A guide to run flat tyres – do you need them?

Fitting run flat tyres to your car could improve the road safety of your vehicle. Read our in-depth guide to run flat tyres to see if they are suitable for your car and daily travel. 

Run flat self-supporting tyres are designed to allow a vehicle to continue driving safely for a limited distance even after it has experienced a puncture or a loss of air pressure.

Unlike conventional tyres, which typically deflate rapidly when punctured, run-flat tyres have reinforced sidewalls and special construction that allows them to support the weight of the vehicle even when they are flat or significantly underinflated.

Run flat tyres can provide a number of safety advantages over standard tyres. The benefits of run flat tyres are listed below:

• Run flat tyre have reinforced sidewalls that can temporarily bear the weight of the vehicle, while auxiliary-supported run-flat tyres use a support ring or other structure inside the tyre to provide additional support. This can be particularly useful in situations where stopping on the side of the road to change the wheel may be dangerous in the event of a puncture, such as on busy motorway or in difficult weather conditions.
• You will not risk losing control of the vehicle in the event of a sudden puncture or blowout. 
• Reduced chance of the tyre coming loose or spinning off the wheel rim in the event of a puncture.
• Run flat tyres are perfect for cars that cannot accomodate a spare wheel. According to RAC research, just 3% of new cars are sold with a spare. 

Is your car compatible with run flat tyres? Find out by speaking to someone in the RAC Approved Garages network. 

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It's important to note that run flat tyres have limitations and should not be driven on indefinitely, or at high speeds when deflated. The distance and speed limitations vary depending on the tyre manufacturer and the model of car. It's advisable to consult the vehicle's manual or contact the tyre manufacturer for specific guidelines and recommendations regarding run flat tyres.

Here are some challenges and downsides associated with run flat tyres:

• Tyre Pressure Monitoring System (TPMS): In order to use run flat tyres, your vehicle  must have a working TPMS system. This will be checked at your annual MOT.
• Ride comfort: Run flat tyres typically have stiffer sidewalls and reinforced construction to support the weight of the vehicle when flat. This can result in a harsher and less comfortable ride compared to conventional tyres. The reduced flexibility of the sidewalls can transmit more vibrations and road imperfections to the vehicle's cabin.
• Limited driving distance: While run flat tyres allow you to continue driving for a limited distance after a puncture or loss of air pressure, the distance you can travel is generally restricted. Most manufacturers recommend not exceeding speeds of 50mph (80kmh) and driving distances of 50 miles (80 kms) after a puncture. This limited range can be inconvenient, especially if you're far from home or a trusted local garage.
• Reduced performance: Run flats may not provide the same level of performance as conventional tyres. The stiffer construction and sidewalls can affect handling and cornering capabilities, resulting in slightly compromised performance in terms of traction, braking, and overall vehicle dynamics.
• Higher cost: Run flat tyres are typically more expensive to buy than conventional tyres. Therefore, if a run flat tyre becomes damaged beyond repair, it may require complete replacement rather than a simple repair, adding to the overall cost.
• Limited availability: Run flat tyres are not as widely available as conventional tyres. They are more commonly found in specific sizes and for certain vehicle models. This limited availability may restrict your options when it comes to choosing a replacement tyre or finding a suitable option in case of an emergency.
• Tyre repair limitations: In many cases, run flat tyres cannot be repaired if they are damaged. The reinforced sidewalls and internal structure make it difficult to patch or plug a puncture.

It's important to consider these challenges and weigh them against the benefits before deciding to use run-flat tyres on your vehicle.

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In most cases, the answers is no. Run flat tyres use a reinforced sidewalls and specialised construction which makes it extremely difficult to perform a successful and safe repair. It is recommended to replace a run flat tyre rather than attempting a repair. 

The guidelines for repairing run flat tyres may vary among manufacturers, so it's essential to consult the tyre manufacturer's recommendations and guidelines for your specific tyre model. Some common factors that influence the repairability of a run flat tyre include:

• Type and size of the damage: Minor punctures caused by nails or small objects in the tread area of the tyre may be repairable. However, damages like sidewall cuts, bulges, or significant tread damage may make the tyre ineligible for repair.
• Age and wear of the tyre: The condition and age of the tyre also play a role in determining if it can be repaired. If the tyre is worn close to the legal minimum tread depth or nearing the end of its usable life, it is less likely to be repairable.
• Previous repairs: If a run flat tyre has already been repaired previously, it may not be repairable again due to the potential compromise in its structural integrity.

It's important to note that even if a run flat tyre is repairable, not all garages have the necessary equipment or expertise to perform the repair. Run flat tyre repairs typically require specialised techniques and materials to ensure tyre safety and performance.

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The maximum driving distance on a run flat tyre is 50 miles at speeds not exceeding 50mph. However, this is only a general estimate, it's crucial to consult the specific guidelines provided by the tyre manufacturer and your vehicle's manual for an exacxt distance.

The distance you can drive on run flat tyres after experiencing a puncture or loss of air pressure can vary depending on several factors, including the tyre manufacturer, tyre model, vehicle weight. driving conditions, and driving speed.

To identify a run flat tyre, you can look for certain markings or labels on the tyre sidewall. Here are a few indicators that can help you identify a run-flat tyre:

• Tyre markings: Many run flat tyres have specific markings on the sidewall that indicate their run-flat capabilities. Look for terms like Run-Flat, SSR (Self-Supporting Run-flat), RFT (Run-Flat Technology), ROF, or similar abbreviations. These markings may vary depending on the tyre manufacturer.
• Manufacturer designation: Some tyre manufacturers have their own designations or branding for run-flat tyres. For example, Bridgestone uses the term "DriveGuard" to identify its line of run-flat tyres.
• ISO symbol: The International Organization for Standardization (ISO) has established a symbol to indicate run-flat tyres. It consists of a circle containing the letters RSC (Run-Flat System Component) and can be found on the sidewall of the tyre.
• Owner's manual or vehicle specifications: If you are unsure about whether your vehicle is equipped with run-flat tyres, you can refer to the owner's manual or check the vehicle's specifications provided by the manufacturer. This information should indicate whether run-flat tyres are installed as original equipment on your vehicle.

It's important to note that not all vehicles come equipped with run-flat tyres as standard. Some vehicles may offer run-flat tyres as an optional feature or may require specific modifications to accommodate run-flat tyres.

If you are uncertain about the tyre type on your vehicle, consulting your trusted local garage or contacting the vehicle manufacturer can provide accurate information. Buying run flat tyres can be confusing, so ask your mechanic for any help needed.

It is not recommend to mix run flats with regular tyres. Although there are no laws or legislation against mixing run flats with standard tyres on a car, doing so can have a negative impact on the handling of the vehicle. The strengthened sidewalls of the run flat tyres may affect the steering, braking and grip of the vehicle when mixed with tyres that feature a softer compound and sidewalls. If you are thinking of fitting run flats to your car, it's recommended that you change all four tyres.