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Discussion Starter #1
Hi All,
Is there anyone who knows the Center Of Mass point of 406 ?

Or at least I need the following details to calculate it roughly.

1- Front Wheel weight of the truck.
2- Rear Wheel weight of the truck.
3- Side wheels weight of the truck.

Regards
Elbruz.
 

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1988 U1300L RW1 Working gears Dual Tanks AC Rigged for Camping Plus: 91 F250 HD 4x4
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Well, it would first off help to know the purpose and goal of the information. Do you need the Center of Mass (CM) in just the X-Y plane (X = right/ left , and Y = front/ back), or are you looking for 3-axes, meaning Z = up?

I presume you have a truck that you want this data for? In the US, there are many truck scales available. The commercial scales split the scale between axles F/ B, so is easy to get that. Per wheel is a bit trickier. You need a scale that is flush on the pavement, so you can get on the scale diagonally (or maybe offset to one side, then the other) so that only one wheel at a time is on the scale. If the surrounding pavement is much out of level, the weight shifts due to the truck on a slope will render the weights invalid, to some unknown extent.

If you do not yet have a truck, or you cannot access a scale, perhaps one of the Forum members can go out and weigh their vehicle. You would have to elaborate on the specifications for the truck: body type, winch, fuel tanks etc. My SBU would not be a very good comparison, full fuel and water tanks add up to 1400 pounds, for instance.

Now if you need the Z-axis, some of the coach builders for expedition bodies put the rig on a tilting rack and actually measure the angle that causes tip-over, in the final body configuration. Doubt you can come up with this facility, but here is a starting point. Dig through the M-B literature to find the maximum side-slope angle your truck can sustain. Draw the truck to scale, on that degree of side tilt, and run a plumb line up from the outside of the tire contact patch on the road, until it hits the centerline of the truck, the CM must be below that vertical dimension, probably not by much, if that is the manual spec.

Drawing looks like this:

2623452


CM is guaranteed to be within the shaded triangles area, definitely no higher up. All a reasonable approximation of course, but a decent start.

Lee

Think visually, post globally
 

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Discussion Starter #3
Hi.
Thanx for your great advice.
Sure i will try and will share here.

At least i have to calculate the side-slope angle first.

Thanx.
 

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1988 U1300L RW1 Working gears Dual Tanks AC Rigged for Camping Plus: 91 F250 HD 4x4
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At least i have to calculate the side-slope angle first.Thanx.
So I am guessing from this you are working out tipping point for adding an expedition body?
 

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Discussion Starter #5
In fact; My aim is how can i improve the CoG. Because as you will see in the video link, due to 406 has a short wheelbase, it is offroading almost limits. As if it will rollover instantly. So this makes me afraid ( May me the land in the video which that 406 is offroading is very much already prone to rollover for other 4x4s. I dont have that much knowledge to compare a 406 with Hummer,Hilux,Defender etc) and comes to me that it is very very easy to rollover a 406. And i am thinking to add some extra REAR weights to lower the CoG. And most importantly i want to know my limits.


Thanx.
Elbruz.
 

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Unimog Moderator
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There's a great video of a 406 nearly doing an Endo and not rolling over. Unimogs have an insanely low COG due to everything being down low in the Chassis, now the 406's wheelbase is more of a worry than the COG. I've had my 406 at angles that most other 4x4's would roll at and I wasn't near the 406's limits.

 

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1988 U1300L RW1 Working gears Dual Tanks AC Rigged for Camping Plus: 91 F250 HD 4x4
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I have a U1300L, and I definitely am not a "rock crawler", so I am not the best person to weigh in on this.

Perhaps we can get some of the really serious 406 off-roading owners to post up, as to how they handle the tough stuff. Anyone?
 

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Discussion Starter #8
There's a great video of a 406 nearly doing an Endo and not rolling over. Unimogs have an insanely low COG due to everything being down low in the Chassis, now the 406's wheelbase is more of a worry than the COG. I've had my 406 at angles that most other 4x4's would roll at and I wasn't near the 406's limits.

Your words restored my self-confidence. Thanx:)
 

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Took me a while, but I found it:


Now, yes, he has a full cage, and without it the front likely would have crumpled and it might have gone over, but also that's a full vertical sand wall that gave way when he crested and is the same height as the Unimog. So, very stable, but if your doin't $#it like that, cage up anyway.

