I'm struggling to figure out a good reason for Jeep's small overlap rollovers

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05/07/2020 at 16:29 • Filed to: None

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Apparently ihs can duplicate the rollovers. Watching the test it just flips onto its side. Watch something else, like a Volvo, run through this test and it's just impact and diversion.


DISCUSSION (42)


Kinja'd!!! CarsofFortLangley - Oppo Forever > Cash Rewards
05/07/2020 at 16:34

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All this anti keep bias. It’s clearly rolling away from danger. It should be MORE safe not less


Kinja'd!!! UserNotFound > Cash Rewards
05/07/2020 at 16:34

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Solid front axle.


Kinja'd!!! facw > Cash Rewards
05/07/2020 at 16:36

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Looking at it a bit more, yeah that’s weird. But then the Jeep is not a normal vehicle.

I am genuinely curious how reproducible these tests are in general (and whether slightly different impact angles would change things). On the small overlap test, so much of the difference between success and failure seems to be based on whether the wheel gets driven into the footwell, and it seems like that could easily change based on slight changes in steering and impact angle. I don’t expect IIHS to crash dozens of every car for rigor (sounds fun though!), but I do wonder if they’ve done a series  on a few models to see how consistent the result are.


Kinja'd!!! If only EssExTee could be so grossly incandescent > Cash Rewards
05/07/2020 at 16:40

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To my untrained eye it looks like the front axle is acting like a lever  and popping the front end diagonally up? It'd be interesting to see what happens with IFS or maybe just more crash structure between the wheel and wall.


Kinja'd!!! ranwhenparked > Cash Rewards
05/07/2020 at 16:42

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It looks like it’s the axle that’s doing it. Another side effect of using a utility truck that’s built for special purpose off-road use as an everyday passenger car substitute. 


Kinja'd!!! The Snowman > Cash Rewards
05/07/2020 at 16:43

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This has been a know flaw for decades some keeps even come with a warning sticker about this "if you can read this roll me over"


Kinja'd!!! CompactLuxuryFan > Cash Rewards
05/07/2020 at 16:47

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I agree it’s probably due to the solid front axle. It makes for a great little rollover lever to catch. As if you put a long beam underneath a car right behind the front wheels and lifted one end of the beam.

I also noticed that the non-crash side front wheel ends up turned all the way into the roll, which is doing absolutely no favors. Hell, this might be enough to roll a Wrangler on its own.

Wrangler:

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Kinja'd!!! Spanfeller is a twat > Cash Rewards
05/07/2020 at 16:48

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I’m inclined to believe that it has to do with the amount of weight over the wheel center line and the front axle. Maybe even the frame(?) I dunno. 


Kinja'd!!! Cash Rewards > facw
05/07/2020 at 16:52

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Oh dear God, do I want to find out. Let me spend a day watching you crash shit. Let me crash 50 of the same car to get an idea of variability. It's got to be so much fun to just wreck these things, you know, for public safety. And science.


Kinja'd!!! Cash Rewards > If only EssExTee could be so grossly incandescent
05/07/2020 at 16:53

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Yeah, but haven't they always had a solid front axel?


Kinja'd!!! Cash Rewards > CarsofFortLangley - Oppo Forever
05/07/2020 at 16:54

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I see no holes in your logic


Kinja'd!!! Cash Rewards > ranwhenparked
05/07/2020 at 16:54

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But haven't they always had the solid front axel?


Kinja'd!!! ranwhenparked > Cash Rewards
05/07/2020 at 16:58

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Yeah, the JK came close to tipping in the small overlap (went up on two wheels), but managed to land. 


Kinja'd!!! gmporschenut also a fan of hondas > Cash Rewards
05/07/2020 at 17:00

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Guess watching on  My phone, is the wheel has so much room to go under the car to start it rotating up. I recall a v90 vid where it was designed to crack to prevent damage to the passenger compartment.


Kinja'd!!! If only EssExTee could be so grossly incandescent > Cash Rewards
05/07/2020 at 17:01

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Yes but there’s just soooo many variables that could be causing this. A fix might be as simple as slightly weaker u-joints so that the hub breaks away instead of the whole axle. Not to mention that the IIHS has only been running this specific test since halfway through the previous generation  of Wrangler.


