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Replacement bumpers and airbags

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Old 12-15-2006 | 08:14 AM
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Default Replacement bumpers and airbags

I noticed when I was looking at the page for the AEV bumper it specifically says it has locations for the airbag canisters.

Is this something most replacement bumpers don't have? This is something that I've never even thought about.

If replacement bumpers don't typically have mounting spots what do people usually do about it? Just disable the airbags and forget about them?

Beel
Old 12-15-2006 | 08:31 AM
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Most of the aftermarket bumpers do not have provisions for the new air bag crush cans that come on JK. The TJ's (or at least my 2000 TJ) did not come with these. From what I've been told, these crush cans are located behind the bumper pads and are used to determine the intensity of a crash - but I have not been able to verify this for sure.

Having said all that, the question I've got going through my head is whether or not this is a good thing to have especially if you plan on playing hard on the rocks. And, I'm really curious to know how important a feature like this would be to all of you. Would you prefer to keep the crush cans, have the opition to keep them or do you even care to have them?

Please let us know as I'm sure your voice will help to shape how this industry proceeds in the near future.
Old 12-15-2006 | 08:47 AM
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Originally Posted by wayoflife
Please let us know as I'm sure your voice will help to shape how this industry proceeds in the near future.
Well I've been considering this issue too. I was thinking about getting new bumpers too, but now I'm having second thoughts because of the effect on the airbag system. I won't be doing any rock crawling, only mild off-roading, and I just feel better leaving the system as it was designed. So for now I think I will just spend my money on other upgrades and mods.
Old 12-15-2006 | 08:52 AM
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That was one of the thoughts I had after I read about the airbags. That would suck to be on the trail and bump a rock or something and have it go off in your face.

However, airbags are certainly an important safety feature and I'd rather have them if I was in an accident. How does this affect insurance? If you're in an accident and the insurance company finds out you've removed or disabled safety features will they refuse to process the claim?

I realize these issues are just part of the reality of owning a modified off-road vehicle but my preference would be to have working airbags even with a replacement bumper. I'd rather deal with the potential mis-fire on the trail than no protection in a highway accident.

On a side note, this is unfortunate because I didn't really care for the look of the AEV bumper. My personal choice was the PureJeep. Guess I'll have to re-think this.

Beel
Old 12-15-2006 | 08:54 AM
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The new AEV bumper does supports retaining the "airbag crush cans"...

I'm reasonably certain these are not some kind of electronic component that measures impact force. They are simply an engineered shape that will deform (or crush) under a certain amount of force. By doing so they absorb a specific amount of crash energy before it is transmitted to the rest of the vehicle. By doing so, they are part of the calculations the airbag controller uses to decide when to fire the airbags.

I do think the AEV picture of the front bumper is interesting in that it shows the bumperettes that contain the crush cans... and right in between is the roller fairlead for the winch. I would think this item sticking out ahead of the crush cans will "mess up" the true functioning of them.
Old 12-15-2006 | 09:12 AM
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Originally Posted by jdrogers
I do think the AEV picture of the front bumper is interesting in that it shows the bumperettes that contain the crush cans... and right in between is the roller fairlead for the winch. I would think this item sticking out ahead of the crush cans will "mess up" the true functioning of them.
I was wondering what those were.

I'd guess they were mounted like that so it doesn't require such a severe impact to trigger. The aftermarket bumpers are heavy gauge steel and I'm sure it's going to take a pretty serious impact to crush a can mounted behind them.

Beel
Old 12-15-2006 | 09:15 AM
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Okay, I just made a few calls to get me schooled on how the JK airbags work and here's the scoop. The two forward most bump pads on the JK front bumper are the crush cans. There are no electronic sensors or wiring of any kind in them and replacing your front bumper with an aftermarket one will NOT disable your airbag system.

All the crush cans are designed to do is to absorb a certain amount of impact before a collision reaches the frame. If the frame is hit, a gyro sensor in the center of the vehicle will swing forward activating the airbags. In essences, the crush cans help to regulate when to deploy your airbags. BUT... here's the kicker, in order for the crush cans to work, you would have to make direct impact with them. Needless to say, if you hit something like a pole dead on, you will miss the crush cans all together. Do you see where I'm going with this?

Bumpers like AEV's or Mopar's simply have the forward bump pads or crush cans built into them just like the factory bumpers and they will help the airbag system to know not to deploy under certain conditions but only if you hit them directly.

Bottom line is, buying an aftermarket bumper without these crush cans will NOT disable your airbags.
Old 12-15-2006 | 09:20 AM
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Originally Posted by jdrogers
I do think the AEV picture of the front bumper is interesting in that it shows the bumperettes that contain the crush cans... and right in between is the roller fairlead for the winch. I would think this item sticking out ahead of the crush cans will "mess up" the true functioning of them.
Oh, that's just precious!! Yer pretty damn observant and funny to boot
Old 12-15-2006 | 09:23 AM
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Originally Posted by jdrogers
The new AEV bumper does supports retaining the "airbag crush cans"...

I'm reasonably certain these are not some kind of electronic component that measures impact force. They are simply an engineered shape that will deform (or crush) under a certain amount of force. By doing so they absorb a specific amount of crash energy before it is transmitted to the rest of the vehicle. By doing so, they are part of the calculations the airbag controller uses to decide when to fire the airbags.

I do think the AEV picture of the front bumper is interesting in that it shows the bumperettes that contain the crush cans... and right in between is the roller fairlead for the winch. I would think this item sticking out ahead of the crush cans will "mess up" the true functioning of them.
That was my thought exactly. How can the crush cans be in the bumper and then leave the fairlead out there.

I've taken the bumper off of my JK several times, and the crush cans are just two steel "soup" cans that are welded to the factory steel bumper structure... that is covered by the large plastic bumper.

There are no electronics that attach to them, and are meant to absorb a certain amount of energy, as stated above... but only in a dead-on frontal impact, where you hit something flat, solid and wide enough to crush the two cans.

Removing them won't keep the airbags from deploying, since the airbags are deployed when a certain amount of deceleration is reached... determined by an accelerometer and the ECU. That's a finite threshold, regardless of crush cans.

My though on offroading with airbags is that if you hit something hard enough to deploy them, you most likely will be happy they did. (My wife recently t-boned another car with her '06 Chrysler 300, at 25mph... the front was completely destroyed, but it wasn't enough impact to deploy the bags.)
Old 12-15-2006 | 09:23 AM
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Originally Posted by Beel_MT
I was wondering what those were.

I'd guess they were mounted like that so it doesn't require such a severe impact to trigger. The aftermarket bumpers are heavy gauge steel and I'm sure it's going to take a pretty serious impact to crush a can mounted behind them.

Beel
But that's just the thing, those black rubber pads are the crush cans and there is nothing behind the AEV bumper or any bumper for that matter. And, if you don't hit them, they won't do squat



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