Will the air bags still function correctly if I replace my front bumper with something like a ranch hand front bumper?

Most bumper companies do not want the liability of dealing with this. The only way to know for sure would be to crash test the given vehicle with the bumper on it.

I believe ARB is the only company that crash tests their bumpers.

It really will depend on how the sensor functions on a given vehicle - I don't know if the air bag deploy sensors sense a shock or a proximity sensor?

If they were a shock sensor, I don't believe they would affect airbag deployment - but this is pure speculation on my part.

the single front SIR threshold/crash detection sensor is mounted on the front crossmember on the HD trucks. Look under and you'll see it...little tiny box with a a yellow "!" triangle on it, and a 'CPA' type connector. Its not mounted to the bumper in any way so by putting a ranch hand bumper on you are not 'disabling' the SIR system in any way. I do not know whether its a proximity sensor or "G" sensor. Its mainly there to simply supplement and back up what the SDM's (located under the drivers seat) own main internal accellerometer sees/detects.

HOWEVER....do keep in mind that the SDM and entire SIR system was designed around the crumple rates and decelleration forces when a frontal impact is sustained with a STOCK bumper. Obviously a stock bumper is going to act in a compeltly different way than a huge heavy duty replacment ranch Hnad bumper. Ranch Hand bumpers are great for daily abuse/deer/other small things that would dent or wreck a stock bumper. However in a severe frontal impact I would want a stock front bumper. Reason being that in almost all crashes, it is DECELERATION RATE (in G's) that hurt people. Not the physical crushing of the passenger compartment. Vehicles NEED to be able to crumple and ABSORB the impact, NOT deflect it...theres a huge difference. It would be easy to design a vehicle with a front end thats built like a tank/battering ram, so that in crashes the front end doesnt get wrecked at all. But think about it, with a front end like that, you'd literally "bounce" off whatever you crashed into. Would you rather decelerate from 45mph in .0001 of a second, or .5 of a second?? The difference in stress on the human body between those rates is HUGE...Nassdmax could give you the technical calculations used in figuring this out, but about 100 G's to the head is about what it takes to kill a person. Thats why so much engineering goes into front end structure and crumple zones. The front impact NEEDS to destroy and crumple as much of the front end as possible without actual physical intrusion itno the passenger compartment. If you see a crashed vehicle that has the whole front end compeltely destroyed and mashed in, but is sound and maintained structurally from basically the A-pillar back, thats the vehicle I would want to be in an accident in.

Thats why our HD trucks are so incredibly safe. Just the sheer weight of them alone makes them very safe. They carry SOO much inertia and energy when in motion that if they do hit something, their such huge amount of forward energy takes much more time and 'effort' (by the object that the truck hit) to slow down and decelerate for a stop than a tiny car that weighs 2,500 pounds. That little light car, its not gonna take much opposing energy to stop it, so therefore its going to decelerate much quicker and be more dangerous in a REAL WORLD crash.

The goverment's crash ratings are a complete joke IMHO. They are NO representation of a real world crash. They are conducted in a complete static test situation that will most likely never happen in real life. I mean come on, how often do car accidents involve hitting a solid non-moving brick wall at a steady 45mph directly head on??? :rolleyes: No, they are more than likely to hit another car or something dynamic. Yeah ok so the little Honda Civic got a 5 star crash rating or whatever, whoptee do. Now say it got a head on with a 1 ton duramax CC/LB dually that was loaded to max GVWR?? The heavy dmax has so much more force and momentum than the Honda that ITS going to push that little car out of the way so easilly and still maintain some "left over" intertia because the little Civic simply didnt weigh enough to completly absorb that huge Dmax's full inertia. Picture them going head on, they hit, the Dmax slows down and keeps going forward for a little bit, while the Honda is stopped dead in its tracks and actually starts getting pushed backwards. Sure the Honda has its special 5 star crash rating, but think about what kind of forces were exerted on that driver vs. the duramax driver?? Thats why the airbags in our HD trucks are much more depowered than say, a Tahoe's or 1500 Silverado's airbags. They dont need to deploy with huge force because the crash forces subjected on our bodies in heavy HD trucks are MUCH less severe than a lighter vehicle.

sorry im rambling on cause I find this stuff interesting, but basically my point is that the Ranch Hand bumper in a severe front impact is going to change the way the front end crumples, and not "give" as much in an accident as a stock bumper would.

but still tho, Its good you took this into consideration when looking at a bumper :) ;) Most people who buy the replacment front bumpers ignorantly view the situation as "well this bumper is built like a brick ****house, so Ill be much safer in any accident"

Again, our trucks are so heavy you'll be fine with a Ranch Hand bumper, I didnt mean to scare you and make it sound like the difference between life and death :) I think Its a good idea for really rural areas where you are cruising down empty roads with deer and other static hazards versus on the highwway or in busy towns with stupid drivers.

JMO

ben

Ben,

You're not rambling - you're providing some very good information.

I wondered if the replacement bumpers might cause the airbag to trigger at a lower impact, since they wouldn't absorb the crash and thus pass it on to the sensor. It would be kind of embarassing having your airbag deploy after hitting a shopping cart........):h

Dang that is a lot of reading, Ben you should made that book a sticky so you don't have to type it again.

wow! maxpower your right on!
:exactly:

Wow what a great reply. Clear and logical. Thanks.