How to Distinguish Run-Flat Tires?
3 Answers
Methods to distinguish run-flat tires: 1. Place the tire flat and stand on it—the sidewall of a run-flat tire is hard; 2. Look for special markings after the tire specifications on the sidewall, such as RF, SSR, ZP, RFT, ROF, or DSST. Run-flat tires, technically known as pressure-retaining tires, consist of an outer tire, a standard inner tube, a spare inner tube, a steel rim, a gas generator or air chamber, a pressure sensor, and a control unit. Differences between run-flat tires and regular tires: 1. Appearance: Run-flat tires have special markings, while regular tires do not; 2. Structure: Run-flat tires have thicker sidewalls compared to regular tires; 3. Performance: Run-flat tires allow the vehicle to continue driving for a period even at zero pressure, a feature regular tires lack; 4. Weight: Run-flat tires are heavier than regular tires; 5. Comfort: Run-flat tires offer less comfort compared to regular tires.
How to identify run-flat tires? Personally, I think the key is to check the sidewall thickness. Regular tires have thinner sidewalls, while run-flat tires have much thicker and sturdier sidewalls – they feel harder to the touch and produce a duller sound when tapped. Another clear indicator is markings like RFT, ZP, or EMT on the sidewall; BMW models often feature the ZP label. After a puncture, these tires can support the vehicle for about 50-80 km, offering superior safety, but they must be installed with a tire pressure monitoring system. Regular tires don’t have this capability. During maintenance, mechanics often point out these features to avoid mistaking them for regular tires when purchasing. They are more expensive but worth the investment.
To identify run-flat tires, I usually check the sidewall markings. For example, look for the letters RFT printed on the side, or brand-specific names like Goodyear's RunOnFlat or Mercedes' EMT. These indicate the tire can continue driving after a puncture. Standard tires only have the size and brand name printed. Additionally, the driving feel differs—run-flat tires provide more stable wheel speed changes. When replacing tires, ensure the rims are compatible to avoid installation errors. Beginners should refer to the vehicle manual or confirm details with a 4S store. This knowledge is practical and useful in daily life, learned after driving school.
