By Mike Beiergrohslein (400mcs) on Thursday, May 31, 2001 - 01:40 pm: Edit

I recently wrecked my factory bumper on my 97 Disco, so I'm looking at the ARB. It seems that the non-ARB advantages over the air-bag version is 1)little stronger 2)requires less mods to install winces 3)cheaper, but it can suppress or accentuate the release of the airbag. Just wondering if anybody has had any bad experiences with the non-bag version that would justify me buying the air-bag version?
Thanks MB

By Rob on Thursday, May 31, 2001 - 01:45 pm: Edit

I ended up purcahsing the air bag ARB Bullbar but was told a couple of times by suppliers that the non airbag version does not really suppress the airbag. I have a small son so I did not want to take any chaces.
I got a really good deal on mine email me and I'll tell you where I bought it.

By Mike on Friday, June 01, 2001 - 12:56 am: Edit

I have had the opportunity to examine both style ARB bull bars closely.

The non-air bag ARB bull bar actually will deploy the airbag sooner due to it's lack of the crush zones. The winch sits more towards the top of the bumper which it makes it much easier to operate.

The air bag ARB bull bar moves the winch to under the bumper which makes the winch much harder to use. If you are stuck, you have to reach down and under the bumper to release the winch cable. This is a real PIA if you are stuck in deep mud or water. However, the air bag ARB adds an additional cross-member to the end of the frame horns to strenthen the way it mounts to the vehicle.

It's all about trade-offs and choices!

LoL,
Mike

By James Shackelford on Friday, June 01, 2001 - 01:21 pm: Edit

Mike,

I went for the non-airbag ARB. I have seen the airbag model bend on the trail in a situation that if shouldn't. Many people have told me that they (air-bag) are weaker.

In addition, from what I understand, the airbag is not deployed by the bumper but by multiple inertial sensors in the vehicle. One sensor by itself will not deploy the airbag, but multiple sensor activations will.

I figure, unless I hit a Redwood or a concrete wall, the protection the bumper gives is a tradeoff of the bags deploying a microsecond early. Also, I have seen a non-airbag ARB on a disco hit a dirt embankment pretty hard without the bags going off.

James
95' Disco

By Ron on Friday, June 01, 2001 - 01:37 pm: Edit

One more non-airbag vote is that the m12000 and M15000 will bolt right up to it. Airbag you are stuck with crappy little winches.

Ron

By Mike Beiergrohslein (400mcs) on Monday, June 04, 2001 - 02:17 pm: Edit

Since I'm moving to Alaska and there is such a high population of moose, maybe its best to buy the air-bag version so I don't get an early release?

By Joshua Bova (Jbova) on Monday, June 04, 2001 - 02:45 pm: Edit

I have the air bag version, and while I am happy with it in most aspects, the comments made by Mike concerning the difficulty accssing the winch are echoed here. If I were to do it again, I would mostlikely go with the non-airbag version.

The other option is the Josh Weinstein method of re-configuring the bumper to top mount the winch. Best of both worlds, and from a brief inspection it does not appear that his changes will dramatically alter the strength or air-bag capabilities of the bumper. You can see his changes in the tech section.

I like the idea that my air-bags won't go off un necessarily and if I do collapse the "crush cans" inside the bumper, they can be replaced without replacing the whole bumper. This is another nice touch. But I am sure that if you hit the something hard enough to deploy the airbags with the non-airbag bumper your last concen will be the airbags.

-josh

By Jon (Jonw) on Monday, June 04, 2001 - 02:50 pm: Edit

Well, if you hit a moose, you're probably gonna trigger something regardless of what's on the front of your truck. What I noticed about the two kinds of bars is the airbag-compliant one is designed to crumple sort-of, to absorb impact along with the crush can things. Some people think that makes it weaker, which structurally it is less rigid than its non-airbag counterpart. But the real issue between the two bars, especially the non-airbag one, is its inability to disperse force in an impact. The non-airbag bar will smash whatever you hit, and may not trigger the airbags at all, whereas it's airbag compliant sibling will crunch and give you the performance from the airbags Land Rover intended to minimize your injuries. So I guess what I'm saying is, if you don't really care about your airbags deploying in a frontal collision and would like a bar with some girth and utility and the ability to push some things out of the way (like mooses), get the full-strength ARB bar. If you place higher value on the safety of loved ones riding with you and would like to have the explosive cushioning action of the airbags when you plow-down said moose, get the airbag-compliant version.

