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Where are the bumper options for the Commander? I saw some really good looking and highly functional bumpers for the Grand Cherokee by ARB, but nothing for the Commander. The bumper even had a provision for a winch. Does anyone know if ARB or any other aftermarket company is working on a bumper for our Jeep?
 

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I called ARB about a month ago, and they said they don't have their Commander bumper finished yet, but they are working on one...
 

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ARB WK bumper on the XK?

Do you think this will work on the XK? Of course you will have to cut the fender flares.

 

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No.
.......
 

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I think what jeep5253 meant to say was.....No, because the WK has some different body lines than the XK. The headlights are slanted upward on the bottom edge compared to the flat edge on the XK. This bumper is designed to follow those lines so it would not work with the style of the XK. The basic frame components under the bumper are similar from the WK to the XK but the body is too different for this to work.
 

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Yeah, that's what I meant.:)
 

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Now we can boast that we have not only a Search Meister, but also a Mind Reader. Way to go Adam.........
 

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Has anyone actually tried to test fit it? If the lines are the problem then perhaps a 1/2- 1 inch drop bracket could be made for the mounting points and piece of metal welded or bolted to the top to create a straight line across. Anyone?
 

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I am not sure about anyone actually doing a test fit but if you talk to forum member El Cid about trying to fit the 4xguard matrix on the XK with the brush bars, the lines are very different. It is not only an issue of the upward slant but the ARB bumper also slants back toward the wheels as it gets farther from the center of the vehicle, the XK is pretty much flat straight across. My guess is that any brackets made to move the bumper out and down would totally compromise the integrity of the bumper and its ability to take an impact or winch from it safely.
 

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I saw an install how-to a while back regarding the ARB/hidden winch system for the WK. It involves cutting out the factory "cross member" and bolting in a new, much more substantial piece. The factory puts in what I would say is a basic C-channel made of formed sheet metal. It's not very strong, but doesn't need to be for the stock application. The piece that ARB uses is basically a box-section aluminum cross member that bolts to the factory formed frame rails. My guess is it has a boatload more shear strength than the spot-welded factory cross member. I think it would be difficult to lower it a bit to allow the WK ARB bumper to drop below the bottom of the headlight "line" of the XK. No doubt it could be done, but the time in fabrication would likely be substantial. Kudos to anyone who tries it. The ARB stuff is quality and it would be nice to have an XK application. Another thing ARB takes in to account on virtually every bumper it makes is the airbag activation. I believe ARB is the only company that addresses airbags and they claim that in a collision the airbags will function per OEM design. I guess the rest of us hope for the best!
 

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Another thing ARB takes in to account on virtually every bumper it makes is the airbag activation. I believe ARB is the only company that addresses airbags and they claim that in a collision the airbags will function per OEM design. I guess the rest of us hope for the best!
Airbag sensors are no longer in the bumper, they are almost all electronic now and are part of the electronics module.
 

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True. I suppose I should clarify my comment - Unless I am mistaken, ARB is the only aftermarket company that certifies that the use of their bumper systems will not adversely effect the function of the factory airbags in a front collision. I don't know how they test for their claim. Jeep (and everybody else) engineers the front crumple zone to react to a certain impact and determines whether the airbags deploy or not, based on the force of the impact. By adding a 100 pound bumper and a 100 pound winch, the way the force of an impact projects into the unibody may no longer be within the parameters the factory has 'calibrated'. Also the way the bumper mounts may change the way the impact transfers into the unibody. So if I have a head-on or near head-on with another vehicle, there's no guarantee the force parameters will be met to deploy the airbags. Likely, they would function properly, but our other-than-ARB systems have not been tested (or certified) to say they will. I guess that's the point I was trying to make.
 

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I emailed ARB. Their response was, "No bloody way mate!" Ok, well they didn't use those EXACT words but that was the gist of it. I also asked about a future bumper for the XK and they said maybe but it was FAR down on the list as the Commander is only popular in the U.S.A.
 

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Also the way the bumper mounts may change the way the impact transfers into the unibody. So if I have a head-on or near head-on with another vehicle, there's no guarantee the force parameters will be met to deploy the airbags. Likely, they would function properly, but our other-than-ARB systems have not been tested (or certified) to say they will. I guess that's the point I was trying to make.
I'm not certain but I think the concern with having a more solid bumper would be premature deployment of the airbags is low speed collisions. You lose any sort of 'cushion' that the plastic bumper creates and the force of the impact is directly transferred to the frame. This would cause the vehicle to decelerate more quickly than OEM system. This greater deceleration would be registered as an impact of greater force, result --> premature detonation of the airbags.

At least that's my hypothesis.
 

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Premature detonation is not good ! :D
 

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I'm not certain but I think the concern with having a more solid bumper would be premature deployment of the airbags is low speed collisions. You lose any sort of 'cushion' that the plastic bumper creates and the force of the impact is directly transferred to the frame. This would cause the vehicle to decelerate more quickly than OEM system. This greater deceleration would be registered as an impact of greater force, result --> premature detonation of the airbags.

At least that's my hypothesis.
Good point. That is entirely possible. Either way, once we've modified the fronts of our XK's with a different bumper system, the factory parameters are likely compromised in one direction or the other. ARB certifies their bumpers are "airbag compliant", whatever that means. Maybe its just a selling point. I have hijacked this thread with comment to an unlikely situation that has ballooned a bit. Though ARB makes terrific stuff, they don't make anything for us and a WK system would, in my opinion, look odd on an XK anyway.
 

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The airbag sensors are supposedly 200g accelerometers according to an associate of mine in the engineering dept of TRW. He said the commander's SRS system is actually a Bosch, but the g parameter should be the about the same. A g-sensor would probably be more sensitive with a stronger front bumper/sub frame because it would transfer force more efficiently as opposed to soaking it up by crumpling, but it would still take quite a whack to trip it. Odds are pretty good if you meet the 200g threshold, you most likely are going to need the airbags to deploy.

Long story short, in the Commander, I wouldn't worry about a bumper messing with the system.
 
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