Kinja'd!!! Gerry197 > Cash Rewards
05/07/2020 at 17:05

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As mentioned, it has a Solid Front Axle, but it always had one, why is it different for this test?

I can only conclude either the testing methodology has changed or the design of the suspension or lower structure has changed that made it rollover easier than previous models.    


Kinja'd!!! camarov6rs > CarsofFortLangley - Oppo Forever
05/07/2020 at 17:07

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Yeah seatbelts are just useless because they keep you in the car. They beat case is for the Jeep to use that tipping momentum to help throw you even farther away from the crash.


Kinja'd!!! Michael > Cash Rewards
05/07/2020 at 17:20

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Looks like it’s riding the frame up and out right here

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Kinja'd!!! Cash Rewards > Gerry197
05/07/2020 at 17:26

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Apparently they ran it again with FCAs methodology and it still rolled, so not that?


Kinja'd!!! HammerheadFistpunch > Cash Rewards
05/07/2020 at 17:27

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I gotcha. The wrangler is a stupid vehicle* in that its track width is much wider than its body width. which means the frame rails are inboard of where they would otherwise be. Which means that when you hit it at the front by the same percentage of overlap as would be suggested by the track width you miss the frame rails and they act like a ramp flipping it over.

*I mean, its not a stupid vehicle...but I’ve hated that since the JK the track witch has gotten huge but the interior volume hasn’t because “gotta have fender flairs!” NO YOU DON’T! PUT THE BODY OVER THE WHEELS!

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Narrow body, wide track

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Notice where the small overlap hits the body and compare it to where the frame rail is. You are hitting on the outside of a frame rail that is flaring out to support the body.


Kinja'd!!! HammerheadFistpunch > Michael
05/07/2020 at 17:29

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Exactly right.  The frame is extra narrow up front for the narrow front clip of the car and the small overlap is putting the rails on the outside of the barrier.  Instead of crumpling, they ride the flair up and over.


Kinja'd!!! Cash Rewards > Michael
05/07/2020 at 17:32

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That could do it


Kinja'd!!! Gone > Cash Rewards
05/07/2020 at 17:33

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Seems like a couple things going on here.
1. The driver’s wheel/tire + outer axle is going under the Jeep, giving it a vertical component. Seems like the main culprit.
2. The tie rod is still connected to the passenger wheel (thanks to the solid axle), steering into the hit as the axle is ripped from it’s mount on the driver side. Bad.
3. During the initial hit, the DS rear suspension is extended (lift) as the DS front wheel is pulled under the Jeep, and is trying to rotate the weight to the right front suspension, but now the right front suspension goes full compression (maybe the pass coil spring comes off it’s mount) the rear cg is rapidly gaining height over the front.
4. Now things get ugly - it’s like endo-ing a bike but you’ve tucked your front wheel simultaneously. The Jeep is trying to rotate to the front and the right at the same time, as the passenger front wheel turns into a pivot point in quick succession. I think if the front wheel goes right it doesn’t roll.

The Ranger also has some weird crash dynamics. The small overlap on the passenger side is sketchy! Seems like the soft springs allow the front to tuck the nose. The end result is the passenger A pillar gets completely obliterated by the crash barrier. Yikes!

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Kinja'd!!! WasGTIthenGTOthenNOVAnowbacktoGTI > CarsofFortLangley - Oppo Forever
05/07/2020 at 17:33

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Better to be thrown clear of the vehicle that’s throwing itself clear.


Kinja'd!!! Gerry197 > Cash Rewards
05/07/2020 at 17:33

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I didn’t mean the difference between the FCA vs IIHS, I mean how IIHS tested from this year to the last time it was tested and it didn’t roll over.  Their methods or procedures could have been different.  

Though if I had to choose, since this is an all new design, I figure something in the lower structure/suspension helped it roll over earlier than the previous design.


Kinja'd!!! Cash Rewards > HammerheadFistpunch
05/07/2020 at 17:34

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I think this is it. Michael posted somewhere a pic of the frame and it matches exactly what you’re saying.

BUT MAH FENDER FLARES!