By Gil Stevens (Gil) on Monday, June 04, 2001 - 03:04 pm: Edit

....so its not an issue of the airbags going off unexpectedly or to soon, its more a case of them not going off at all? Theres nothing wrong with that, if it was up to me, id rip the god damn things out anyway........

By Jon (Jonw) on Monday, June 04, 2001 - 03:15 pm: Edit

Correct. That non-airbag ARB bar will act like a battering ram to whatever it hits, and more than likely won't trigger the airbags at all. But like Josh said, if you hit something hard enough to deploy the airbags with the non-compliant bar, you'll need all the cushioning the airbags can offer. ...which, I feel, is the correct gauge for airbag deployment, since I use my bar to push stuff out of the way sometimes, and would we inconsolably pissed if my airbags deployed when using the airbag-compliant ARB bar to do the same work.

...just my $3.75...

By garrett on Monday, June 04, 2001 - 04:06 pm: Edit

I like my airbag......saved my hide for sure in my old '94 Disco. Hit a tree doing 40 mph head on. Walked away with a big lump on my head and some sore knees for a year.

By Rob Davison (Pokerob) on Monday, June 04, 2001 - 04:59 pm: Edit

the non-airbag arb bar is more likely to trigger the bags in a collision than the airbag compatible one, yes?

if the above is a false statement please explain.

rd

By Gary on Tuesday, June 05, 2001 - 09:14 am: Edit

Correct. Less force will be absorbed because it doesn't have the "collapsible" mounting-points of the airbag model.
Mid-96 onwards vehicles (gotta check the manual to confirm) only have an inertia sensor (mounted between the front seats) to trigger the bags, so the greater rate of deceleration of a non-SRS bumper will cause it to trigger in less-traumatic situations.
Vehicles prior to mid-96(?) have a crush-can towards the front of each of the frame rails as well as the inertia sensor. AFAIK at least one crush-can *and* the inertia sensor have to trigger in order to deploy the bags.

Apparently Federal law states that the *entire* SRS system (crush-cans if applicable, wiring harness, inertia sensor, bags, etc) needs to be replaced in the case of deployment. And airbags have to be replaced once they're 10 years old (something to budget for).

So remind me, which fuse do you pull to prevent low-speed off-road deployment?

Gary

By Jon Williams (Jonw) on Tuesday, June 05, 2001 - 09:22 am: Edit

Garret, interesting pic. I don't believe I've ever seen a Disco wrecked before. And Rob, the non-airbag ARB bar is less likely to trigger the airbags in a mild collision because it won't collapse and absorb impact like the airbag-compliant one will. The brackets that mount the bar (non-airbag) are quite rigid and won't crunch much in certain mild impacts, ones in which the airbag friendly ARB bar brackets and frame will crumple. This doesn't mean the non-airbag bars won't do damage to your truck - the part of the frame you mount the bar on will bend/crush some. The bar's design just won't allow the bar to crush enough to allow frontal damage sufficient to trigger the airbag sensors. For example, say you're driving along about 35 mph and somebody pulls out and you t-bone them. With the airbag friendly bar, the frame will crunch, the front of your truck will crunch, and your airbags will deploy. With the non-airbag one, you'll hit the car, the brush bar will bend your frame, but won't crumple like the airbag bar will, all your impact force will be transferred to the car you hit (and to your body) and you probably won't see any airbags hit you in the face. That's great for preserving your truck in an accident, but you could be seriously injured because none of the airbags deployed to cushion your iumpact.

