Aftermarket front bumpers and air bag systems

[offthebeatenpath]

So I thought I'd throw this out there to the www and see what kind of a response it gets-

I know that ARB bumpers are advertised to work in conjunction with factory air bag systems.

Can someone explain to me how that works?

Are there any other aftermarket bumper manufacturers that even mention air bag systems?

 

[enzo]

I'm pretty sure ARB has that info on their site. I don't know of any other airbag compatible bumpers.

 

[Dave Bennett]

Everything you want to know is on my site in the ARB bull bar page.

 

[Utah KJ]

I believe that the bumper "gives" in a heavy collison and doesn't set off the airbag prematurely like other solid bumpers can. In other words, the airbag can be set off in a lesser accident with a solid bumper. Airbag compliant is not important until your insurance company tells you to ****** off when you ask them to pay the bill for new airbags.

 

[Mrknowitall]

Airbag compliant is not important until your insurance company tells you to ****** off when you ask them to pay the bill for new airbags.

Have you actually known this to happen? If so, how did that play out?

 

[1911]

All it means is that ARB has spent the money to have their bumpers crash tested, and most (all?) other bumper manufacturers have not.

The airbag deployment sensors are not in the bumper, they are behind it somewhere (on the frame?), so no aftermarket bumper will directly interfere with the deployment of the airbags - the question is, how do different bumpers transfer energy through to the sensors versus the way the stock bumper does? Having personally removed a ton of stock FJC bumpers and replaced them with various aftermarket ones, I'm guessing there is not much difference, but to an automotive engineer maybe it is a big difference for all I know. I'm not losing any sleep over the Demello bumper on mine in any event; it has proven it's worth over the stock bumper many times in the last five years and 130,000 miles.

 

[offthebeatenpath]

I believe that the bumper "gives" in a heavy collison and doesn't set off the airbag prematurely like other solid bumpers can. In other words, the airbag can be set off in a lesser accident with a solid bumper.

The airbag deployment sensors are not in the bumper, they are behind it somewhere (on the frame?), so no aftermarket bumper will directly interfere with the deployment of the airbags - the question is, how do different bumpers transfer energy through to the sensors versus the way the stock bumper does?

I guess these two statements are a much more articulated form of my initial question.
Yes, I get that a bumper such as your Demello will infer less body damage to my Taco in minor collisions, but how would it interfere with the SRS system in a more major collision where the air bags should/would be set off?

Would it cause the air bags to be set off prematurely or too late? Or is that just a big fat unknown which ARB is addressing by stating that their bumpers don't interfere with SRS systems?

 

[offthebeatenpath]

Here's the statement off of ARB's website:

AIR BAG COMPATIBILITY

With an air bag equipped 4x4 it is essential that the vehicle's crush rate and air bag triggering is not altered when a bull bar is installed. To ensure compatibility, ARB assesses each vehicle's frontal crush characteristics and replicates the crush rate into the design of each air bag compatible bull bar and its mounting system. This method enables engineers to achieve maximum possible vehicle and passenger protection without affecting the crash pulse. ARB has invested heavily in vehicle crash barrier tests to validate the performance and compliance of its air bag compatible bull bars, and as a consequence, our bars offer a far greater level of protection than most standard brush guards and grille guards.

Please note that a few of the bumpers for older model vehicles are not air-bag compatible, refer to the Vehicle Application Guide for confirmation.

 

[1911]

Yes, I get that a bumper such as your Demello will infer less body damage to my Taco in minor collisions, but how would it interfere with the SRS system in a more major collision where the air bags should/would be set off?

I couldn't say, since I've never been in a major collision with mine. My inference of value is simply from the number of times my aftermarket bumper has saved me from trail rash and from being stuck, versus the odds of being in a major collision on the road (apparently quite low in my case). I like the every-day usefulness of a good steel bumper and I'm willing to accept the (minimally?) greater odds of something possibly imperfect in the SRS system as a trade-off.

Would it cause the air bags to be set off prematurely or too late? Or is that just a big fat unknown which ARB is addressing by stating that their bumpers don't interfere with SRS systems?

For most of us I think it is a big fat unknown, but I'm willing to give ARB the benefit of the doubt up to a point, if they've really done more homework and testing than other folks and it's not just a marketing ploy.

Here's the statement off of ARB's website:

AIR BAG COMPATIBILITY

... To ensure compatibility, ARB assesses each vehicle's frontal crush characteristics and replicates the crush rate into the design of each air bag compatible bull bar and its mounting system. ...

