really nice overview of ESP. Worth the read...

http://www.keysolutions.com/M-Class.nsf

__________________
...Tracy

'00 ML320 "Casper"
'92 400E "Stella"

Brent,

I’ve always wanted to be a real ski bum, but there was and is always something else ahead of that on list of priorities. So I am mostly a day tripper. But I get in as many days as I can! Congratulations on making the decision. I’m sure you have no regrets, except perhaps for moving away.

Independent estimates of the ML’s angles of attack include 29.5 degree approach, 31 degree departure with stock bumpers. They claim it will climb a 65 percent grade and have photo evidence at (http://www.tufa.de/g-club/mag037.htm) In one of my earlier posts, another tester rated the ML as capable of climbing even a steeper grade. Suffice it to say that climbing is not one of the shortcomings of the ML. I put an entertaining image at the bottom that demonstrates the lateral tilting angle, which is aka the ability of an ML to survive a pot hole. It can also travel through 20” of water without damage to the engine.

In comparison, the G 500 LWB has an approach angle of 36 degrees and departure angle of 27 degrees

Of note is that the original prototype of the ML (the AAV) was 36 and 31, respectively! The platform was originally designed for greater off-road capabilities. I have to guess that MB wanted a more dressed down look and that decision came at the sacrifice of the approach and departure clearances.

Interestingly one of the key differences between the ML and the G are in the ability of the vehicle to go very slowly. The ML 320 has a crawl ratio of 38.59:1 and provides up to an impressive 13500 Nm of force to the wheels while doing so. While the 300GD (manual) has an impressive crawl ratio of 52.79:1 It puts out a comparatively wimpy 5500 Nm of force. (http://www.whnet.com/4x4/specs.html) Gearing is everything and here is one of the key differences between the 2 vehicles.

Next is the all important ground clearance issue. The discussion was based on the vehicles in stock form. The G wins on this one. With a positively reptile-like 8.5” of ground clearance the ML simply can’t distance itself from more than mid sized rocks. A couple of minor modifications would help. By using some obscenely over-sized tires (35”) and raising the front torsion bars to their limit you can get about 11” of ground clearance front and back. Maybe a little more Not a bad gain for a tire change and turning a couple of bolts! Sure big tires will throw the speedometer off and reduce torque but it makes for a small functional difference, and who cares about top speed and mileage estimates when off roading?.

The fuel tank of the ML really isn’t a liability. It is made of the same plastic as is the tank in the G. From what I’ve read, this plastic is akin to “transparent aluminum” as seen in Star Trek. Light, extraordinarily strong, durable and translucent. You don’t hear too many stories about MB fuel tanks rupturing. Plus the illustrations and commentaries I saw indicated that the ML’s fuel tank was able to survive many severe impacts. Still a skid pad is a good thing. I’m sure one could be fabricated without using too much clearance. Perhaps even using this same material the gas tank is made of?

Quoting Brent: “A solid axle is like a big lever. When one side lifts the low side is pressed into the ground as the spring on that side compresses. The ML does not have this feature with its independent suspensions.”

To my reading the construction of the axle has less to do with that than the nature of the drive system. As the drive system is what determines which tire(s) gets the traction. In my last post I referenced a good review for the development of traction control. Here is a summary from that. For the sake of this conversation lets say that a vehicle weighs 4000 lbs and that it has a perfect 50/50 weight distribution. In this case and on level ground each wheel has 1000 lbs of downward force applied to it.

Lets put one of those wheels in a deep pot hole, so that the suspension is all the way out for the one tire.
With a traditional limited slip differential, we all know that the tire that is spinning gets the torque. You go no where.

With locking differential both tires on one axle will turn equally. You continue on.

With 4ETS+ the tire that’s spinning will have the brake applied, and the remainder of the available torque will go to the other wheels. You continue on. BTW, if you have seen a recent commercial for the ML you have observed 4ETS+ in action. In the advertisement one wheel (front left) goes in the air, spinning slightly, it stops as and the ML continues foreword.

A step further, in the case illustrated by the Ml below. One tire in a big hole, another tire in the air.

Again, with limited slip, you go no where.

With lockers, you continue on as the other 2 wheels continue to get torque.

