"G" Sensor

The "G" sensor is used to trigger the roll bars if the vehicle should become airborne. the "G" sensor consists of a reed contact, magnet and spring assembly. As long as the vehicle is in contact with the road surface, the spring does not have enough tension to overcome the weight of the magnet and gravity.

Fig 1: Locating "G" Sensor Components (Front)

Courtesy of BMW OF NORTH AMERICA, INC.

However, if the vehicle becomes airborne and weightlessness occurs, the spring will force the magnet up and the reed contact will open. This will signal the electronics of the sensor to trigger the solenoids and the roll bar will deploy.

A time period of approximately .3 seconds with a "G" force of approximately 0.9 or less is required before the bars will deploy.

Fig 2: Locating "G" Sensor Components (Rear)

Courtesy of BMW OF NORTH AMERICA, INC.