire bead?

Yes. A hard impact can unseat the bead from the rim or damage the bead area, causing a slow leak. Check the line where the tire meets the rim for gaps, tears, or folded rubber.

How long can I drive on a tire after hitting a pothole?

If you see visible damage, do not drive on the tire. If the tire holds air and looks fine, drive cautiously and have it inspected by a professional as soon as possible. Internal damage can get worse over time.