Kinja'd!!! ranwhenparked > HammerheadFistpunch
05/07/2020 at 18:11

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That’s probably it, compare it to the JK:

It doesn’t tip, but isn’t totally stable looking, and the frames are very similar between the two generations. Could be some other variables that make the difference in causing it to roll  further beyond the point of recovery.


Kinja'd!!! UserNotFound > UserNotFound
05/07/2020 at 18:32

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Upon reading some other replies (including HammerHeadFistPunch’s) it makes more sense that it would be the narrow front frame. The front tire being smacked back and then hitting that taper on the frame seems to be enough to wedge it up in to a roll.


Kinja'd!!! CRider > HammerheadFistpunch
05/07/2020 at 18:34

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While the outboard wheel design does have some flaws, it gives stability (hard to sell that after this, but it does) to an otherwise tippy platform and you know you’d rather bang up plastic fender flares than body panels wh i le off road.


Kinja'd!!! HammerheadFistpunch > CRider
05/07/2020 at 18:49

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Nuts to that, it’ s already wider AND shorter than a 4runner an its not like those are rolling over every corner. The JLU is 2.5 wider in track than a JKU, which is 4 inches wider than a TJ.  Reminder that the 4runner which is basically the same size as the JLU has nearly 40% more interior volume.


Kinja'd!!! CRider > HammerheadFistpunch
05/07/2020 at 18:56

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How often do you see 4Runners with 37" or bigger tires? Very rarely. The 4Runner is a much more moderate off road truck than Jeeps are. It's p erfectly capable, but if you get into tight spots the JL will feel narrower than its track width indicates.  


Kinja'd!!! SPAMBot - Horse Doctor > Cash Rewards
05/07/2020 at 18:59

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It's a jeep thing, you wouldn't understand.


Kinja'd!!! HammerheadFistpunch > ranwhenparked
05/07/2020 at 19:03

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The JL is 2.5 inches wider in the track. Frame rails stay put, overlap position changes to be less favorable.


Kinja'd!!! HammerheadFistpunch > CRider
05/07/2020 at 19:06

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Look at all that interior space!

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I mean...64.4 inches wide and its got Corolla hatch interior volume.  Square that boy up and put the width to use!

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Kinja'd!!! CRider > HammerheadFistpunch
05/07/2020 at 19:15

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That looks bizarre. How much more engine bay do you need? The 6.4 already fits in there.


Kinja'd!!! HammerheadFistpunch > CRider
05/07/2020 at 20:00

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It looks bizarre because you are used to the other thing... And it’s a 5 minute Photoshop. This new hood   is less wide than a midsize truck h ood.


Kinja'd!!! CRider > HammerheadFistpunch
05/07/2020 at 20:06

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Going back to the 4Runner, they both rate as marginal in the small overlap test, the Jeep because it rolled over and the Toyota because it actually crumpled the occupant compartment in the test. So while the JL may roll over, the 4runner driver will probably fare worse.

The 4Runner is shown at the end here. 


Kinja'd!!! jeepoftheseus > HammerheadFistpunch
05/07/2020 at 20:10

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Why put gear inside where no one can see it? It’s better to strap it to the roof/sides/back/hood so everyone can see the gear right? LOOK AT ALL OF MY GEAR!! Just kidding, I have a TJ, nothing fits inside except.... wait, no nothing fits in there except for a passenger, some tools and a weekends worth of camping supplies . If you bring the dog then something has to go in the hitch basket.


Kinja'd!!! DipodomysDeserti > HammerheadFistpunch
05/07/2020 at 20:31

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I’m still dumfounded as to  why they didn’t make the cargo area large enough for a cooler.


Kinja'd!!! DipodomysDeserti > HammerheadFistpunch
05/07/2020 at 20:34

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So what you’re saying is, it’s a Jeep thing.


Kinja'd!!! Victorinoo > Cash Rewards
05/07/2020 at 20:37

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The front axle attachment arms to the body. They act as a catapult as they rotate down to accommodate the front axle moving backwards on impact.


Kinja'd!!! Old-Busted-Hotness > Cash Rewards
05/07/2020 at 20:44

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There’s nothing in front of the wheel, so the spinning wheel hits the barrier and tries to roll up & over it. Just what you want it to do when off-roading.

The naked wheel obviously can’t give enough traction to climb a vertical wall, but when you add momentum, it’s easy to see why it flips.