"We've compared the M class with the G-Wagen...
 

on the off-road test track. The M class runs faster."

http://www.autonews.com/article.cms?articleId=20941&a=a&bt=jeep+g-wagen

Very good article dating to 1997 on the development of the ML. Fairly technical & explains a lot of the suspension & driveline choices employed in the ML and the technological advances that permit the ML to employ a mix of simpler hardware yet produce “superior” results.

Worth the read

Enjoy!

Well Tracy,

I'm not sure how to respond. I know you think this, and the Paris-Dakar post, is helping to make your point regarding the MLs off-road prowess. I don't want to start another flame war, it will only be deleted anyway. I will try to illustrate some distinctions.

I think first we need to preface off-roading, which has many definitions. Paris-Dakar and high speed rallies are one type of off-roading(desert running). Trucks like the ML and the Hummer do well in these situations because of the independant suspension. They are more stable at speed, as referenced in the article. Then of course, in my neck of the woods, the locals consider racing through a huge mud puddle as off-roading. This requires big power and bigger tires, I doubt anybody here is considering this. The type of off-roading I prefer would be best defined as trail riding with some rock crawling, though rock crawling can get rather extreme too. To avoid further confusion, trail riding and rock crawling are what I am referring to when I say "off-roading".

So for my type of off-road use being "faster" through an off-road course is of no use to me, or most recreational off-roaders. The course used would also be in question. I have built a small off-road playground for my trucks. It is designed to challenge them, and scare first time passengers(which it does). The ML would simply not make it over this course, it would be hung up on the door sills within the first 20ft. This little course of mine also pales in comparison to the type of trails I like to run in my G. So while the ML may be capable enough for some, it does not fit my needs. I would also like to reference back to Harold Peitschmans site. He owns an ML320 and a couple Gwagens. His "home track" is the Rubicon trail, possibly the toughest passable road in the US. To get the ML through he removed the bumper caps, carried wooden ramps, and brought a Gwagen along to pull the ML over tough sections. I find this very demonstrative of the MLs shortcomings in tough off-road conditions, and the reason I consider the ML primarily a road car.

I'm not sure why such great offense was taken in previous threads. Certainly the ML is a capable machine. It just does not have the capabilities I need. While many Gwagen and ML owners will never go off-road, those that do know what works and what doesn't. In the real world, the MLs off-road capabilities are not sufficient to tackle most trails. This is in spite of technology and the best efforts of the engineers. It is clearly stated in the article that on-road manners were important. I also think the article is a bit of marketing, I think the truth has been stretched.

To further make my point I would like to see an ML in Moab. This is a premier off-road venue in the US. The MLs limits would be found rather quickly. The trails rated 3 - 4+(scale 1 - 4+) would stop the ML. I have led a trail ride on one of Moabs 4+ trails. We ran three stock Gwagens on this trail with no damage. It is a testament to a dedicated design. The ML simply is not that dedicated. Its true stregnths lie elsewhere.

If you can get over my rude demenor, pack up the ML and head on down for our next Gwagen outing. There is even a G500 in Seattle that you could caravan down with. You can try out your ML, and I am really not trying to be insulting here, and could ride along in a G through the really nasty stuff. It is truely a good time. I did not sense any snobbery, even from the guys that dropped $150k each for the G500s that showed up.

Your point about the ML being a capable machine is duly noted. Unfortunately I will never believe it is the off-roader you seem to want to make it out to be. Correct me if my impression is incorrect, but you seem to be trying to correlate the MLs abilities with those of the Gwagen. I assure you that in the conditions I operate my G there is no comparison. I would be more than happy to demonstrate its capabilities in the real world, as opposed to in a magazine article. ;)

Brent

Howdy Lebenz
Good Reading!¡ Gives a good insite into the design philosophy. Much has been, let's say, "enthusiasticly" discussed about the mechanical prowess so I will let that rest. The comment in the article about the small percentage of owners that go off-road.(That pertains to all SUV owners) It is a mission in my life to get people to get out and enjoy the backroads in the world. If not in their own vehicles at least ride with someone that is willing to take riders. When my Mog is done being restored and I get a Gwagen I will invite anyone that wants to come along.(If anyone wants to ride in my Jeep YJ thats ok too). At the present time my work schedule makes it hard to get together with other people. But that is changing soon. So I hope to see some of the forum members on the trail.

One other thing I found interesting in that article was the comparison to the Jeep and Explorer. I suspect that part of the off-road course demonstrates sidehill capabilities. This is a big strength of the Gwagen. It wouldn't surprise me in the least if those Germans designed the same capability into the ML. There was definately more though put into the MLs design than the Ford or Jeep. I suspect that where the ML or G would be very stable the Exploder would roll, Jeeps are also notoriously tippy machines.

