Run-flat tires are standard on most BMW vehicles in production, as of 2015. Higher-performance BMW cars such as the M3 sedan and other M-series vehicles often do not come standard with run-flat tires due to the lower performance of most run-flat designs as compared to traditional tires.
Run-flat tire designs use stiffer sidewalls than traditional tires, enabling drivers to drive safely for longer distances, even if the tires lose air pressure. The use of run-flats allows BMW and other car manufacturers to remove traditional spare tires from their vehicles to save weight and improve fuel economy. However, the thicker sidewall also reduces the tire's performance in more aggressive driving.