July 28, 2023

What are Run-Flat Tyres and How Do They Work?

What are Run-Flat Tyres?

Run-flat tyres are specialized tyres designed to remain functional even after sustaining a puncture. Run-flats are equipped with reinforced sidewalls and cutting-edge materials that can temporarily support the weight of the vehicle, allowing the driver to continue driving for a limited distance at reduced speeds.

How Do Run-Flat Tyres Work?

The defining feature of run-flat tyres is their ability to maintain their structural integrity despite low or zero air pressure. It's achieved using strong and stiff sidewalls, often crafted with reinforced rubber or high-strength materials.

In an unfortunate event of a tyre blow-out, run-flat tyres mitigate major risks by providing temporary support, enabling the driver to reach a nearby service station or safe location without the immediate need to change the tyre.


Run-Flat Tyres vs Conventional Tyres:

1.     Puncture Resistance:

Run-flats boast enhanced puncture resistance due to their reinforced sidewalls. They can continue to function with a loss of air pressure caused by punctures of certain sizes, reducing the risk of accidents during emergencies.

Conventional tyres lack reinforced sidewalls, making them susceptible to complete air loss after a puncture. This necessitates an immediate stop and tyre change or assistance from professionals.

2.     Driving After Puncture:

Run-flat tyres allow drivers to continue driving for a limited distance (typically around 50 miles) at reduced speeds (up to 50 mph) following a puncture. This feature ensures convenience and safety when immediate stopping may not be possible or safe.

After a puncture, normal tyres offer no support, requiring drivers to halt and change the tyre or seek professional aid.

3.     Tyre Pressure Monitoring System (TPMS):

Many vehicles equipped with run-flat tyres also incorporate a TPMS. This system constantly monitors tyre pressure, alerting the driver when significant air pressure loss occurs. This early warning enables drivers to take prompt action and avoid further tyre damage.

While some modern vehicles are equipped with TPMS, it is not very common. In vehicles equipped with conventional tyres, drivers may not be immediately aware of a puncture until they experience handling issues.

4.     Ride Comfort:

The stiff sidewalls of run-flat tyres may lead to a slightly firmer ride compared to normal tyres. That said, continuous advancements in tyre technology have resulted in improved ride comfort in newer run-flat models.

Conventional tyres generally offer a more comfortable ride due to their flexible sidewalls, which aid in absorbing bumps and road vibrations.


Can you repair a Run-Flat Tyre?

It is essential to remember that run-flat tyres are designed for temporary use and should be replaced as soon as possible after a puncture or damage.

Remember, running flat tyres on your car doesn't just pose risk to you, but also to others on road, and they need to be fixed as soon as you notice you're running flat tyres.


How long do run-flat tyres last?

Run-flat tyres are typically built from the same materials as normal tyres, so they should last as long as standard tyres. However, the legal minimum tread depth of 1.6mm still applies.


How to identify run-flat tyres in the UK?

In the UK, run-flat tyres are commonly identified with a symbol on the sidewall. Each brand has its own naming and identification means. Look for the specific symbol for the brand of tyres you have. 

Some may have the letters "RF" or "RUN FLAT" printed on the sidewall. It is essential to remember that not all tyres with reinforced sidewalls are run-flat tyres, so ensure to check for these specific markings to confirm whether your tyres are run-flat or simply reach out to the tyre manufacturer or seller.

Finally, whether you opt for conventional tyres or run-flats, regular maintenance and proper care are crucial to ensure safety, optimal performance and longevity. 

For any tyre-related queries, reach out to our folks at Tire Streets. Sign up for our mailing list and get 10% off your first order.