People always ask if the G is real tippy. A natural question as the G is one of the tallest vehicles on the road and is narrower than an ML. The low center of gravity allows seriously gut tightening manuvers. I took a fellow G owner as a passenger in Moab. He was a first timer to real off-roading. The first day his questions revolved around the theme "you aren't really going to try that are you???". By the end of the second day he was egging me on to climb or drop off every obstacle in sight. I have to agree with you Frank, it is pretty rewarding to annoint a newbie. I try to do the same as you, last winter I even took my mother-in-law, THAT was interesting!

Brent
Done Rambling :p

Brent and Frank, Thanks for the comments! Unfortunately I just started a project that has me swimming up to my ears. I will be busy through the weekend but not before my day off tomorrow for what I hope will be another epic day on the slopes (we’ve gotten about 4’ of cold smoke this week. Tuesday was outta this world)!

I want to pursue this topic as I’m finding that the ML actually has most of it’s more rugged capabilities hidden from plain sight. I found a cool article yesterday that showed that at least 80 members of the ML design team came from the G team. For some reason the source I found won’t let me get at the articles again (autonews.com)

I also found a link saying that the ML was conceived as a replacement for the G wagon. There are a lot of articles covering this area. Here is one:

http://www.autonews.com/article.cms?articleId=37151&a=a&bt=ml

The following is an excerpt from that article: M class connection?

The Mercedes M class, introduced in September 1997, was conceived as a replacement for the Gelaendewagen, more suitable for U.S. tastes than the clunky original.

Paul Halata, CEO of Mercedes-Benz USA, says he doesn't expect to see the present G class more than another two to 2½ years. A redesigned M class is not due until around 2005, but a replacement could come sooner if Mercedes speeds up its eight-year cycle. Mercedes isn't saying whether a new M class and a new G class would share development.

The leather-lined 2002 G500 has a new interior and high-tech features such as electronically controlled traction control, yaw control and satellite navigation.

Piarulli says the target audience for the G class is younger and wealthier than M-class customers - age 44 for the G500 compared with 50 for the ML500, and a median income of $353,000 for the G500 compared with $182,000 for the ML.


Until I can spend more time on this, here are a couple of links and pix denoting some background information:

In my link in the previous note a Gerhard Fritz was referenced. Dr Fritz is the head of G, M, and V class development. Here’s a little something about him and the ML:

http://www.mbusi.com/pr/worldcar.html

And about it’s tippyness; there is an article here by our Webmaster, Lee Scheeler that makes reference to http://www.peachparts.com/mbcot.htm
(Note you will need to scroll down a ways)

And here are some pix of the ML in Moab
http://communities.msn.com/MLAdventures/pictures

And about the merger of the ML & G wagon, as well as the expected lifespan of the current G see

http://www.whnet.com/4x4/mlg.html

Enjoy! I will probably not be able to make much ground but will sneak a few minutes here and there to add more info, and more importantly to address Brent’s nicely illustrated points. In the end I think you will find that the differences between the ML and the G are more in comparatively small and in the case of the ML correctable degrees rather than in paradigms.

And I would like to add that Brent is correct that the ML is designed for road use. But only in trivial ways. However, add a little bigger tires and remove the definitely-not for off road plastic bumper covers and all that changes.


About the ML’s climbing ability, here’s a pix from Pietschmann’s site. He rates it as able to climb a 45 degree hill. Cool, no?

To quote Phillip Roth: “Now we may to begin.” Yes?

I've done that climb in your pic, it feels steeper than it looks even in that pic.

Congrats on the snowfall, it has been bleak around here. Winter just isn't much fun without the white stuff around.

Time for a "healthy" debate?
 

I am very pleased to see that we can continue this little debate regarding our chosen mounts.:D

The MLG issue is still debatable.I don't think it is clear even to MB what exactly they are going to do. To bring the G here for only a few years does not make much sense. The underground rumour is that MB paid $30 million to buy the rights to sell the G here. I know that sounds strange but, Europa Intl held legal distribution rights to the G in this country. So MB had a serious outlay to do this. I think they are testing the waters right now. They will build the G regardless for the various militaries. I think if the G sells well they would be inclined to continue updating the original rather than replace it. I suspect they are also gauging whether or not there is room for two MB SUVs.

It was neat to see some ML pics in Moab. You gave me just what I asked for you little devil. ;) Of course the trails pictured are rather tame. To take on the more difficult trails you will need more than larger tires on the ML. I might note that we had a G500 make it through a 4+ trail on the stock 65 series 18" tires. That surprised me, AT tires are still king in the rough though. The ML has a few strikes against it for off-road use. The bumpers, obviously. Then there is the limited suspension travel. This means more tipping and less traction. The traction control system I think is a liability off-road. When you get in a tight spot, teetering on two boulders, I want my mechanical lockers. The ETS system needs to detect wheelspin to activate. The slightest slip in a scenario like this means you come away with custom sheetmetal.Another issue is the low sill hieght to facilitate egress. This means a poor breakover angle. Which in plain english means you will high center much easier than in the G.

