Serious rubber is just part of the 2006 BMW M5’s handling equation. Up front, the M5 gets 19 x 8.5-inch M double-spoke design wheels wrapped with 255/40ZR-19 specially developed high performance tires. Taking up the rear are 19 x 9.5-inch rims shod with 285/35ZR-19s. The 2006 BMW M5 is not equipped with a spare due to the space requirements the four mufflers consume, but the tires are not a run-flat design as you might expect. According to BMW, no run-flats have been developed that meet BMW M Series parameters of speed and weight. In the event of a flat, owners must rely on either the M Mobility system (basically a can of fix-a-flat) or the more likely alternative, roadside assistance.