Personally, I find this a little hard to believe, though I am just an old mechanic, not an automotive engineer. The stock Toyota FJC front bumper is just a sheet metal box bolted to the frame, and covered by plastic and air. On the other hand, the ARB bumper is one of the heaviest (ergo with the most steel) in the whole aftermarket industry. No doubt in my mind that it is a quality piece, but I also don't see how it could possibly "replicate the crush rate" of the stock plastic, air, and sheet metal.

 

[Rotorgeek]

Here's the statement off of ARB's website:

AIR BAG COMPATIBILITY

With an air bag equipped 4x4 it is essential that the vehicle's crush rate and air bag triggering is not altered when a bull bar is installed.

Why do I read this as "Our bumper provides no additonal strength or protection than the stock bumper."

 

[Applejack]

Why do I read this as "Our bumper provides no additonal strength or protection than the stock bumper."

I have no idea why you read it that way. Keep in mind ARB, TJM, AllPro bumpers are for vehicle protection, not to be confused with passenger protection. ARB has spent the money to have their products engineered so as to not interfere with air bag deployment, meaning that the airbags deploy when they are supposed to. Modern airbag systems have gotten quite a bit more complicated than when first introduced. Crush sensors in the bumper, decelerometers etc. all computer monitored, you can begin to see that there could be several ways an aftermarket hunk of steel could interfere. Factory plastic bumpers are designed to absorb a certain amount of impact before transferring that energy down the line. From what I can tell on my ARB the mounting brackets are where the impact would be initially absorbed, by way of their accordion design. With out these it is easy to see how a small "bump" may cause premature deployment, while a poorly designed bumper that was weak in the center and focused energy that direction, may have late airbag deployment because the bumper absorbs too much energy before tripping the sensors.
This is all hypothetical but plausible and I'm sure has happened. What are the odds?....... For me, the real question is; Do I want to leave my and my families safety in an accident up to a proverbial coin toss, simply because I wanted a bumper that looked cool? NOPE! For now I'll stick with ARB. How do other companies bumpers stack up? I wouldn't even try to say, they may do just as well as ARB but I don't want to be the crash test dummy that finds out. Furthermore I would think that improper installation of an ARB bumper could be just as detrimental especially when you have to make frame modifications as you do with 3rd gen 4runners.

Quote Originally Posted by Utah KJ View Post
Airbag compliant is not important until your insurance company tells you to ****** off when you ask them to pay the bill for new airbags.

Or when you bump a rock or tree and your airbag deploys early, smashing you in the face and burning your arms.

 

[bat]

while a poorly designed bumper that was weak in the center and focused energy that direction, may have late airbag deployment

I was at an auto body shop yesterday newer 4runner dead center hit by a tree perfect 2' round circle bent the frame horns and no air bags deployed. My buddy who owns the shop was pretty amazed the air bags did not go off with that big of a hit.

 

[Finlay]

I was at an auto body shop yesterday newer 4runner dead center hit by a tree perfect 2' round circle bent the frame horns and no air bags deployed. My buddy who owns the shop was pretty amazed the air bags did not go off with that big of a hit.

When I was in college, I attended a talk where an automotive engineer from Lexus described how the computer is programmed to use the minimal amount of passenger restraint. The are a couple of reasons for this - cost, and chance of injury, etc. - but mainly it's to reserve some additional restraint in the case of secondary collisions.

So, depending on the accident, you shouldn't expect the airbags to go off.

 

[Silver-Bolt]

The difference is at low speed impact. The ARB uses the factory crush cans where some of the others do not. The airbag sensors are inertia triggers. Meaning that is takes a certain amount of G-Force to set them off. There are several other factors but they are not related to the bumper. DOT requires that a bumper has to survive a 5 mph impact with minimal damage. The crush cans absorb the energy from the impact reducing the G-Force transmitted to the occupants. Without the crush cans 100% of the impact is transfered which is more likely to trigger an airbag in a low speed impact. ARB retains the cans so the it retains the factory carachteristics. With some other brands thet ommit the cans and are mounted solid to the frame. The high speed results are the same as stock however at lower speed impacts the bag trigger may be more sensitive.

 

[Utah KJ]

All it means is that ARB has spent the money to have their bumpers crash tested, and most (all?) other bumper manufacturers have not.

The airbag deployment sensors are not in the bumper, they are behind it somewhere (on the frame?), so no aftermarket bumper will directly interfere with the deployment of the airbags - the question is, how do different bumpers transfer energy through to the sensors versus the way the stock bumper does? Having personally removed a ton of stock FJC bumpers and replaced them with various aftermarket ones, I'm guessing there is not much difference, but to an automotive engineer maybe it is a big difference for all I know. I'm not losing any sleep over the Demello bumper on mine in any event; it has proven it's worth over the stock bumper many times in the last five years and 130,000 miles.

The deployment sensors location has nothing to do with how the sensors work when you change the bumper.