What is a Run-Flat Tire?
3 Answers
Run-flat tires, also known as zero-pressure tires, are marked with RSC on the sidewall. Structurally, run-flat tires are not significantly different from regular tires, except for the reinforced design on the sidewall. This reinforcement allows the tire to continue supporting the vehicle even when it is punctured or suddenly loses pressure, making it a symbol of safety and high-end tires. The main advantage of run-flat tires is safety. Compared to regular tires, run-flat tires have thicker and more robust tread designs, with sidewalls that are highly resistant to deformation. In the event of a puncture or sudden loss of pressure, the vehicle can still travel up to 250 kilometers at a speed of 80 kilometers per hour. The sturdy sidewall ensures that the tire and wheel rim do not deform, preventing any shift in the vehicle's center of gravity and thereby enhancing driving safety.
Run-flat tires are actually called 'run-flat tires'—don't be fooled by the name, they can still blow out! It took me ten years of driving to figure this out. These tires have thickened rubber sidewalls and hidden high-temperature-resistant support structures inside. Even if punctured, they won’t instantly go flat and can last for about 80 km at speeds below 80 km/h. My BMW came with these tires stock—once had a blowout on the highway, the car noticeably leaned to one side, but I could still steer it to the service area. But be warned: these tires are about 30% harder than regular ones, so they’re bumpier over speed bumps and noisier too.
For frequent long-distance drivers, run-flat tires are a lifesaver! These tires have a special structure with extra-thick sidewalls containing honeycomb-like support structures. The principle is simple: when a tire blows out, these rigid supports prevent the rim from directly contacting the road. Last time I ran over a steel bar in the suburbs, the tire pressure warning light came on, but the car remained stable and I could drive to the repair shop. The mechanic said these tires save spare tire space, but they're expensive - one costs as much as two regular tires. Plus, they're harder to repair, and many shops refuse to work on them. In my opinion, they're worth it for highway driving, but may not be cost-effective for city commuting.
