Steel bumpers

[Baron von Teuchter]

I’ve always wondered, if you fit an ARB style steel bumper to a ladder frame vehicle it effectively replaces a crumple zone. Forces from an impact transfer directly to the ladder chassis, possibly making an accident more likely to cause serious structural damage to the vehicle and not just soft panels and plastic trim pieces.

Any thoughts? Am I talking bollocks?

 

[Dokatd]

I’ve always wondered, if you fit an ARB style steel bumper to a ladder frame vehicle it effectively replaces a crumple zone. Forces from an impact transfer directly to the ladder chassis, possibly making an accident more likely to cause serious structural damage to the vehicle and not just soft panels and plastic trim pieces.

Any thoughts? Am I talking bollocks?

Depends on where the crumple zone is designed into the vehicle. Many are part of the frame or a piece bolted in between the bumper and frame. At least on a ladder frame vehicle anyways. The stock Gren bumper is steel but it's fairly light gauge.

Regardless, I personally prefer not to have a crumple zone on my off-road vehicles.

 

[Baron von Teuchter]

Reason i ask is I want to avoid this happening again

Crumple zone did its job but a steel bumper might have had nothing but some paint scratched off it.

What are the chances the frame could have been damaged by a two tonne Land Rover sliding into me at 5mph?

Or what if it was a 30mph accident?

 

[mcdoogs]

I’ve always wondered, if you fit an ARB style steel bumper to a ladder frame vehicle it effectively replaces a crumple zone. Forces from an impact transfer directly to the ladder chassis, possibly making an accident more likely to cause serious structural damage to the vehicle and not just soft panels and plastic trim pieces.

Any thoughts? Am I talking bollocks?

No I don't think you are. The force that isn't absorbed by crumple zones goes somewhere.

I'd only add that in addition to structural damage to the vehicle, there is the little minor issue of those forces being transmitted to the meatbags inside the vehicles as well. It sucks to have to write off a vehicle with a bent frame, its sucks a bit more to write off a human

 

[Baron von Teuchter]

Good point.

I also wonder if it becomes more likely you’ll fire the airbags in a low speed impact.

 

[ADVAW8S]

Reason i ask is I want to avoid this happening again

View attachment 7889130

Crumple zone did its job but a steel bumper might have had nothing but some paint scratched off it.

What are the chances the frame could have been damaged by a two tonne Land Rover sliding into me at 5mph?

Or what if it was a 30mph accident?

Couple of the off road bumpers like dissent and Owl out the USA, are moving the cooler higher. This helps lower damage or length of repair

 

[Tinerfeño]

The stock Gren bumper is steel but it's fairly light gauge.

The outer parts do have two thin steel plates but they are not even connected. It is VERY weak.

I doubt that there is a crumple zone in the chassis. Usually cars with chassis are worse in collisions than monocoque body.

For the airbags there is a speed limit below what the system deactivates itself. Never seen an airbag blowing in off-road, even with steel bumpers.

 

[DaneJa]

The center section of the OEM bumper has a crumple zone in it. You can see this on one of the YT videos where they swap the center section for a winch mount, though I can't recall which manufacturer it was. The sides are just thin stamped sheet metal.

 

[Zimm]

Depends on what your hitting. If you’re hitting another car, and your frame is stiff enough, the energy may cause that car to crumple more, and kill them. I surprised those of us that have heavy bumpers are not sued for it in collisions.

 

[DaneJa]

A few years ago I was driving to work in my FJ62 with a full steel bumper. A guy pulled out in front of me from a side street and I T-boned him at 35 or 40 mph. Totalled his car, he went to the hospital, and once it was all settled at the scene I continued on to work with a broken headlight and headlight valence and a bruised knee from the dash. There was seat fabric on one of the recovery hooks from the back of his driver seat -- could have been meat with a fraction of a second difference in timing. He was tagged for reckless driving and driving with a suspended license.

Lesson is, steel bar is good for you, not for them, at least at lower speed impacts and especially when your truck weighs twice as much, as will likely be the case.

 

[Dokatd]

The outer parts do have two thin steel plates but they are not even connected. It is VERY weak.

I doubt that there is a crumple zone in the chassis. Usually cars with chassis are worse in collisions than monocoque body.

For the airbags there is a speed limit below what the system deactivates itself. Never seen an airbag blowing in off-road, even with steel bumpers.

All vehicles imported to the US must have a crumpl zone either engineered into the frame or attached between the frame and bumper cover.

And airbags are not speed dependent, they must go off if the vehicle sustains a hard enough impact even if the vehicle is parked.

 

[Dokatd]

A few years ago I was driving to work in my FJ62 with a full steel bumper. A guy pulled out in front of me from a side street and I T-boned him at 35 or 40 mph. Totalled his car, he went to the hospital, and once it was all settled at the scene I continued on to work with a broken headlight and headlight valence and a bruised knee from the dash. There was seat fabric on one of the recovery hooks from the back of his driver seat -- could have been meat with a fraction of a second difference in timing. He was tagged for reckless driving and driving with a suspended license.

Lesson is, steel bar is good for you, not for them, at least at lower speed impacts and especially when your truck weighs twice as much, as will likely be the case.

Yep, this!!!

 

[Trialmaster]

Often thought about trying to acquire the American spec bumpers for our UK cars as they are metal and not as wide and thus visually more appealing.

Guess there will be a few surplus from those "upgrading" and maybe they would ship their castoffs to the UK?

 

[Tazzieman]

Depends on what your hitting. If you’re hitting another car, and your frame is stiff enough, the energy may cause that car to crumple more, and kill them. I surprised those of us that have heavy bumpers are not sued for it in collisions.

VW Kombi drivers would then be suing everything that hits them.
If they were still alive...

 

[Baron von Teuchter]

Often thought about trying to acquire the American spec bumpers for our UK cars as they are metal and not as wide and this visually more appealing.

Guess there will be a few surplus from those "upgrading" and maybe they would ship their castoffs to the UK?

I quite like the deep UK/EU bumper. Looks a little odd granted but useful seat / step and function beats form for me in a vehicle like this, it’s not exactly a Miura or 246

 

[Tinerfeño]

All vehicles imported to the US must have a crumpl zone either engineered into the frame or attached between the frame and bumper cover.

I didn't say that there aren't those aluminium pieces between bumper and chassis. Can also be seen on rear bumpers. But the length of these is far shorter than the zones on body structures.

 

[Tinerfeño]

And airbags are not speed dependent, they must go off if the vehicle sustains a hard enough impact even if the vehicle is parked.

Do you have constant power on SRS system?

 

[Zimm]

Do you have constant power on SRS system?

He likely intended to say stopped.

 

[Coullabus]

I’ve always wondered, if you fit an ARB style steel bumper to a ladder frame vehicle it effectively replaces a crumple zone. Forces from an impact transfer directly to the ladder chassis, possibly making an accident more likely to cause serious structural damage to the vehicle and not just soft panels and plastic trim pieces.

Any thoughts? Am I talking bollocks?

Would the change have implications to your insurance premium?

 

[Dokatd]

He likely intended to say stopped.

Yep, I kinda knew this would be confused, just let it ride anyways. Airbags will go off any time the vehicle is on and a person occupies a seat. That regardless of speed.