By Jon Williams (Jonw) on Tuesday, June 05, 2001 - 09:25 am: Edit

Okay, it seems there's something different about the newer models of Discos. All my info is using a '94 - '95 model as basis. However, an inertia sensor (which is a dumb way of doing it) would definitely cause premature deployment of the airbag in mild collisions, for the reasons Gary said.

By liability ? on Tuesday, June 05, 2001 - 09:56 am: Edit

Jon & Gary, Yes, I can second your discussion about air bag deployment early with a non-airbag arb on the '96 & newer disco. A Land Rover mechanic in our local club has validated this same situation. Though I have not seen it happen first hand, I tend to remove the SRS fuse prior to heading off road. This is just to avoid the potential air bag deployment. You didn't hear it from me, but it's the fuse covered with a yellow plastic frame. Turn vehicle key off for at least 30 seconds, pull the fuse. Replace the same way, turn vehicle off for 30 seconds or more, and replace the fuse. When the fuse is removed the SRS dash light will be on (so you will know to replace it). I use this method on my NAS 1997 disco with no troubles, though I do not recommend this to anyone, so try it at your own risk !

By JEEPETR on Tuesday, June 05, 2001 - 10:02 am: Edit

Respectfully,

I must disagree Jon. The very function of the "Crush Cans" in the Air Bag compatible bumper, as well as the crumple zones built into the vehicle is to absorb some of the impact. This impact is seen (in the eyes of the SRS airbag system) as deaccelerative G's. The sensor will see a lower acceleration rate if the bumper/frame/body deform to absorb the energy as they are designed to do, and is less likely to deploy the bags in a low speed accident.

Now add the Rigid, non deforming ARB bumper. It deforms very little, transferring most of the energy to the trucks frame, which (in comparison to the vehicles crumple zones) absorbs very little energy. In this case, the inertia switch in the SRS system (that activates the bags) sees higher rates of deacceleration that it did in the case were the truck deformed, absorbing some of the impact, and therefore would be MORE likely to deploy the bags in the same accident.....

I actually did a long research paper on SRS systems a few years back....

~Scott T.
'95 D-90 (JEEPETR)
'96 Discovery (New addition to the Addiction!)

By Rob Davison (Pokerob) on Tuesday, June 05, 2001 - 10:05 am: Edit

i did not know that the early disco's have different sensors than my '97. this makes more sense.

rd

By Jon Williams (Jonw) on Tuesday, June 05, 2001 - 10:25 am: Edit

Well yeah, Scott, I know that now. I was under the impression that all Discos were equipped with the crash sensors as found on my '95 model, which are of the type that require a contact to be made internally to trigger the airbag system. Understandably, any inertia sensor is gonna have an amplified response when a rigid body structure fails to absorb impact energy.

By Blue Gill (Bluegill) on Tuesday, June 05, 2001 - 11:51 am: Edit

interesting discussion...so, for the record, which of the following is correct?

A) NON-Airbag ARB bumper is more likely to deploy airbags than Airbag-compatible ARB bumper in the event of a front end collision with an object (rock, dirt berm, tree, j**p, shopping mall, etc.)

B) Airbag-compatible ARB bumper is more likely to deploy airbags than NON-Airbag ARB bumper.......

I must admit that I always assumed the NON-Airbag model would transmit the most force directly to the Disco and therefore blow the bags more readily than the bumper designed with the airbags in mind - Scott's comments reinforce those thoughts...

Also, did anyone see the news report last night about the Ford F150 40mph head-on crash tests? The F150 scored the worst, with Dodge Ram a close second. The F150 was absolutely obliterated after a 40mph hit! Garrett, do you have any more pictures of your 40mph impact, particularly the passenger cabin? Did doors still work? Did firewall push back? What about the tree? Did it move?

By Jon Williams (Jonw) on Tuesday, June 05, 2001 - 12:53 pm: Edit

Knowing what I know now about the differences in impact sensors for different model years of Discoverys:

1) If your truck is a 1996 model or newer, you need to use the airbag-compliant ARB brush bar.

