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Roll Cage Test Results.

Discussion in 'Early CJ5 and CJ6 Tech' started by Norcal69, May 11, 2020.

  1. May 23, 2020
    Bigdaddy13

    Bigdaddy13 Member 2020 Sponsor

    So.Cal
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    I’m not sure what you mean? Looking back at the OP’s photo’s, the cage WAS tied into the dash-board(a good idea that i am putting in my cage also) but still displayed exactly the kind of deformation /energy absorption that ITLKSEZ mentions.

    I‘m taking ITLKSEZ’s point to mean that outboarding the supports would have prevented or minimized the A-pillar’s movement because rather than simply relying material strength (which it is), it would also rely on mechanical strength by being tied into a node at the B-pillar, and therefore the rest of the cage “box”.

    What we’re talking about with the a-pillar, from my point of view, is basically a cantilever from the point at which the a-pillar attaches to the dash. It recieved a point load at the end of the cantilever and absorbed the momentum of the crash by deforming. Norcal69 has stated, tho, that this was an un-finished cage, and, as such, did pretty well all things considered.
     
    Last edited: May 23, 2020
  2. May 26, 2020
    46ODDFIRE

    46ODDFIRE Member

    Newport News, VA
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    All this has me recalling some youthful indiscretions, shuddering, and counting my blessings.
     
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  3. Jun 4, 2020
    Norcal69

    Norcal69 Out of the box thinker 2020 Sponsor 2019 Sponsor

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    I was hoping to update this thread with pics of the new cage.... and additional gussets (beyond what the fabricator did) that I planned to add...... but it ended up at the powder coat shop before I was able to work on it. :shrug:
    Will post pics when its back I guess..... but Steve likely wont let me take a grinder to his fresh powder coat..... :ninja:
     
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  4. Jun 29, 2020
    Norcal69

    Norcal69 Out of the box thinker 2020 Sponsor 2019 Sponsor

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    I was finally able to get a pic of Steve's new cage gussets. They are not exactly what I had in mind......:censored: but I was not the one who relayed the information to the cage fabricator. Unfortunately the cage got whisked away to powder coat before I even saw it.....
    The gussets will be much better than no gussets..........

    [​IMG]
     
  5. Jul 6, 2020 at 2:16 AM
    teletech

    teletech Member

    Santa Cruz, CA
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    wreck.JPG I'll just throw in that when I rolled at low freeway speed, the bar that saved my life was a very simple single-hoop bar simply attached to the body. I really don't feel like I need any more bar. I'm not that tall a guy and I would plan on retrofitting a shoulder belt. Otherwise changing tires is my main safety upgrade. I will say I bruised a couple knuckles which may have been as the windshield frame came down close to the steering wheel so a cage might have saved me that pain.
     
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  6. Jul 6, 2020 at 7:38 AM
    colojeepguy

    colojeepguy Colorado Springs 2019 Sponsor

    At the foot of...
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    Damm, looks like that was a nice Jeep too :(
    My CJ looked similar when I got it...the PO rolled it at highway speed and walked away with minor injuries. Like you, it just had the standard hoop rollbar.
     
  7. Jul 6, 2020 at 10:08 AM
    timgr

    timgr Jeepin' Nerd 2020 Sponsor 2019 Sponsor

    Medford Mass USA
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    IMO you were quite lucky that the windshield did not come further into the passenger space. Didn't even break the glass. Looking at that, it makes me believe even more that you need the forward bar. I rolled my first CJ-6 and was badly injured by the windshield hitting my face. At the least, the front bar will keep the windshield and pavement (and steel cab) out away from you.
     
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  8. Jul 6, 2020 at 10:10 AM
    Norcal69

    Norcal69 Out of the box thinker 2020 Sponsor 2019 Sponsor

    Northern California
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    X2
     
  9. Jul 6, 2020 at 10:13 AM
    teletech

    teletech Member

    Santa Cruz, CA
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    It came back into a straight line between the rollbar and the very smashed sheetmetal. There was no way for it to come further back under the circumstances since it was a roll onto flat pavement. Now, if I were offroad and there were big rocks around I could easily have been in worse trouble.
     
  10. Jul 6, 2020 at 10:27 AM
    Bigdaddy13

    Bigdaddy13 Member 2020 Sponsor

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    Those look fine to me? :shrug:

     
  11. Jul 6, 2020 at 10:28 AM
    Buildflycrash

    Buildflycrash Member 2020 Sponsor

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    You may want to adjust the headlights down a bit as well. :lol:
     
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  12. Jul 6, 2020 at 10:42 AM
    timgr

    timgr Jeepin' Nerd 2020 Sponsor 2019 Sponsor

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    Suspect that any other roll angle would have smashed the corner of the cowl and pushed the windshield further into the passenger space. Looks like any impact went straight into the front, nose down. Lack of damage to the cowl is noteworthy.
     
