The best overall Bull Bar. ? ?? ?

[antichrist]

Originally Posted by p76rangie

So when ARB state that it is airbag compatible, it is fact

Maybe in Australia, but not in the US. The word compliance means it complies with the law. There is no US Federal standard for air bag compliance of bumpers. So using the term in US sales is in fact 100% marketing. There's nothing to comply with.
That's like Land Rover saying their diesels are smog compliant...yes, they are, in the UK, but we still can't import them.

I believe that whether a bull bar is airbag compatible is very relevant to his needs as he drives a vehicle with airbags.

I don't, unless you, or anyone, can show me evidence of a "non-compliant" bumper preventing air-bags from deploying in a timely manner on a US spec vechicle.

Actually the thread is quite relevant to US customers because people keep bringing up "air-bag compatible" relative to bumpers as if it actually has any meaning whatsoever in the US market, which it doesn't.

[slangel]

Originally Posted by p76rangie

So I won't bother replying anymore.

Good

[Nomar]

We're not comparing the strength of a tubed roll cage or safety cage to a boxed RTE bumper.
That's apples v. oranges.
The tubed bumper you displayed is not stronger than the comparable RTE model.
No.
Way.

Looks better?

Uh.....not to most people. That last one you showed on the white Rangie looks like crap to me.
And probably most people.
At least the RTE looks like a bumper, not a bunch of pipes on the front of a truck.

[R_Lefebvre]

Originally Posted by Nomar

We're not comparing the strength of a tubed roll cage or safety cage to a boxed RTE bumper.
That's apples v. oranges.
The tubed bumper you displayed is not stronger than the comparable RTE model.
No.
Way.

Ever hear of triangulation?

As for the discussion of of relative strength of tube and pipe.... that's a difficult discussion to have.

For a given exterior dimension and material, square tubing is stronger in bending than pipe due to more of the material being further away from the centriod. But only in one direction. This is indisputable. Round tube is stronger in torsion, and also when the bending loads are not directly square to the tube profile.

However, square tube tends to be made from weak A36 structural steel. Whereas you can get much much MUCH stronger round tubing easily, such as 4130 DOM.

[TerryS]

Originally Posted by antichrist

I wouldn't go there. The largest crane derricks and booms are, in fact, made from round tubing. Which is best, round or square, depends on the application and expected stresses.

Good thing I said 'I think' eh Tom? I will admit I know little about strength of design. My specialty was strength of materials. Moment of Inertia, and Radius of Gyration were just words to me. Moments are what my wife has, and gyration, well you know where a sick mind like mine goes with that.
Terex Demag, and Grove were both good customers of mine, and we made the headstocks for many of their extension boom units. I believe Terex Demag still builds the largest mobile cranes, and none of theirs use round booms, same for Grove.
When I was in the MM, we lost a tug in the gulf and contracted the Whitte Heavy Lift, which at that time was the largest floating crane in the world (4000 metric tons, if I remember correctly). That boom was box beam. I remember someone saying the reason all the sailboats went to rectangular masts and booms was that resisted bending better, but I may be wrong again.
I always loved this hauler. Note the boxbeam construction on the trailer.

[antichrist]

Well, I'm not a structural engineer, but I was a rigger who assembled cranes on site, and the really large ones were square frames made from round tubing. But they are also fragile, relative to impact.

[TerryS]

Originally Posted by antichrist

Well, I'm not a structural engineer, but I was a rigger who assembled cranes on site, and the really large ones were square frames made from round tubing. But they are also fragile, relative to impact.

Like the one that went over in NYC a few weeks ago? I spent a whole afternoon in NYC (while my wife shopped for shoes) watching the riggers put one of those up. I agree that they use round tubes in the colum and boom construction, but when it's all together, the individual pieces become a part of the whole design, being square.
As far as being a strucural engineer, neither am I. Right now, I'm just a retired guy that makes maple syrup. Next month I'll be a landscaper.

[R_Lefebvre]

That trailer appears to be an I beam construction, actually. Strength to weight, I beam is even stronger in bending than box tube.

Some people are so hung up on shapes and thicknesses, but there is WAY more to it than that. Sure, one bumper might be made of 1/4" box steel. But what type of steel? A36 structural? Another bumper made out of 1/8" 1045 Cold Rolled would likely be just as strong. Factory bumpers are really thin, but these days they're made out of very advanced alloy, the steel is usually stronger than most crappy tool steel. Just try drilling a hole in a modern beam. Can't be done.

About the DII with the RTE bumper that hit the Focus. I question whether it was written off largely because the frame was bent due to the bumper being so stiff. We'll never know if a bumper mounted on crush cans might have saved the frame. It's the type of back to back testing that just never happens. One thing we CAN conclude, is that the bumper did not completely protect the truck. It's not the battering ram some people make it out to be.

I'd bet almost anything, ARB doesn't do full scale vehicle testing, at least not on all bumper designs. They likely test the crush strength of the existing cans, and mimic that with their cans. Then just run a few full scale collisions to confirm the theory. Full scale crash tests cost something stupid like $1M each. It's not just the vehicle you're wrecking, it's the equipment, manpower, etc.

As for the discussion on "compliance"... it's not about whether or not there are laws in your particular country. It's about whether or not the bumper changes the way the vehicle and SRS system work in a collision, and whether or not you personally believe you want "compliance" or not. Yes, it's 100% marketing, because there are no laws in the US. But it's a valid point. Do you want your SRS to work as the manufacturer designed it, or not. Simple as that. That's important to some people, and not to others.