Certainly the ML CAN go off-road. I still maintain that the G is far more at home in the dirt, at least for my style of off-roading. It is something you would probably have to experience firsthand to believe. I really think that is the only way to make a convincing case. Sure the ML is very rugged, better than its competitors in true MB fashion. But it wont go where my G will, even substantially modified. In that case, a few simple mods to the G and it is widely accepted as the finest off-road machine on the planet. You've got a tough row to hoe on this one Tracy:eek: I look forward to continuing this saga, and I am very pleased to see we can do it in a civil, fun, fashion.

Brent

Know I am going to start something.

The title of the finest off-road vehical should go to the "World Cup Cross-Country Champions" and that is the ML430.

While the G may perform certain off activities better than the ML. The ML has clearly proven it is more superior to the G in over-all cross country championship. Because off roading does not just include rock climbing, it included things like dirt road, open grass fields, mud fields, sand dunes.

To me clearing going fast on dirt roads, open grass fields, muds fields, and sand dunes the ML's with its ESP, ETS, and independent suspension is superior. You are going to try to blash through a mud field, soft sand if you can. Who is going to have time slow down and lock in your differencial(s). Let ETS do it.

The point is that the G may be better on certain types of cross country terriagn, but the ML is superior on more other cross country terriagns and that is why the are the Over all "Cross-Country Champions"

blau

p.s. what hell happen to spell check!!

In my opinion it depends on the circumstances to which vehicle is best. In some situations, the ML will outperform a G due to it's lighter weight, I have in mind higher speed running such a dunes and open trail with no or little outcroppings, such as rocks or stumps. The way MB kept everything up between the frame rails is especially impressive. This is a good reason to have 4 wheel independent suspension on a vehicle like this, so the diff can be up above the frame rails.
In other cases where the going is slow and steep, such as rock climbing and bad terrain, the G is the way to go. It's important to remember on the 2002 versions in the US that it normally is running with ETS and ESP, until an axle is locked.
Gilly

blau,

That isn't starting anything. I purposely gave an explaination defining my type of use. If yours includes high speed rally type running I think the ML would be the faster choice. I hesitate to say better because I am confident that over the long haul the G is going to prove to be more durable.

Gilly alluded to another similarity, the first being a low center of gravity, both are designed to keep the vitals safely tucked inside the safety of the frame. This is contrary to most SUVs that drive around with all kinds of stuff hanging below the frame. Jeep is terrible for this, I don't know how they keep exhaust on those things.

One flaw in the independant suspension is that upon a serious compression of the suspension both wheels go up and the diff becomes the low spot that strikes the rock or stump. With a solid axle the diff moves with the wheels keeping it from harm.

Locking a diff on the G does not require slowing or stopping, just a push of a button. Beyond the ESP and ETS locking a diff also disables the ABS.

G-Man:
If you think that statement through about the independent suspension flaw, it really doesn't make sense. How could a wheel rebound up high enough to make the differential strike an object? The bottom of the tire would need to rebound up so high that it was higher than the bottom of the diff, that can't happen, certainly not on an ML anyways, not with the diff being up between the frame rails. The half shaft would hit the frame rail before that ever came close to happening.
The real beuty of the independent suspension is that it allows go much more ground clearance for driving over an obstacle, such as large rocks that are in your path that can't be driven around. With the solid axle the bottom of your differential will always be closer to the ground, unless you use a scheme such as the Humvee's geared hubs, or some other way to effectively raise the differential in relation to the axle shafts.
Gilly

I think a trip to the MBUSA website would be appropriate right about now. They have a great animation of what I describe. I didn't get the link but go to G500 through the models pulldown. Then open up the features and go to off road performance. Navigate to the ground clearance demo.

You are somewhat correct in you assesment. On flat ground there is no way to stuff the diff into the ground. In places where the ground is peppered with obstacles it is a different story, as demonstrated by MBUSA.

The other issue I have pertains to this statement "With the solid axle the bottom of your differential will always be closer to the ground" What is the measurement to the bottom of the diff on an ML? The G has pretty impressive clearance. The other thing is that the diff housing on the ML is very likely aluminum (correct me if I am wrong) while the diff in a G is housed in a VERY heavy duty steel section. It is designed to withstand multiple serious hits without damage. I think the ML is listed as having ~8" of ground clearance.The problem is that 8" is all you get, it is the min and max clearance. My G, on stock sized tires, has 10" under the diff and 12-14" minimum under the remainder of the axle. I noticed on 4x4now.com that it is pointed out that the gas tank on the ML creates a problem off-road. One picture shows a ton of damage to the, admittedly tough, Gwagen style tank. Putting a skid plate on it would only diminish the already slim clearance.

