There are two general types of run-flat tires: Self-supporting and self-sealing (via in2tires). The former utilizes a stiffer and reinforced sidewall construction to support the vehicle after losing air pressure. Meanwhile, the latter features a thin layer of sealant that helps maintain air pressure after a puncture, in2tires notes, pointing out that self-sealing run-flat tires still need air to operate correctly, while self-supporting run-flats can keep you going even after losing all air pressure.
The Drive explains that the most common run-flat tire you can buy is the self-supporting tire, although manufacturers like Pirelli and Continental are now offering self-sealing run-flat tires. You can identify a run-flat tire by visually inspecting the sidewall. Depending on the brand, run-flat tires will have RFT (Run-Flat Tire), SSR (Self-Supporting Run-Flat), EMT (Extended Mobility Tire), or ZP (Zero Pressure) markings, according to Toee Tire.
Run-flat tires are not compatible with any vehicle. Only vehicles that came with run-flats from the factory can use run-flat tires. Besides having a standard TPMS, new cars with standard run-flats have particular changes to the suspension and chassis to accommodate those special tires — otherwise, Family Handyman notes, the tires may unexpectedly separate from the wheel bead. If your vehicle originally came with run-flat tires, it is possible to replace them and mount conventional tires instead, as Firestone explains. Remember that OEM run-flat vehicles do not have tire-changing tools and a spare tire in the trunk, so keep this in mind before making the switch.