Thread: Airbag trigger/bullbar

I know a D2 has an inertia switch somewhere that doesn't rely on bullbar crush cans or whatever.

I don't know about a D1 but I think by the stage that the later ones were introduced the need for crush cans was repalced by inertia switches.
Regards PhilipA

Originally Posted by PhilipA

I know a D2 has an inertia switch somewhere

Under the console, I believe. My D1's ARB bar has crush cans, but it's a 94 and only has a driver's pyrotechnic.

Fitting a non-SRS bar has the following implications:

1) Insurance; vehicle becomes unroadworthy
2) Crash pulse changes; in an impact pulse timing of the SRS deploying can be altered.

Now on point 2:
An SRS pyro has the equivalent force of a Claymore (mine).
It is designed to deploy at the exact rate to be fully inflated before your body impacts it, therefore cushioning your chest/face as it slowly deflates.
If it goes off early, we’ll, you may just smash into the steering wheel.
If it goes off just a fraction late, it will strike your chest/jaw with the claymore force.
Not uncommon for SRS to break jaws/wrists/ribs/sternum, especially when an incorrect seating position is used by smaller stature drivers (too close to the wheel to reach pedals).
Something to think about when buying a vehicle for partners etc..

Originally Posted by Tombie

Fitting a non-SRS bar has the following implications:

1) Insurance; vehicle becomes unroadworthy
2) Crash pulse changes; in an impact pulse timing of the SRS deploying can be altered.

Now on point 2:
An SRS pyro has the equivalent force of a Claymore (mine).
It is designed to deploy at the exact rate to be fully inflated before your body impacts it, therefore cushioning your chest/face as it slowly deflates.
If it goes off early, we’ll, you may just smash into the steering wheel.
If it goes off just a fraction late, it will strike your chest/jaw with the claymore force.
Not uncommon for SRS to break jaws/wrists/ribs/sternum, especially when an incorrect seating position is used by smaller stature drivers (too close to the wheel to reach pedals).
Something to think about when buying a vehicle for partners etc..

Hi Mike,
Thanks for your input.
I'm fully aware of the force and timing, hence the question.
Do you know what actually triggers the airbag?
Given the range of things you could hit to trigger the airbag, from an immovable old gum tree to small light car with crumble zones, how does the system get the timing right, and how does a bar attached to your car change that.
How do the bar manufacturers get this right, I'm sure they aren't crash testing every vehicle they make a bar for, or are they?

Tony

Originally Posted by Tombie

Not uncommon for SRS to break jaws/wrists/ribs/sternum, especially when an incorrect seating position is used by smaller stature drivers (too close to the wheel to reach pedals).
Something to think about when buying a vehicle for partners etc..

Which is why they SHOUT about not fitting baby capsules to the front seat. Imagine how it is in the US, Mike, where there is no first "S" in SRS. Here, seatbelts, correctly worn, are designed to do the heavy lifting.

Very good points about legality and insurance.

Originally Posted by Tins

My D1's ARB bar has crush cans,

After the driver choosing to hit the bank on the side of the road rather than the oncoming logging truck these needed replacement. ARB still had them ( around 2012 ). $150 each....

Originally Posted by TonyC

Hi Mike,
Thanks for your input.
I'm fully aware of the force and timing, hence the question.
Do you know what actually triggers the airbag?
Given the range of things you could hit to trigger the airbag, from an immovable old gum tree to small light car with crumble zones, how does the system get the timing right, and how does a bar attached to your car change that.
How do the bar manufacturers get this right, I'm sure they aren't crash testing every vehicle they make a bar for, or are they?

Tony

Accelerometer within the cabin.

Timing is based on a few variables and calculated.
The bar is mounted with crush cans, with a known deceleration rate, just as is the rest of the vehicle.

A crude analogy….

You hold a big dense foam pillow to your chest.
You are then struck in the chest with a heavy mallet at a precise speed.
The pillow will absorb some of the force before you feel the impact.
Now, remove the pillow, replace it with a solid metal plate…

Originally Posted by Tins

After the driver choosing to hit the bank on the side of the road rather than the oncoming logging truck these needed replacement. ARB still had them ( around 2012 ). $150 each....

I repaired mine after a hit on the LH side



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