A rigid bumper will make the airbags fire at lower speed, and also earlier in the collision. Maybe early enough that the bag will already be deflating by the time you reach it. That's the point.

I still haven't decided what I'm going to do. There's no perfect bumper. The ARB twist when winched hard and don't have any recovery points. The RTE's increase the likelihood of frame damage, and change the way the SRS works. I removed the airbags from my track car, which is still street driven. But then I have 5 point harnesses in that car and a crushable hub on the wheel, so hopefully I won't have a problem. Most importantly, my family doesn't ride in that car.

I've been in a severe frontal collision in a stock, modern car. With seatbelts properly fastened and seatbelt pretensioners, we still hit the airbags. I broke my arm on the dashboard. Do I really want to change the way all of that works when my family is in this thing? I dunno.

[atvsmurf]

everyone know round is stronger than square, why do you think they make wheels round instead of square, duh!!! each shape has its place, but take a sheet of paper and make a tube, then take another and make a boxed tube, tape both to retain the shape,which is stronger...

[R_Lefebvre]

Stronger in which direction? That's the key point to all this.

Guys, this is INDISPUTABLE. Square tubing of a given dimension and material is stronger in bending than round tubing. Period.

[TerryS]

Originally Posted by R_Lefebvre

I still haven't decided what I'm going to do. There's no perfect bumper. The ARB twist when winched hard and don't have any recovery points.

The ARB design on the 110 bumper I have is quite different than the one on my son's XD. They both have recovery points. What the 110 ARB does not, thankfully, have are the "wings" on the ones used on Discos and Classics.

I don't think mine would fair too well in a front end collision at any moderate speed, but in a 110, that's a moot issue, since the cab design of a 110 is pretty unfriendly to occupants in most accident situations. I do think, without any data to support it (I have no intention of looking up all that data, you guys can do it and I'll be happy) that if it were to fold up on impact, that may, to some degree, deplete some of the energy, rather than have it transmitted straight thru to the truck. As for the twisting when winching issue, I wonder how much of that is legend, bad press, as opposed to real. I certainly can only speak firsthand for mine, and my son's; they have no indication of twisting. Departure angle of the cable has a lot to do with that too. In the end, I like the look of mine better than 'most' others, and am happy to put the burden on myself for being a good driver, on or off road.

[sideview]

Originally Posted by p76rangie

It is good to see that you are a person that sticks to your views.
When you have nothing to support your views you just start name calling.

Nah, you were blabbering on about SUV vs. sedan safety & generalizing crash statistics. In proof of what, who knows, but it started to bore me

Show some evidence where a bull bar's (in particular an RTE's) airbag non-compliance was the direct cause of killing the driver/passengers then we can talk.

[R_Lefebvre]

Yes, you're not likely to fare well in your Defender in any case... frankly speaking.

I would also like to know more specifics on the bent ARBs. I suspect the problem is actually the crush cans bending. They are designed to be flexible, after all. Is your son's XD and airbag model? Because as far as I know, none of the airbag Arbs have any recovery points on them at all. Sorry, I stand corrected, it appears it's only the 03-04 model that has no recovery points at all... that's odd. Anyway, I would like to know the specifics. How hard of a pull was it and what kind of direction? But I'm not sure it even matters because I think you *should* be able to do a right angle pull if required. That's the point of a fairlead right? That's the design flaw of the ARB. The winch should be on a basket rigidly attached to the frame. Not mounted on what are essentially single use springs.

I like the design of the ARB the best in all regards save winch mounting, recovery points and jacking points. But, I'm not planning on anything extreme with the truck, that's what I have a motorcycle for. It's more overlanding, so protection is important to me. I just want to know if the ARB is "adequate" for my needs. Or is the winch mount so bad as to be a gimmick as some would suggest.

[R_Lefebvre]

Show some evidence where a bull bar's (in particular an RTE's) airbag non-compliance was the direct cause of killing the driver/passengers then we can talk.

Oh come on, that's impossible and you know it. Nobody collects data like that. Safety engineering is all done with comparisons and statistics. If you can't understand a statistic as simple as deaths/mile then there's no point discussing further.

What is immediately apparent is the survivability of accidents has greatly improved, due mostly to the advent of engineered crumple zones and active restraints. Anything you do that degrades those systems is a step backwards in time.

If you want to volunteer for live crash testing to prove your point, I think maybe they still do that in Kazakhstan so maybe you should go look for work there.

[antichrist]

Originally Posted by R_Lefebvre

Oh come on, that's impossible and you know it. Nobody collects data like that. Safety engineering is all done with comparisons and statistics. If you can't understand a statistic as simple as deaths/mile then there's no point discussing further.

You don't think that if there was any chance that a "non-compliant" bumper contributed to a death that the insurance companies would be all over it? They attributed 54 deaths directly to the fact airbags did deploy, I'm sure they figures would be there if anyone thought it was significant.

What is immediately apparent is the survivability of accidents has greatly improved, due mostly to the advent of engineered crumple zones and active restraints. Anything you do that degrades those systems is a step backwards in time.

Not sure what you meant to say, but airbags are a passive restraint system. I'm not sure I'd call an 8% increase in survivability since airbags have been mandatory "greatly improved".