Original post by DokaTD here: Youtube- wooohooooo

Another thing to keep in mind with the video you posted (great video BTW), is that he has NO weight in the rear of that Unimog. Unimogs flex best when weighted down. All the promotional video's you see of Unimogs on the test track, they are chock full of box weight. If your 406 has the "heavy springs for front mounted implements" as well as the rear heavy springs and helpers you are going to have a tough time offroading with no weight. And again the 406's wheelbase is it's real enemy in comparison to the 416's. 406 is of course an implement carrier, designed for work (as all Unimogs are but the 406 moreso).
 

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Unless you are very experienced offroad guy, your mog will scare the crap out of you before it takes a trail nap. If your really worried get a ROPS .
 

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85' U1300L Holset Turbo VA A/C, 66' Propane 404.1 rock mog, 1975 416 Doka, G500, Volvo C303
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Elbruz, I watched the video you posted and saw nothing wrong. The truck did exactly what it was built to do. At no point was it going to flip over. Having the back tires come up on you is just part of the game especially in a nose heavy truck. One place you could make the truck perform better for you is articulation. If you are not carry a load then you want to consider different springs and ultimately a different shock arrangement. This will make the truck feel more planted.
 

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1976 406 w/ backhoe and dozer blade, a small collection of implements too
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I agree with all that was said above but will note that I leave my logging arch on the back when wheeling (between it and the backhoe mount it weighs about 1,000lbs) as it greatly cuts down on the rear wheel lift. I have tipped my truck forwards enough on a steep down hill trail when dropping off a rock to have touched the bumper on the ground. Scary. Definately, but now that I've done it a few times, it's less so. That being said, I'd just not like to do that at all.

Adding rear weight not only helps in the COG thing but as noted above, it helps in articulation. Since I work my Mog, pulling out the helper springs is not going to happen, and I'm definitely not putting in lighter springs, so more weight is nice.

You'll be impressed with what a 406 can do by an offroad layman. Give it to a real off roader and you get cool videos.
 

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'78 Mog 416.141 DoKa
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All this reminds me of the story Jack Russel once told of the 406 (well, the Case version, anyway) demo driver roaring into a parking lot, standing the 406 on it's nose under braking, climbing out and leaving it that way. Then when he left, he just climbed back in, locked up and drove the back wheels onto the ground and driving off :)
 

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Ok, gotta call BS on this unless the truck only sat for maybe a minute. The forward cylinder would have quickly filled with oil and hydro locked the engine.
 

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Hi All,
Is there anyone who knows the Center Of Mass point of 406 ?

Or at least I need the following details to calculate it roughly.

1- Front Wheel weight of the truck.
2- Rear Wheel weight of the truck.
3- Side wheels weight of the truck.

Regards
Elbruz.
The Case MB4/94 (Unimog 406) was tested at the University of Nebraska's tractor test facility in 1976. As part of the test they measure the center of gravity. Here's a link to the report. You'll find the CG data in the "Chassis" section halfway down the first page on the right.

406 test report
 

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Based on the Nebraska test, with a CG of 34.8" and 12.5-20 tires which are 40", it is a good visual reference that the CG is just below the top of the tires. That makes it easy to see how close you are to rolling over when you're on a side hill - not as close as it feels!
 

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Discussion Starter #17
Hi.

So.. As per test reports, I calculated the points roughtly.
So. It comes to around 48 degree.

If i am wring, please correct me.

Secondly, i found the horizantal point but could not calculate the degree. What is the procedure for that?

Regards.
Elbruz.




2625398




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It is less than 48 degrees. Your measurements don't take into account the body roll allowed by the springs.

BWSwede
 

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Body roll is definitely a factor.

It may be a bit moot though, as I know I can, and have numerous times, taken my truck to 35 degrees, which feels really, really sketchy but I think it's safe. A friend and I stopped when I was at that angle, with about 400# on the bed, and try as we might, he and I could not get it to tip over when pushing on the uphill side. I did this at a spot that if we did tip over, the truck would have only gone another 6 or so inches before hitting and embankment. Unlikely to do any damage so it felt like a safe place to try this out.

It is helpful to note that at 35 degrees you can barely stay in the seat, let alone control the truck so by the time you get that far over, you'll stop anyways.

Things get scary though when you are heeled over to the point it is uncomfortable and then the truck slides, or you have to drop off of something. Then the body roll and momentum can turn things bad.

To date. I've only been around one official roll over and thankfully it was a relatively soft one but also occurred on a hill that was steep downhill and steeply of camber. The front heavy 406 may have made it worse. I nearly flipped my truck over forwards on this particular hill back in the day.
Jessica.jpg
 
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