With 4ets+ you continue on as the torque is redirected from the wheels that aren’t receiving traction. In fact being able to increase torque to the wheel(s) with traction can go a long way to actually out perform lockers!

Lets go one more: 3 wheels spinning.

Again, with limited slip, you go no where.

With lockers, you might continue on, if the remaining 1 wheel continues to get some torque.

With 4ets+ you continue on as the torque is redirected from the wheels that aren’t receiving traction to the one that is. This is where the high amount of torque the ML is able to provide to 1 wheel really shines!!!!

With 4 wheels spinning, you get out the winch!

Back to weight distribution. What causes spin is having less traction than needed. The greater the suspension travel, the more traction you get in tippy situations. If one wheel looses contact with the ground, then some of that downward force is applied to the wheel still having traction, providing it’s below the one that’s spinning, of course. This is probably the greatest difference between the ML and the G. The G simply has a lot more wheel travel than the ML.

In fact, it turns out that the comparative Achilles heel of the ML is simply an apparent inability to add some length to the suspension travel. I am still looking into this issue. From my reading thus far, it seems no one has documented how to improve the suspension travel offered by the ML. I can only guess that the ML is still too new to be considered as sculpting material for serious off roading.

A couple of longevity issues: First the ML employs a lot of aluminum. Everyone knows that aluminum is much more prone to metal fatigue than is steel. Unless the ML were used for constant off-road use, I would guess this would not make a difference for well over 100K miles. But it would make a difference, eventually. Second, the front and rear bumpers, rockers and some other finish area on the ML are a light-weight plastic. Obviously these would not last long when off roading.

In summary the “stock” ML obviously will out-perform the G in virtually every regard except in ground clearance, wheel travel, and durability of the underside. While you’d hope that the difference in prices between these two would account for something substantial, you are correct in the cost difference gets you a more capable off-road slow-speed vehicle. Whether the ML can be modified for this task is still under investigation. I’m looking into fairly mild ways to modify the ML. I haven’t found much of use yet, but will report back when & if I do.

Enjoy

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__________________
...Tracy

'00 ML320 "Casper"
'92 400E "Stella"

From LeBenz "In summary the “stock” ML obviously will out-perform the G in virtually every regard except in ground clearance, wheel travel, and durability of the underside."

I've got to find that generally offensive as well as untrue. Here's a couple comparison shots. I put a larger tire on (how big fits on a ML stock?) with stock springs/shocks. I posted a picture of an ML with the largest tires I could find. You tell me which of these two vehicles has better approach, departure!




No mater what numbers you quote, I don't believe you can take your stock ML where I took my stock G. I'll let you use any tire you want that you can fit with no modifications. Iron Chest (Rated 9) and Holy Cross (rated 9, upper section) come to mind. I couldn't even convince MODIFIED vehicles to go with me. Oh, and the price... I paid 12k for mine, what did the ML cost?

You like to talk about it's ability to climb. Big deal, my Subaru could climb a 45 degree flat slab if you gave it hell. That picture I keep seeing off of Harold's site is basicly a really steep road. It's climbing over uneven rocks that measures the worth of a 4x4 in my book. If you ever want to run a real trail, just give me a ring. You can shut us all up right away by just running one of the above trails.

And once again the following (also illustrated above), which for some reason won't appear as a link, so click away...

http://www.peachparts.com/shopforum/attachment.php?postid=167039

Rock and roll!

__________________
...Tracy

'00 ML320 "Casper"
'92 400E "Stella"

I’ve had the great opportunity to chat a little with Wolfgang Henke, legendary individual and Author of Wolfgang’s ML page (http://www.whnet.com/4x4). I have invited him to join our discussion, if he has time and interest. Wolfgang shared with me some minimal things that can be done to raise the ML. First, he says the largest safest wheels he uses are 33” BFGs (285/70 R16) and not 35" tires as stated above. using the 33" BFGs will raise the ML about 2.1 inches over the stock 29” tires. Second is to change torsion bar settings which can be elevated up to 1 to 2 inches (http://www.4x4abc.com/ML320/ml320_torsion.html). This would be done to reduce or eliminate any tire rubbing plus to provide more clearance. He advises caution as severe changes to the torsion bars can result in near term damage to the front driveline. In addition, one should have the front end aligned after raising the torsion bars. Wolfgang said he did not and his ML showed no tire/driveline damage as a consequence.