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  13. Jul 6, 2020 at 10:52 AM
    timgr

    timgr Jeepin' Nerd 2020 Sponsor 2019 Sponsor

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    This is the only pic I have of my wrecked CJ-6. It's a scan from a Polaroid, so the original quality was not great.

    [​IMG]

    Note the bent windshield frame and the angle of the dash from left to right. This Jeep went over on the front left corner.
     
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  14. Jul 6, 2020 at 11:07 AM
    Bigdaddy13

    Bigdaddy13 Member 2020 Sponsor

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    Jeez! that some significant damage. Agreed, I've seen enough rolls on body mounted bars, to believe that solid body mounts with backup plates of some sort are a good measure against the bar separating and maintaining the passenger bubble.

     
  15. Jul 7, 2020 at 2:03 AM
    teletech

    teletech Member

    Santa Cruz, CA
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    Note the bent bumper on the front, it went over on the front corner and side then ended upside down. The front of the cowl came back about 10", the steering column bent downward and formed a bit of a V in the dash. Sure, it could have been worse but it was bad enough that I'd consider it representative of a bad roll. Worse than most I've seen in the wrecking yards. If I had been over 6' or had a taller seat bottom I'd have been in real trouble. Similarly a curb or boulder would have been a serious health risk. As it was the biggest hazard was oncoming traffic.

    Actually, although the roll isn't really something I recall Based on the damage to both sides and front, the skid marks, and the angle of the road, I have reason to believe it might have gone over first on the passenger side and then flipped over onto the front driver side before rocking back to turtle.
    I also would like to get some better gas caps, the feeling of that much fuel running down my left arm was... disquieting. Luckily all the hot parts of the motor were above me.

    Oh, and kids, wear your seatbelts and also change them out from time to time, or at least the webbing. The freshly installed Simpson made being upside-down comparatively comfortable and unbuckled easily.

    I didn't mean in any way to hijack this thread, just saying a single bar happened to work for me in a particular situation that isn't that unusual.

    I think a full cage is a good call for rock-crawling and support people trying to be safe but also don't want anybody thinking a CJ5 is ever going to actually be safe. Years ago I knew a guy who did auto insurance for a living and he told me the CJ5 had the worst accident record of anything he'd ever looked up.
     
    Last edited: Jul 7, 2020 at 3:00 AM
  16. Jul 7, 2020 at 2:16 AM
    teletech

    teletech Member

    Santa Cruz, CA
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    I wound up replacing the front clip and W/S frame, manged to save the tub eventually. Matching the weird fleet Imron my uncle had it painted in the late 70s is proving a challenge and holding up progress.

    I'd almost rather have a better body mounts and weaker frame to body coupling so the two parts could go their separate ways. I'll keep the light sheetmeatal, thanks. The other part, well I'll come back and get that later. The risk of having two parts is you have that other bit come at you later so it's all a tradeoff. Speaking of light, I think the jeep being pretty light really helped me out here.

    In this case the body to bar junction shows no signs of separation but it does have long and heavy connections to the body.
     

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    Last edited: Jul 7, 2020 at 2:31 AM
  17. Jul 7, 2020 at 2:34 AM
    teletech

    teletech Member

    Santa Cruz, CA
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    Um, no glass in that picture. The W/S frame is a taco and the glass is in a bag in the back of the Jeep.
     
  18. Jul 7, 2020 at 9:00 AM
    Norcal69

    Norcal69 Out of the box thinker 2020 Sponsor 2019 Sponsor

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    I wanted them about twice as long with an arc in the opposite direction. I intended to then weld a piece of 1/8" plate across the top with a couple dimples in it.
     
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  19. Jul 7, 2020 at 9:46 AM
    PeteL

    PeteL Member 2020 Sponsor 2019 Sponsor

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    This discussion reminds me of the old story about WWII bombers.

    An intensive study was done of flak damage on returning bombers, and the boffins made plans to up-armor those specific areas of the aircraft.

    Seemed very logical until someone pointed out that the planes hit in those locations were the ones that survived.

    This thread is inevitably biased in that it lacks input from the Jeepers whose cages totally failed to protect them.
     
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  20. Jul 7, 2020 at 10:38 AM
    Norcal69

    Norcal69 Out of the box thinker 2020 Sponsor 2019 Sponsor

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    Unfortunately many jeepers that realized their cage did nothing for them didn't survive the crash. :( Much like the bombers... the pilots weren't around to tell the engineers where they got hit.
     

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