Safety considerations with steel bumper

[Doozi]

So your friend was 'Told' something after a crash. Again with the basic request for facts we get none. If you dont know, why are you talking about it. I dont see how any of that is true. So if i get in a wreck with a semi, how is it different. Its not like arb sells it with a bayonet attachment....good gravey do we all live in sue-ville or alternate fact land?

And by liable, you mean my insurance company. Not me actually. The bumper doesnt assume fault because of its material makeup. Is anyone here and actual underwriter so we can get some facts by page three.

The OP asked for thoughts on safety considerations regarding steel bumpers and I thought that I'd pass along something that I was surprised to hear. I said that I don't know the details, but suggested that it might be something worth looking into. Why don't you let the OP decide what is important to him?

 

[frodiesel]

Not as Utarded as you, apparently. I have no idea what you're trying to say here but if it's anything like the rest of your post I'm not missing much.

Basically the same as you, that a bling bumper wont change anything for the 'better' in the event of a crash. That force has to go somewhere. If nothing else, i learn more in the last few post.
Glad i raised my hand. I didnt know there was a difference in ARB bumpers.

I feel stock bumper is the best value in the event of a crash. Hence my for sale thread. I just think its easier to break out the facts instead of tossing generalizations around. Very sorry we even have to talk about this subject. Drive safe, if vehicles are weapons than mustangs are WMDs.

The internet will decide whose opinion matters. Or we can both build 4runners with different bumpers and have a head to head TR4 joist to settle it, and we'll both build toyota themed robots to drive the vehicle so we dont get hurt.

I wouldnt install more weight upfront or a bumper that could do more damage (think Tr4 robot joist like in cable guy) without a front tundra brake upgrade.

 

[KidVermicious]

Robots are always the answer.

 

[Morphyne]

Good discussion fellas. Here is what I gleaned from this conversation and my already cemented suppositions. Steel bumpers would be most effective in low velocity accidents and deer strikes. But adding the extra weight will increase stopping distance and decrease manuverability (crash avoidance). The solidity of the steel bumper may prevent airbag deployment. Which I think is huge considering that the air bag is an enormously valuable safety feature.

Thank you for your input.

 

[S4TA]

I think the biggest downside is in a low speed impact with a large object (F-250, tree, etc.) you are more likely to get frame damage as you don't have the super low impact crush cans to project the frame (crush cans don't protect you, and were not designed to do so). Modern frames are designed to crumple.

Similar to this, many years ago, a friend left his hitch ball in and backed into something. He bent his frame doing so. If he hadn't had it in, the bumper would of absorbed it with no damage. He never got it fixed because it was too expensive.



Sent from my iPhone using Tapatalk

 

[BlackWorksInc]

Having seen a few pictures of our tricks with steel bumpers getting into front end collisions, the front bumpers stay intact very well and usually protects our trucks from a lot of damage. I would guess that would come at a cost of a harsher impact or more damage to the other vehicle since you eliminated any crumple effect of your flimsy stock bumper.

Good discussion fellas. Here is what I gleaned from this conversation and my already cemented suppositions. Steel bumpers would be most effective in low velocity accidents and deer strikes. But adding the extra weight will increase stopping distance and decrease manuverability (crash avoidance). The solidity of the steel bumper may prevent airbag deployment. Which I think is huge considering that the air bag is an enormously valuable safety feature.

Thank you for your input.

Here's the deal, the full metal bumper will provide better cosmetic protection in low speed/low force impacts. In higher speed/higher force impacts inertia will not be mitigated nearly as effectively as with the factory bumper and bumper skin.

The reason for this is that you've removed the bumper skin, bumper itself (the aluminum bar), the bumper supports (which are designed to crumple as well before the frame sustains too much damage), and the foam pad. All these are designed to deflect and crumple to reduce inertial forces in an impact, the steel bumper for the most part bypasses that (because it attaches to the frame as a rigid piece and replaces all the above components) and thus the vehicle will come to a more abrupt stop compared to if it had factory components installed.

