PSA For you folks that are removing / modifying the crash bars to install bigger tires.....

[YaBoiNewton]

Yep lol. Also someone mentioned the bars may be made of Boron Steel and thus different metallurgy than the frame so not able to be welded to it...thankfully ?

These automotive HSLA steels generally play well together. I make some pretty nice welds with at least six different alloys. I've only had issues with alloys featuring high (>0.2%) carbon. If I had to guess I'd say the boron steel would make a super hard, brittle weld. Not very useful in a crash if your steel just breaks off!

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[Langwilliams]

hit me pretty square

Glad you came out of your accident OK but I don't think that is the kind of impact they are designed to protect against. You had the full frontal area, bumpers, bumper braces, crumple zones to absorb an dissipate the energy. The offset test drives a wheel straight back to the firewall. I wonder if the larger heavier tires dissipate more energy than the stock tires. So many variables involved an a lot of accidents come down to luck. Crash bars didn't help this:

 

[onobeka]

Yeah I can't speak for the specific details of the design. From experience with my own work there could be a million reasons to justify design choices that may not be obvious to others not involved in development. There were probably some other constraints that made fasteners a better design. Anything deeper than that is pure speculation.

Well, here is a speculation … the frame is global, USDM is predominantly preocupied by the safety of the “number one”, as long as the inhabitants of the cabin are protected, the rest is cattle. Mind you, the steel bumper can split a skull wide open. The ROTW rangers have plastic bumpers with foam absorption behinds. I guess priorities is a matter of interpretation. You may take this as a rant! It is, sort of, given it may be you or me hit by an over armored vehicle. Your explanation as an OEM engineer is bogus.

 

[Langwilliams]

The facebook video might not work but here's 2 pics showing a guardrail going through the engine bay an passenger compartment an out the back.

 

[YaBoiNewton]

Well, here is a speculation … the frame is global, USDM is predominantly preocupied by the safety of the “number one”, as long as the inhabitants of the cabin are protected, the rest is cattle. Mind you, the steel bumper can split a skull wide open. The ROTW rangers have plastic bumpers with foam absorption behinds. I guess priorities is a matter of interpretation. You may take this as a rant! It is, sort of, given it may be you or me hit by an over armored vehicle. Your explanation as an OEM engineer is bogus.

I don't work for the OEMs. I work for a supplier to the OEMs. Airbag inflators, specifically. You asked why they decided to use fasteners instead of welding - I'm saying it's not as simple as you're saying and I can't explain the design choice because I was not involved in making it. How is that bogus?

You keep changing the subject on me here, but you've touched on a good point regarding the automotive safety industry. It really is all about occupant protection, and often only for the highest bidder. The OEMs cringe to hear it, but poor people in all markets buying their cheap cars are inherently less safe than their wealthy customers buying luxury cars.

 

[Msfitoy]

So they can be removed when adding larger tires. ?

Just like Ford did with the 150 Raptor... ?

 

[D Fresh]

Why in the name of God would I purposely bring up something like this, that would otherwise NEVER even be a concern, to a greedy insurance company that would love to deny ANY claim for ANY reason. Naw I'm good.

The fact that you can acknowledge that it would be a bad idea to admit this to your insurance company proves that you understand the point being made by others.

Why are you continuing to ask others for proof of a possibility that you freely admit could happen?

At this point you're simply trolling. And doing a very poor job of it.

 

[D Fresh]

Crash bars doing what crash bars do…..

This picture is a perfect example. You can see from here that the bars did their job. Hell the tire is deflated right around the bar.

 

[JACKSMYDOG]

This picture is a perfect example. You can see from here that the bars did their job. Hell the tire is deflated right around the bar.

It proves the crash bars about as well as it proves the hood is stronger than the rest of the front end.

 

[D Fresh]

It proves the crash bars about as well as it proves the hood is stronger than the rest of the front end.

?

The hood is hinged and it's obvious from the windshield that it flew up. Which makes sense when everything the hood latches to is gone.

Not sure where I used the word "proves," but OK.

Of course it PROVES nothing. But it is quite obvious that the bars kept the wheel/tire from encroaching into the passengers compartment in this particular instance.

 

[JACKSMYDOG]

?

The hood is hinged and it's obvious from the windshield that it flew up. Which makes sense when everything the hood latches to is gone.

Not sure where I used the word "proves," but OK.

Of course it PROVES nothing. But it is quite obvious that the bars kept the wheel/tire from encroaching into the passengers compartment in this particular instance.

It's obvious the wheels stopped, not what stopped them.

 

[DukeCanBuildit]

 

[D Fresh]

It's obvious the wheels stopped, not what stopped them.

Sure, if you're not familiar with the structure behind the fender.

But we are.

What do you propose might have stopped the wheel if it wasn't the crashbar? The plastic flare? The sheet metal fender? The tire is literally deflated around the bar.

 

[JACKSMYDOG]

Sure, if you're not familiar with the structure behind the fender.

But we are.

What do you propose might have stopped the wheel if it wasn't the crashbar? The plastic flare? The sheet metal fender? The tire is literally deflated around the bar.

This was not a small overlap collision with all the force on the wheel. The entire front end absorbed the crash. Full width bumpers, crumple zones, Ranger both full length frame rails fully engaged, which allows very little force to be pushed through the wheels once compressed as it was.

There isn't enough force on the wheels in this type of crash to push them into the passenger compartment. If he had hit two concrete blocks, with a 4 foot gap between them, and all the force was on the wheels, which were then stopped by the crash bars, it would be more conclusive, but still needs a base line, and control group to define efficacy.

You could run vehicles without crash bars squarely into a flat wall hundreds of times without ever causing wheel to cab intrusion.

 

[D Fresh]

This was not a small overlap collision with all the force on the wheel. The entire front end absorbed the crash. Full width bumpers, crumple zones, Ranger both full length frame rails fully engaged, which allows very little force to be pushed through the wheels once compressed as it was.

There isn't enough force on the wheels in this type of crash to push them into the passenger compartment. If he had hit two concrete blocks, with a 4 foot gap between them, and all the force was on the wheels, which were then stopped by the crash bars, it would be more conclusive, but still needs a base line, and control group to define efficacy.

You could run hundreds of vehicles without crash bars squarely into a flat wall hundreds of times without ever causing wheel to cab intrusion.

Sorry, but I don't buy that explanation.

If the wheel/tire was not pushed back with significant force then why has it moved? Of course the bumper absorbed some impact. But if it absorbed it all the tire would not have been moved.

So despite the fact that this was a square collision, and despite the fact that the bumper absorbed some impact the wheel/tire obviously did indeed move. And it stopped at the crashbar, even if it wasn't the crashbar that stopped it.

Sidenote:


See @AdamHarris ?

This is how adults have a civilized discussion.

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