See also:

Bead
The tire bead ensures that the tire sits securely on the wheel. There are several steel wires in the bead to prevent the tire from coming loose from the wheel rim. ...

4MATIC (permanent four-wheel drive)
4MATIC ensures that all four wheels are permanently driven. Together with ESP® and ETS, it improves the traction of your vehicle whenever a drive wheel spins due to insufficient grip. WARNIN ...

Recovering a vehicle that has becomestuck
Pull away smoothly, slowly, and in a straight line when pulling out a vehicle that has become stuck. Excessive tractive power could damage the vehicles. If the drive wheels have become stuck i ...