2) If your truck was made pre-1996, you can use the non-airbag version of the bar if it suits your needs, but be warned that the effectiveness of your SRS will probably be reduced in certain mild frontal impacts (i.e., it will take a substantial collision to deploy the airbags).

By Blue Gill (Bluegill) on Tuesday, June 05, 2001 - 01:14 pm: Edit

Yes, I did not take different sensors into account with my previous post...

But, the question remains: with which bumper will airbags deploy more readily (taking into account different sensors)?

By garrett on Tuesday, June 05, 2001 - 01:34 pm: Edit

This is all that I have on hand from an inside view. The first picture really does not show it well, but the car literally wrapped around that tree. The front of the LR had a dead center negative space of the 18" diameter tree. The tree certainly did not move. There was some minor bark damage, but from my sources in Vermont the tree is still healthy and happy. (unlike my LR) I am 6'-3" and had my belt on and can't quite figure out how my head smacked just above the windshield (basically the headliner just below the visor). That force was still able to crack the windshield though. My knees also smashed into the dash and cracked both sides of the dash. I also noticed that the rear bumper was sticking out about an inch or more in the back. But as for any other interior deformation there really was none. Just stuff flying all over......switches, people,etc. There were two other occupants buckled in and they were fine. The truck seemed to have a little list to one side, but there was no damage (exterior) from the front doors back for the most part. I was still able to open my door with a little coaxing. I will try and dig up some more pix of the accident.

By Ron on Tuesday, June 05, 2001 - 01:38 pm: Edit

Jonw:
1) I think this statement is misleading as using an non-airbag ARB on a 96+ is not that big of an issue especially if you pull the fuse offroad. Also early 96s had the 95 style sensors or at least ours does.

Ron

By Blue Gill (Bluegill) on Tuesday, June 05, 2001 - 02:05 pm: Edit

Good to know about the Disco's crash-worthiness. My Disco is Wife and Baby Carrier during the week and my toy on the weekends. Thanks, Garrett.

By John on Tuesday, June 05, 2001 - 02:17 pm: Edit

So how does this discussion group feel about other bumpers from other manufacturers that do not make air bag complient bumpers...such as SG, Trk Outfitters, Rockware, etc......Just looking for healthy opinion....

By Jon Williams (Jonw) on Tuesday, June 05, 2001 - 02:26 pm: Edit

I can see I'm going to have to draw a picture...

IF you don't pull your SRS fuse in a MID-'96 and newer Disco, you risk deploying your airbags unintentionally in mild impacts when using a non-airbag compliant ARB bar.

If you use the same bar on a Disco made up until mid-'96, your airbags are less likely to deploy in any impact, whether you have the damn SRS fuse plugged-in or not.

When you use the airbag-compliant ARB bar on any year model truck with all its fuses in place, everything will function as designed and the event of airbag deployment will depend on the severity of impact.

And, just to make things perfectly clear for everyone, when you pull the SRS fuse, in any year model truck with any ARB brush bar on it, your air bags will not deploy. Period.

By Ron on Tuesday, June 05, 2001 - 02:27 pm: Edit

John,

I like the SG but Kyle's constent bashing has brainwashed me into calling it crap just like the rest of my rover stuff. I have not seen a rockware bumper on a disco but their D90 ones are very nice as is most all of their stuff. No experience with Trek outfitters. I realy like the brownchurch bumpers but then again I am the type of person who thinks galvanized trim looks stylish.

Ron

Seriously though, want I personally want is something relatively inexpensive (SG fails) that improves or does not hinder approach angle (ARB fails) and can fit my choice of winches (Husky). It would be nice if it had a successful use of a dual point mounting system similar to SG but stronger.

By Ron on Tuesday, June 05, 2001 - 02:28 pm: Edit

IF you don't pull your SRS fuse in a MID-'96 and newer Disco, you risk deploying your airbags unintentionally in mild impacts when using a non-airbag compliant ARB bar.

