How to Identify Run-Flat Tires?
4 Answers
You can determine whether a tire is a run-flat by checking the sidewall markings. Below is relevant information about run-flat tires: 1. Other Identification Methods: (1) Check the Vehicle Model: Due to the high cost of run-flat tires, a single run-flat tire is at least 300-500 RMB more expensive than a regular tire of the same model. Therefore, run-flat tires are generally only equipped on mid-to-high-end vehicles. For example, all BMW models come standard with them, while Mercedes-Benz and Audi equip them on a few high-end sedans. (2) Tire Model: Generally, the aspect ratio of run-flat tires is below 55, and it is rare to see one above 60. The English term for run-flat tires is "run on flat." For instance, Goodyear tires are marked with the abbreviation ROF, Pirelli uses R-F, Bridgestone uses RFT. There are also different English markings, such as Michelin's ZP (Zero Pressure), Continental's SSR, and Hankook's HRS. 2. Definition: The technical name for run-flat tires is "Tire Pressure Monitoring System," abbreviated as RSC. The inflated tire's sidewall is the main part that supports the vehicle's weight, especially for tires with a larger aspect ratio (the ratio of tire height to width), where the sidewall is very "thick."
When I was helping out at the auto repair shop, I often encountered this issue. The most straightforward way to identify run-flat tires is to look for the sidewall markings: abbreviations like RSC, RF, or ZP. For example, Michelin uses ZP, while Pirelli marks theirs as RFT. When you touch the sidewall, it feels much stiffer than regular tires because of the reinforced multi-layer structure inside, which can support the vehicle's weight even when deflated. Factory-equipped run-flat tires have wheel rims with raised edges to prevent the tire from coming off the rim. After a blowout, you can actually drive about 80 kilometers, but the vibration is very noticeable, and the steering becomes particularly heavy. Normally, driving with run-flats feels much bumpier than with regular tires, with a pronounced thud over speed bumps, and the road noise is also louder.
Last time I accompanied a friend to pick a used car, I specifically researched this matter. First, check the tire model manual—run-flat tire models usually have special suffixes, such as Bridgestone DRIVEGUARD. On-site, you can press the middle part of the tire sidewall with your fingernail: regular tires will dent easily, while run-flat tires feel as hard as pressing a wooden board. When checking tread depth, pay attention to the thicker shoulder area. If you find special flange grooves in the center of the rim while changing the spare tire, it’s likely equipped with run-flat tires. Another clever trick: after parking, observe the contact area between the tire and the ground—run-flat tires deform much less. If you’re still unsure, take a photo and ask for advice on a professional forum.
Last week, I finally figured out how to identify a run-flat tire after getting a nail puncture. The sidewall of a run-flat tire must be marked with the words "RUN FLAT" or a hump icon, and there is a thickened rubber support ring inside the sidewall. After the onboard computer pressure warning, it will indicate that continued driving is supported. During the 30-kilometer drive back to the repair shop with a punctured tire, there was a buzzing vibration when the speed exceeded 60 km/h, and the steering became noticeably heavier but remained controllable. The maintenance manual specifies that the tire pressure range is about 0.2 bar higher than that of regular tires. Remember to check if there is a special certification code next to the production date.
