Tire Flat Spots: Causes and How They Smooth Out

What Is a Tire Flat Spot?

A flat spot is a flattened area on the tread circumference of a tire. It appears as a slightly worn or smooth patch where the tire has been pressed against the ground while stationary. The rubber in that area temporarily or permanently loses its round shape.

Tires are flexible structures designed to deform under load and recover when the load is removed. According to federal safety standards, a pneumatic tire is a mechanical device made of rubber, chemicals, fabric and steel, and it contains air that sustains the load. When the vehicle is parked, the weight of the vehicle rests on a small patch of the tire, and the rubber compounds in that patch can take a set if the tire remains motionless for hours or days. This is the origin of a flat spot.

Temporary and Permanent Flat Spots

Temporary flat spots are common and usually not a cause for concern. They occur most often in cooler weather or after a vehicle has been parked overnight. The tire's rubber is flexible at normal operating temperatures, but when cold, it may stiffen and retain a flattened shape. Once the tire rolls for a few miles, friction warms the rubber, and the flat spot disappears.

Permanent flat spots, on the other hand, do not go away with driving. They can develop when a vehicle is parked for weeks or months, especially if the tires are under-inflated or the vehicle is heavily loaded. In some cases, the tire's internal structure can be damaged, leading to a permanent deformation. If a flat spot does not smooth out after a reasonable drive, the tire may need to be replaced.

Why Flat Spots Form After Parking

When a vehicle sits, the full weight of the vehicle presses down on the small contact patch of each tire. The rubber and the internal belts, which are designed to flex while rolling, are held in a fixed position. Over time, the compound can remember that shape, particularly in cooler temperatures when rubber is less pliable.

Tire pressure plays a role. Properly inflated tires maintain their shape better than under-inflated ones. Federal regulations require vehicles to be equipped with tire pressure monitoring systems that warn when pressure drops significantly, which can help you avoid parking with a soft tire. Keeping tires at the vehicle manufacturer's recommended cold inflation pressure is one of the best defenses against flat spotting.

Temporary Flat Spots Smooth Out with Driving

Most temporary flat spots disappear within a few minutes of driving. As the tire rotates, flexing generates heat, and the rubber returns to its original shape. You may notice a slight thumping or vibration at first, but it should taper off as the tire warms up.

If you experience a vibration that does not go away after driving for several miles, check your tire pressure and look for other signs of damage. A persistent flat spot could indicate a more serious issue. In that case, have a professional inspect the tire. For more on diagnosing vibrations, see our guide on vibration at speed.

Permanent Flat Spots: When They Don't Go Away

Permanent flat spots can happen when a tire is left underinflated for a long period, or when a vehicle is stored on a hard surface without moving for several months. The tire's internal structure, including the belts and casing, can become permanently distorted.

A permanent flat spot will cause a continuous vibration and a thumping noise at speed. It can also lead to uneven wear. Federal standards for tire selection require that the load on each tire not exceed its rated capacity, but even a properly loaded tire can flat-spot if left motionless too long. If the flat spot does not smooth out after a thorough road test, the tire should be replaced. Driving on a permanently flat-spotted tire can worsen the damage and affect handling. Review our tire replacement guidelines for more.

How to Prevent Flat Spots

The best way to prevent flat spots is to avoid leaving your vehicle parked for long periods. If you must store a vehicle for more than a few weeks, consider raising it on jack stands to remove weight from the tires, or move the vehicle periodically to change the contact patch.

Maintaining proper tire pressure is also important. According to the U.S. Tire Manufacturers Association, today's tires are engineered for safety and performance, but they still rely on correct inflation. A TPMS can alert you to low pressure, but it only helps after the fact. Check your pressure monthly, especially before long-term storage.

If you are storing tires separately, store them in a cool, dry place away from sunlight and ozone sources. Stack them or stand them upright, but avoid leaving them on a concrete floor for extended periods. For more storage advice, see our tire storage guide.

What to Do If You Have a Flat Spot

If you suspect a flat spot, first check the tire pressure and adjust it to the recommended level. Then take the vehicle for a drive of at least a few miles, including some highway speeds, to allow the tires to warm and flex.

If the vibration remains, have a qualified technician inspect the tires. They can measure tread depth, look for bulges or separations, and determine if the tire is safe to use. Sometimes a flat spot can be masked by a balance issue, so a professional diagnosis is valuable. Learn more about tire balancing and whether it can help.

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Questions

How long does it take for a temporary flat spot to smooth out?

Most temporary flat spots disappear within the first few minutes of driving. As the tire warms up and flexes, the rubber regains its shape. A light thumping sensation may persist for a few miles but should fade quickly.

Can a flat spot cause a vibration at highway speeds?

Yes. A flat spot creates an imbalance in the tire's roundness, which can produce a noticeable vibration or thumping, especially at higher speeds. If the vibration fades after a few miles, it was likely a temporary flat spot.

Will underinflated tires make flat spots more likely?

Underinflated tires have a larger and more flexible contact patch, so they are more prone to flat spotting when parked. Keeping tires at the vehicle manufacturer's recommended pressure reduces the risk.

Should I replace a tire with a permanent flat spot?

If a flat spot does not smooth out after a thorough drive, the tire has likely suffered permanent structural distortion. Continuing to drive on it can cause vibration, uneven wear, and potential handling issues, so replacement is usually the safest choice.

Can new tires develop flat spots?

Yes, any tire can develop a temporary flat spot if the vehicle sits for several days, especially in cold weather. New tires are not immune because the rubber compounds still respond to prolonged pressure and temperature.

Does storing a car on a hard surface increase the chance of flat spots?

The surface type matters less than the duration of storage and tire pressure. Even on a flat concrete floor, a tire under load will deform over time. Raising the vehicle on jack stands or moving it periodically helps prevent flat spots.