The concept
The parking brake is primarily intended to prevent the vehicle from rolling while parked; it brakes the rear wheels.

See also:
Remove unnecessary cargo
Additional weight increases fuel consumption. ...
Tire inflation pressures for X6 xDrive50i
...
Starting Roadside Assistance without
BMW Assist or TeleService
1. "BMW Assist" or "ConnectedDrive"
2. "Roadside Assistance"
The Roadside Assistance number is displayed.
If the mobile phone is paired, a connection is established ...