At Gary Robert’s site (http://www.dragnet.com.au/~groberts), he says one can also install heavy duty (and somewhat longer) rear coil springs. In fact, if you get your ML with the rear tire carrier this is a stock addition. (http://www.dragnet.com.au/~groberts/mlsprings.html ) WRT rear springs, Wolfgang suggest:

”Mercedes springs can be a very tricky business, and they are color coded in many models, including the ML. One has to make sure that a new set of rear springs fits together correctly with the shock absorber and the rubber mounting pads, which in some other models than the ML are used to even out or adjust spring ride height. That's something a good Mercedes mechanic with access to the online system, should be able to check out for you, in Workshop Information Group 32, chassis and suspension.”

A torsion bar adjustment, and different coil springs are both within the area of stock, as there is no non-factory items applied. Oversized tires are literally a bolt-on item but you may want to get different rims to change the offset or just to not risk your factory rims. In addition, Wolfgang claims that the bumpers on at least the ’98 and ’99 models are intended to be inexpensive and replaceable. He should know as he’s replaced 3 sets of them so far!

These minor changes will raise the ML to about 12” of clearance, minimum. As to trail rating, according to this site (http://skidplate4x4.tripod.com/Trail_Ratings.html) these changes would permit the ML to be comfortable on an 8 rated trail (on the 1-10 system) and I could only guess a 3+ or 4 on the comparatively imprecise 1-4+ system)

As you raise a vehicle, there is an increase in tippiness. The stock ML is good (as illustrated above) for 40 degree lateral angles. Wolfgang calculates that the maximum safe lateral angle decreases by about 1 degree for every 2 inches of increased clearance. Even so, he says that by raising the vehicle use a 30 degree lateral as a working maximum even though it should be good for up to 35 degrees. Good idea as when you are way over, even a fairly small rock can gain you an extra 5 degrees angle in a heartbeat!

Koly suggested that by changing the tire sizes you could adversely affect the ML’s traction control system. Actually, by putting in larger tires you will reduce the maximum torque just a little, but that’s about it. As the ML uses computer controlled algorithms to determine slippage and not just simple linier if-then “rules” it wouldn’t really care what size the tires are. Remember this is a fast acting, constantly monitoring intelligent system incorporating 4wd slip control (4ETS+), 4wd yaw control (ESP), 4wd brake assist (BAS), and, of course, 4th generation anti-lock brakes (ABS). Itself, 4ETS+ constantly evaluates (don’t know the interval) for differences in wheel spin while it’s cyber brother, ESP concurrently checks for yaw. If spin is found the system will, of course use the ABS system to brake the wheel(s) spinning, but briefly, and then retest for spin and re-lock if necessary. The 4ETS+ and ESP systems are biased to slow the vehicle down in adverse conditions. If you have 3 wheels with no traction the system will send power to the one that isn’t spinning, but along with re-assessing the other wheels for spin will slow the auto down anyway. Even so, if you want to put it in 2nd and use the 2 pedal technique, you get a 0 slip system that actually is significantly enhanced even beyond what lockers do!

To put the issue in empirical terms, if you were on ice, and the system detected sliding, it would slow you to a stop if necessary to insure safety. As an example, shortly after I got my ML I took it for some test figure 8 in the huge lower parking lot at Crystal on a snowy day. Unless you carry a lot of speed into a turn the 4ETS/ESP system will simply not let the car slide perceptibly, even if you floor the gas pedal, and on a corner ESP will slow the car. If fact, this desire to bring the vehicle to a stop is the well noted problem with ESP! The solution for this type of problem is to turn off ESP. This permits some wheel spin, but does not defeat 4ETS+. When I did more figure 8s with ESP off, I could pretty easily make the ML do pirouettes. It didn’t take much to convince me of how much ESP enhances traction control!

Questions?

