As the name give the clue that this type of tyres allow you to continue driving after a punture, although the sidewalls are stiff, so the ride can suffer yet it is very useful specially in the case of emergency. Changing a deflated tyres usually takes some time and no one likes to do that in case you are in emergency or hurry so in that case RUN-FLAT tyres proves out to be quite helpful.
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| RUN-FLAT TYRES (INNER LINING) |
Definition :
A run-flat tyre is a pneumatic vehicle tire that is designed to resist the effects of deflation when punctured, and to enable the vehicle to continue to be driven at reduced speeds (up to 55 mph (90 km/h)), and for limited distances of up to 100 mi (160 km), or even 200 mi (320 km) depending on the type of tire.
Performance characteristics :
Depending on the design, some run-flat tires perform better than regular tires, and some slightly worse. Some run-flat tires have a 20% higher rolling resistance, in part due to their added structural material and mass. On the other hand, internal bracing in some run-flat tires reduces deformation, with the opposite effects of reducing rolling resistance and improving fuel efficiency.
Further advantages are derived from not needing to carry a spare wheel: The space can be used for other purposes. Also, the absence of a spare wheel contributes to lower vehicle weight which will in turn reduce fuel consumption, reduce harmful exhaust emissions, improve performance, handling and braking characteristics. However, these may be negated by the increased weight of the tires if they are self-supporting.
Due to reinforcement in tire side walls, run-flat tires usually give firmer rides compared to conventional tires.
The first producer of run-flat tyres is Michelin. It was also produced by Dunlop in 1972. Most recently bridgestone run-flat tyres are provided in BMW cars.The automaker promoted these as a safety feature and as an alternative to carrying a spare tire.
