Equipment Tests > Bull Bars

Plastic bullbars are by no means a new invention, but recent steps forward in technology have allowed for a resurgence in the popularity of the plastic bar. While most models are unsuitable for mounting winches, plastic bars are the favoured option of campaigners for pedestrian safety, as their elastic and deformable nature can lessen the impact of a collision. However, it is this elasticity that has drawn criticism from some circles, who claim that in certain circumstances the bar can deform too far, allowing any obstacle to come into contact with the areas of the car that the bar has been designed to protect, particularly the radiator.

The Airbag Debate
The next option to consider is how the bullbar is mounted to your vehicle. Some bars completely replace the current bumper from the 4WD, while others incorporate the existing bumper into the design. You'll also need to choose between a bar which uses mounting brackets versus a chassis mount system. Newer bullbars may utilise deformable, impact absorbing mounts to assist with airbag deployment in the event of an accident.

In terms of new car warranty and correct operation of all safety devices on your 4WD, there is no thornier issue than that of bullbars and airbag compatibility. A quick explanation of the airbag concept is necessary to fully understand how an incompatible bullbar could have a serious effect on your vehicle, and your safety.

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Current vehicular designs incorporate crumple zones into the chassis, which determines the vehicles 'crash pulse'. The crash pulse is a measure of deceleration, usually taken from the occupants position, when the vehicle hits an obstacle. The front of the vehicle has an almost instant stop, but because the vehicle is designed to crumple, the occupant's rate of deceleration is considerably less. The issue of collision related injury to passengers boils down to the rate of deceleration. The faster an object decelerates, the more load there is on the object and it is this force that can have the most devastating effects on vehicle occupants.

The airbags in a vehicle are designed to deploy at precisely the right moment, timed to the millisecond. Any disruption to the vehicle's crash pulse would have an effect on the timing of deployment of the airbags. With this is mind, it fell to the designers of bullbars, both original equipment and after market, to come up with a system that incorporated the airbag sensors, and didn't disrupt the vehicle's crash pulse. In order for some manufacturers to achieve this goal, it has been necessary to engineer extra crumple zones into the mounting brackets of the bullbars.

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