Bull bars – Part: 2 Airbag compatibility

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Categories: Media, Product Information

We have all heard of Airbag compatibility for bull bars. Surprisingly, many 4wd enthusiasts are not aware of the implications that the fitting of an aftermarket replacement bull bar has on the airbag system.

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Airbags are considered part of a vehicle’s Supplementary Restraint System (SRS) and are designed to assist in restraining and protecting a vehicle’s occupants during a collision. The airbags cushion the occupants from striking objects such as the steering wheel, dash board and windows during a crash. They have become vitally important to occupant safety and it is important that the fitment of a bull bar does not negatively impact on the correct operation of the airbag system.

The deployment of the Airbag is controlled by a central Airbag Control Unit (ACU). The ACU receives signals and information from several sensors and components in the vehicle including but not limited to various impact sensors and accelerometers as well as brake pressure and wheel speed sensors. Based on the information gathered from all of these sensors, the ACU may or may not trigger the deployment of the airbag based on its pre-programming.

In frontal collisions, the most important sensor involving replacement bull bars would be the accelerometers. These sensors are typically mounted near the front of the vehicle. Their purpose is to measure the rate of acceleration or in the case of a collision, deceleration. It is important to note that the original design of the front of your modern airbag equipped 4wd is very specific. The design and materials used will determine the crumple and therefore rate of deceleration during a frontal collision. The airbag sensors are programmed to measure this rate of deceleration accurately. The ACU will then base its decision to deploy the Airbags or not to deploy them based on this information.

A standard 4wd SRS system may be programmed to not deploy the airbags below a speed of 40km/h. During a collision below that speed, the complete system recognises the fact that this is a low speed collision and that airbag deployment is not required. Above that speed, the airbag sensors recognise a high rate of deceleration and the system deploys.

Removing the original vehicle bumper and replacing it with an all steel replacement bull bar changes the crumple zone at the front of the vehicle during a collision. Your bull bar equipped 4wd will now experience an altered rate of deceleration compared to the original vehicle during a specific collision.

At a speed of e.g. 38km/h, a vehicle fitted with a non-airbag compatible bull bar may experience a higher rate of deceleration due to the altered design of the front of the vehicle during a collision. The airbag sensors would now read the higher rate of deceleration as a higher impact speed than the actual impact speed. Your airbag sensors therefore think you are having an accident at a higher speed than the 40km/h threshold and trigger the ACU to deploy the airbags unnecessarily.

Unnecessary deployment of airbags is very costly to repair in addition to the damage to the front of the vehicle. Some insurance companies are starting to take note of this and will refute your repair claim should they find that your airbag has deployed prematurely due to the fitment of a non-airbag compatible bull bar. While airbags are there to help you during a severe accident, they are known to injure occupants that are in their way during deployment. You therefore do not want them to go off unnecessarily. Fitting a certified airbag compatible bull bar thus makes more sense.

Designed, engineered and tested in Australia.

Every Ironman 4×4 bull bar is carefully crafted from premium grade materials and components to deliver the most comprehensive frontal protection and styling available. Carefully modeled using precision 3D vehicle scanning techniques to achieve optimal cosmetic design whilst providing maximum vehicle collision protection.

All Ironman 4×4 bull bars are winch and airbag and ADR compatible to ensure you and your family’s safety isn’t compromised.

Contact us today for a quote & fitment. We have a fitment center at our Flagship Store in Alberton.

+27 11 634 7770 or sales@ironman4x4.co.za