IN theory. Anyone have any experience? I have seen some of these things get pretty hard and not deploy.

By John on Tuesday, June 05, 2001 - 02:37 pm: Edit

I am strickly speaking in terms of all the people that buy bumpers that arent air bag complient....Are you the comsumer ok with making that decision? With all the bumpers out there on the trails that arent in complience...more arent than are....I wonder if everyone is aware, or really dont care. Just looking to see how the consumer feels about the risks...

By Ron on Tuesday, June 05, 2001 - 02:58 pm: Edit

John,

I drive a 41 year old truck w/o a clutch, seatbelts, or effective breaks and which has a metal dash board. I drive this truck without a roof and doors on sideslopes of 45 degrees. I used to drive a truck that you had to "ignite" to start. I am not a good person to ask this question. How does the mom and pop crowd feel?

Ron "Captain Safety"

By Blue Gill (Bluegill) on Tuesday, June 05, 2001 - 03:12 pm: Edit

John - I'm not worried about airbag compliant vs. non-compliant. I'd rather airbags only deploy in the event of a fairly major head-on collision. My wife may smack into a car on-road; if she does, I'm confident airbags will deploy regardless of my bumper system. I am likely to intentionally bump or push cars on-road or, more importantly, bump stuff off-road (and don't want bags deploying my face). I think I'll follow Jon's impatient advice and just yank my fuses if I want to get crazy off-road.

By Blue Gill (Bluegill) on Tuesday, June 05, 2001 - 03:14 pm: Edit

Captain Safety, I bet you keep full gas cans behind the back seats, too and shoot guns and stuff damn capitalist

By Ron on Tuesday, June 05, 2001 - 03:21 pm: Edit

http://www.discoweb.org/alyssa/noah.jpg

The gas cans in question. I have since sold the roof.

Ron

By arb crash test dummy on Tuesday, June 05, 2001 - 03:26 pm: Edit

By Leslie on Tuesday, June 05, 2001 - 03:50 pm: Edit

Ron,

At the moment, I've got 2 gas cans in the back of the Series, but I still have the trop-top on. Being a 'plastic' SIII mine's not as, hmm, barbaric?, as yours.... but who gives a rip??

Oh, FINALLY got the critter running.... pulled the copper cheesecloth of the pickup tube in the gas tank, and used a .243 bore brush and carb-cleaner to remove 30 years of varnish.... it runs now!!!

-L

By Ron on Tuesday, June 05, 2001 - 04:03 pm: Edit

Good to hear it runs, but hey its a series right! Well being an SIII you have belts in that bad boy too. And power brakes. Oh, and a dashboard . . . the luxury. I think at least 50% of series trucks have two gas cans, the more daing mount them infront of the fenders.

Hehehe

Ron

By Leslie on Tuesday, June 05, 2001 - 11:52 pm: Edit

Nope! No seat belts, just the remnants.

Replacing them WAS the first on my to-do list, but now.... first thing is to get the stinkin' locks to work!!!!

Sorry, I got home, and found that my toolbox was nabbed out of the back of the Series while I was at work today. I'm grumbly now. BIG bummer


Think I'm gonna let my lab-chow sleep in it now... heh heh.... ;)


-L

By Blue Gill (Bluegill) on Wednesday, June 06, 2001 - 11:38 am: Edit

Anyone caught stealing tools should be shot on site. I have had more tools stolen than I currently have on my workbench. I hate that. Someone is going to get home with your tools, figure out they're all metric, and then trade them for some crack. Sharpen the teeth on your pup

By Tom Proctor on Wednesday, June 06, 2001 - 12:13 pm: Edit

There is some mis-information here on the inertia sensors, to which most of you have based your ABS deployment theories. I'll try to explain based on my 1996 NAS Disco (imported 4/96).