This is critical to understand because it is the real difference and trade-off you get with this modification. SRS sensors measure force and speed, they map the initial impact and then the deceleration values that are sent to the SRS module. The module then determines if it needs to take steps to arrest the occupants in the event of an impact to protect them. For example, if you're not wearing your seatbelt the SRS system may pop only the pre-tensioners in a decent impact rather than blowing the airbags as well; but if you're not wearing a seatbelt it may pop the airbags in a low speed collision because it has no other way to protect you. This also translates to the forces imparted from the steel bumper, the deceleration value may be different enough in a decent impact that the SRS system may pop the airbags to protect the occupants where in a stock vehicle it may not have done so. That's not something that's easily predicted or mapped out, but it does change those sensor inputs because of the physics.

More critically something that is often overlooked in these discussions is the effect on the occupants. Yes the steel bumper will protect the vehicle better for the most part (because it's not designed to essentially break-up like the factory components), but there's a trade-off to that. The trade-off is a far more abrupt change in inertia when the vehicle is in an accident. What I mean by this is that the vehicle will come to a rest far quicker than it was designed to, that imparts a higher risk of damage to the occupants. The human body is squishy and our internal organs are suspended in sacs within a large cavity, when the vehicle stops (as in it's come to a rest after an impact) our organs will continue to keep moving at the same rate until they hit something, usually the rib cage. The biggest reason behind crumple zones, airbags, and so-on is to try and reduce the difference in inertia as best as possible and reduce internal organ damage. Which means in lower speed collisions there's an increased risk of internal organ damage and hemorrhaging because of that lack of energy absorption that the stock crumple zones provide.

Just food for thought. I personally run a steel bumper on my 4Runner, but I am also aware of the trade-off I am making; I just hope that the risk is more minor than major.

 

[bob3dsf]

I know there aren't enough studies on this, but understanding physics and how crumple zones work, I'd be fine with a family member adding armor, and if I had to take a frontal impact, I'd take armor over non-armor 10 times out of 10.

A good buddy of mine is an EMT, and he told me he would never own a truck without a front armored bumper. Obviously that is just an opinion, but after some of the accidents he has seen, I will give it some deference.

^^This is a total non sequitur. I don't believe it merits deference.

I'm 12 year firefighter/EMT with technical rescue experience. I rode a ladder truck for several years which ours are equipped with extrication gear (so we went on all MVA's on our side of the city, and were secondary coverage for the rest of the city), my current assignment is an engine company which covers an interstate beltline. I've also been to Ron Moore's "University of Extrication." So there are my creds..

The comment on only driving with an armored bumper doesn't make a lot of sense. It makes a little I suppose, but only a little. Your buddy is basically saying decades of expensive R&D into crash safety, impact dynamics, testing and eval...etc.... is a load of crap. A lot of math an physics were a part of that and I'd say there have been many studies. As an EMT, he should know better then that. I'll link a youtube video with a crash tests between a modern car with crumple zone technology and all the doo dads and a 1955 Chevy Bel Air. It totally debunks the "conventional wisdom" or "common sense" that a big heavy mass of steel is safer in a crash then the modern cars. I can say unequivocally that I have rolled up on MVA's where, from my vantage point as we arrived, I though almost sure there was a fatality. In many cases the occupants were either unharmed or had mild to moderate injuries. Bottom line is that modern design protects the integrity of the passenger compartment. That is how you have the best chance to survive a crash. Sure, the car is going to look mangled to hell, but.... R&D. That's what it's supposed to do.

Its incumbent on you (the occupant) to wear your seatbelt. SRS technology is supplemental only (thats what the first "S" stands for in SRS) and can fail to operate correctly. Even if pre-tensioner doesn't fire, the seat belt will still do it's job just like they did before PT's. I have seen broken clavicles and ribs from the seat belt, but only a few times. The surest way to die in a crash is be ejected. The surest way to do that is don't wear your belt. All the ejections I've seen were due to not wearing a seat belt. Also, I've not yet had someone survive an ejection. And..., it's messy.