Regards

__________________
...Tracy

'00 ML320 "Casper"
'92 400E "Stella"

Howdy Tracy
When can we expect to see pics of your newly raised ML?¿ On the subject of side tip angles, pucker factor starts at about 17°

__________________
Frank X. Morris
17 Kia Niro
08 Jeep Wrangler 4 door unlimited

Frank,

Much as I’d like to, it will probably be no time soon. I have another project that is taking priority, and more to the point, most of my extra $$$. Plus, after spending enough last year on car stuff to make a nice down payment on another house, I promised myself that I wouldn’t do it again. At least this year ;-) Worse, my ML only has about an inch of clearance for getting in and out of my garage. Raising it would make that impossible. And on the same note, getting into the parking garages in the city would become painful if yer ride is a millimeter over 6’ tall.

OTOH, I will need a pickup truck in the near future, and a neighbor about 10 blocks away has a cool 404… Even though it would be noisy and might need some maintenance, it definitely won’t depreciate!

So how much pucker (side angle) can a 404 withstand?









Cheers!

__________________
...Tracy

'00 ML320 "Casper"
'92 400E "Stella"

Howdy Tracy
Too bad about not being able to raise the ML. The side angle on a 404 is 43°. Just to cover all bases a Gwagen is 54°. There are a number of people in your area with Mogs so if you want to see a variety of them I might be able to set you up

__________________
Frank X. Morris
17 Kia Niro
08 Jeep Wrangler 4 door unlimited

Geez, for a tall cruiser I wouldn’t have guessed the mog would stay glued at 43 °. If you would be so kind as to let me know a contact or a few it would be cool to see a gathering of moggers ‘roud here. Thanks for the offer!

__________________
...Tracy

'00 ML320 "Casper"
'92 400E "Stella"

I'M BACK!!! Whew, just tackled a ~2400 mile trip in MBs finest! While out in California we stumbled upon my wifes dream car, the S600. We couldn't ever get our hands on an S55 or 600 where we live, way too rare. We looked at a new 745i BMW, what a hiddeous creation So I finally broke her of BMW and got her into the ultimate Benz, except for the G of course Four days, seven states, my 4.5 yr old twins in the back, the car was spectacular. We used the distronic cruise control system quite a bit, that is a very cool system. I managed to get the attention of a NM trooper, he nailed me for 88 in a 75, $112 fine I had to stop at the dealer in Albuquerque because the car was reporting over filled engine oil. Guess what the loaner was, a 2001 ML320. No offense but that was serious culture shock after two days in the 600.

Glad to see all is well here still. I think something we all must consider regardless of MB model, is how fortunate we are. These are great machines! We all have different needs, so MB offers different models. I happen to like them all in one way or another.

I think the biggest hinderance to lifting the ML is the legnth of the control arms. At some point you just run out of room.

Gotta run more later

__________________
1995 G320
1984 280GE
1971 Unimog 416

Howdy Brent,
Glad to have you back Sorry I missed you when you were in Cal. Maybe next time. Are you going to have a few pics for us?¿

__________________
Frank X. Morris
17 Kia Niro
08 Jeep Wrangler 4 door unlimited

Brent,

Good to have you back! Wow, what a great trip report. And Congratulations on the new toy! That is sooooo cool! Tell us more, and as Frank said, Pix, please.

Re the ML, you are correct (about both culture shock and lifting it). Without going through a lot of headache and expense, it would be far easier to lower a ML than to raise it to more than a foot of ground clearance. Good to hear you got to play with one a little while.

Regards

__________________
...Tracy

'00 ML320 "Casper"
'92 400E "Stella"

Howdy Tracy
Boy , you get it either way you go Raise it and garage and parking structures get you. Lower it and the speed bumps and rocks get you Watch out for those Mogs.....they grow on you

__________________
Frank X. Morris
17 Kia Niro
08 Jeep Wrangler 4 door unlimited

Yesterday I saw the Mog that’s a few blocks from my house and for sale. The owner put a canvas top over the rear! But…………... must……………..… ignore……………..have……………..other……………..….priortiessssssss

Have no fear of turning Casper into a low rider! What a laugh

__________________
...Tracy

'00 ML320 "Casper"
'92 400E "Stella"

I only have one pic of the new car right now. This is at the dealer just as we drove out. Tomorrow is wash day more pics later.

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__________________
1995 G320
1984 280GE
1971 Unimog 416