INERTIA SENSORS
This 96 NAS model has two inertia sensors - one on top of each forward frame rail - behind/above the bumper mounting points. If you look through the ETM you will see schematics and locations for these components, or you can follow the yellow wiring harness within the engine bay. These are the sensors that trigger ABS deployment. They do not *crush*, they simply trigger on impact (inertia).

This system should apply to all pre-96 NAS Disco's as well. I do not know anything about later changes to the Disco inertia sensor(s) location(s), but I do know that the Classiic RR SRS systems relied on an inertia sensor located centrally within the dash or possibly in the center console.

STOCK CRUSH CANS & BUMPERS
In front of the frame rails I had two frame extensions that the stock bumper mounted to - these are the *crush cans*. These only serve to deform on impact and have nothing to do *electronically* with airbag deployment (i.e. the do not trigger the ABS upon crushing). However, they will offer some effect on the ABS trigger point through their intended crumple/energy absorbtion. The Airbag compatible ARB maintains this style of collapsable connection between bumper and frame.

AIRBAG COMPATIBLE ARB BUMPER
This in theory works similarly to the stock configuration, having accordian type crush cans . Although the ARB bumper is considerably stronger than the stock bumper.

NON-AIRBAG ARB BUMPER
The non-airbag ARB mounts solidly to the frame without any purpose-specific crumple mounts. Although the ARB frame mount itself could in fact crumple, it is genearlly thought to be a very strong mounting. ARB's literature even describes this bumper as front end protection that will allow your vehicle to survive (some) impacts and remain in driveable condition.

In closing, the theory that the non-airbag ARB could deploy (SRS) early seems to make the most sense. But a failure to deploy, or delay in deployment caused by either ARB model seems completely unfounded. That said, I have yet to hear/see of any airbag deployments while off-roading in a situation where SRS deployment was uncalled for.


Tom Proctor
96 Disco

By Blue Gill (Bluegill) on Wednesday, June 06, 2001 - 02:13 pm: Edit

good info Tom. The apparent force of an impact could be lessened by crush cans doing their thing (effectively slowing or cushioning the impact), which in turn could affect the triggering of the inertia switches. However, I would think that any difference in the apparent force of a major collision created by crush cans or lack of crush cans would be lost in the overall force of that major collision. In other words, the airbags should deploy in a major collison, whether or not you have airbag or non-aribag ARB.

I wonder if the airbags deployed in that XD that smacked John's smiling tree

By JEEPETR on Wednesday, June 06, 2001 - 02:38 pm: Edit

Well Tom, I guess people either listen better to you, or you are just that much better at expressing the situation than I was, cause it sounds to me like we both said the same damn thing........

~Scott T.
'95 D-90 (JEEPETR)
'96 Discovery (With non-Air Bag ARB)

By Jon Williams (Jonw) on Wednesday, June 06, 2001 - 02:42 pm: Edit

No, the airbags didn't deploy, because Ron pulled my fuse

By charlie on Wednesday, June 06, 2001 - 02:59 pm: Edit

This a very interesting discussion. I wonder how many of the bumpers that are on non LR vehicles are Airbag compliant. I would not want to be hit in by a Ford Expedition with a non Airbag compliant front bumper.

By Tom Proctor on Thursday, June 07, 2001 - 04:48 am: Edit

Scott(JEEPETR),

I didn't mean to offend anyone, but I also didn't want to name names. So, I simply wrote "...*SOME* mis-information here on the inertia sensors, to which *MOST* of you..."

Charlie,

Did you catch that piece on TV the other night showing full-size, off-center, frontal crash testing? That expedition will fold up in front just like the F**d pick-up did...

Tom P.
96 Disco

By ScottTschantz on Thursday, June 07, 2001 - 01:39 pm: Edit

Mike I have a 97 with a non air bag ARB and have had no problems. I have hit the front somewhat hard once. The doors unlocked the fuel pump shut down and the hazards started blinking but now air bag. I really do like it. I hit a deer one time at 40 mph and had no damage to the truck. It paid for itself right there.