An offroad bumper is for cosmetic protection of the body, mounting points for winches, lights, jerry cans, larger tires, etc. Crash protection, I'll wager, is maybe a tertiary consideration if at all. The post about the 2 types of ARB's is interesting. I wonder where that fits in their design priorities. And, what do other armor makers do? Do they even address preserving crumple zones? Just curious.

Trees? Just try not to hit them, you'll be in for a world of hurt. I've been surprised at the aftermath of a car vs. even a small tree. They don't have to be redwoods by any stretch.

You want steel though? Don't worry it's there. More and more cars have integrated zones of high strength steel alloys. It's in the door panels for side impact, in the A/B/C pillars for roll over protection, etc. That stuff is so strong that rescue tool companies have had to redesign to make tools that can cut that stuff. We had a pin-in wreck a few years ago that required an exothermic torch to get through the high strength steel. They could have used conventional cutters and spreaders in well thought-out locations, but it was extremely time critical. That was pretty bad ass. For a while afterwards you could still find the slag that melted into the asphalt, but I think that area got re-paved.

Blackworks brought up an important point. In every crash, there are 3 crashes occurring. 1. The impact of the car with whatever, 2. You impacting the interior of the car (*hopefully* seat belts and not: steering wheel, dashboard, windshield, and anything loose that is now flying around in there), 3. the collisions of your organs with the inside of your body. Like BW said so well, the auto makers have spent A LOT of money on crash safety and survivability. Off road bumpers are not really a crash safety product. But it is a viable selling point in a well developed marketing campaign...

The most effective safety equipment is between your ears. Use it, stay aware, understand no one is immortal, know that you aren't really in control of anything, know that you aren't as good as you think you are, slow down, stay calm, turn off that F***ing phone, consider others.....

https://www.youtube.com/watch?v=xtxd27jlZ_g

 

[RonJR]

^^ Excellent post, especially the last paragraph. I've always said that multiple car collisions almost always involve the failure of two drivers. The first driver makes some mistake of inattentiveness, bad judgment, stupidity, etc., and the 2nd driver hasn't adequately provided room in his/her driving style to allow such mistakes to occur harmlessly. When both of those lapses occur simultaneously you get an accident.

 

[alhang]

i was curious about bob3dsf's post. why did they make 2 types of bars for a while and found this. ARB 4×4 Accessories | ASK ARB - air bag compatibility - ARB 4x4 Accessories

looks like in 1989 australia passed some safety law so equipment had to be compliant to ADR69, so a lot fo their bull bars in the 90s were made compliant. i personally chose the non air bag one because it was cheaper and i just wanted a winch mount. i still have it but i got a kid and family now and this post has me leaning towards a newer arb.

 

[bob3dsf]

i was curious about bob3dsf's post. why did they make 2 types of bars for a while and found this. ARB 4×4 Accessories | ASK ARB - air bag compatibility - ARB 4x4 Accessories

looks like in 1989 australia passed some safety law so equipment had to be compliant to ADR69, so a lot fo their bull bars in the 90s were made compliant. i personally chose the non air bag one because it was cheaper and i just wanted a winch mount. i still have it but i got a kid and family now and this post has me leaning towards a newer arb.

Interesting read.

 

[wcjeep]

ARB is held to a different standard due to Australian laws as just previously posted. If installing a bumper, it would definitely be ARB. They are the only bumper that I have seen that claims Airbag compliant. There are probably others. Their stuff is well engineered. They don't throw on extra mass for just because. Be sure to use their bolts to the proper torque spec. I have an ARB bumper on my Dodge truck. Great tech. Not sure on the Toyota, with my Dodge I did upgrade to LED turn signal lights.