All of the above serve to demonstrtae compromises made by MB to make the ML more carlike. There are unfortunately at the expense of its off-road capabilities. ;)

MBUSA clearance specs
 

Funny, I went to MBUSA and they list the ML at 8.7" min clearance and the G500 at 8.3". That is strange because I measured mine in the garage and it is an honest 10" under the lowest point. Maybe that is with flat tires:p

Blau,

You would only need to lock the differentials if 4ETS can't get you through, and frankly, by the time you figure that out, you're probably stuck. Knowing when to lock the differentials is part of reading the terrain. It's an added capability available only in the Gwagen.

On the whole, I think driver ability is the most important when it comes to offroading. This applies to rock crawling, river fording, and blasting through sand dunes. All the toughness in the world cannot save you from falling off the back of a sand dune... a good spotter will.

Kuan

Kuan,

You're sorrect on dirver ability. It applies to all motorsports. I have seen a 4 cyl 944 fend off a 10 cyl Viper on the racetrack. It was all the driver.

On the contrary, when we had a G gathering in Moab we had one novice in a G500. With a little coaching he was able to go places in a stock G that would require serious modification of another vehicle. The spotting was important but, no amount of spotting would get an ML up the Z turn on the Moab Rim trail. You need the proper tool sometimes.

Howdy All,
Now all we have to do is get together and go for a ride. Then after the ride sit around the camp fire and lie about how great we did :) Now that sounds like an idea to me :)

I feel I have to chime in here

As for the pix of the ML running Moab trails, I won't believe it is as capable as some think until I see pictures of an ML on Hell's Revenge, Moab Rim, Golden Spike, Poison Spider, the Golden Crack or any other 4 or 4+ rated trail.

If Rallye Raids and high-speed desert-dune running is what you prefer, then Mitsubishi appears to be the spot to look, as they claimed this year's top EIGHT finishers in the Paris Dakar in the car/4wd category. That's the top EIGHT spots. In a row. I'm not trying to be coy, but where did the ML's place (I honestly couldn't find any - mainly because the main dakar site is difficult to navigate and I couldn't find much in the way of information or stats of any relevance beyond the top 10 in each category) - and I would actually like to know.

Being realistic, there are far more trails in the U.S. that offer slow, technical-driving through woods, over rocks, in mud, across moguls, and over hills where you are actually in low range. The opportunity to drive flat out at high-speed on dunes and dirt roads is not near as commonplace for your average back-country explorer, or even your avid trail-rider. Unless you live near the Mojave or the Baja, there really aren't a lot of places like that. It's also usually illegal to drive that fast on dirt roads, and quite dangerous on either if someone happens to be coming the other way. That's why the Paris Dakar is billed "the world's most dangerous race."

Coming from the midwest to the deserts of AZ, I've found all kinds of trails along the way where the order of the day is the more than appropriate motto "drive as slow as possible but as fast as necessary" and you not only need low range, but you wouldn't consider running the trail without it.

Since that other thread of ours was erased, and I had made comments regarding ETS and it's ilk, I have a comment about adding bigger tires to an ML as suggested below (these comments are by no means personal, just point-of-fact):

As G-man (I think) pointed out, ETS requires wheel-spin to activate. On the slick-rock of Moab, this can be, in some cases, deadly. Imagine climbing that 45 degree hill. (Question - was it 45 degrees, or a grade of 45%? There is a vast difference between the two). One wheel starts to slip - just enough to slightly turn the car off of perpendicular to the climb. At this point, depending on the steepness of the hill, that can be the end. Just a little slide off-center (imagine Lion's Back), with wheels already spinning, and you cannot change the laws of gravity and momentum. boom - game over.

The other point here is the idea of adding bigger tires to an ML (or any vehicle with any type of ETS, and for that matter, ABS). In the old (deleted) thread, I pointed out that you have no control over when the ETS will kick in. Will it be 30 feet up the hill where it looks like you might lose traction? Will it be after you start to slide backwards 2 feet? Will any wheels be in the air at that point? You don't know, and you can only predict, because the ETS will kick in when the computer program's algorithm tells it to.

Now you add bigger tires. Your speedometer is now off. Your odometer is now off. Your ABS is now adversely affected. I cannot imagine taking the risk of trusting my ETS to function correctly after I've now PURPOSELY thrown off the entire equation it was based upon (which was designed and calibrated SPECIFICALLY for the MFGs suggested and supplied tire choice, and, most likely, PSI).

When it comes to safety and trail-riding, I believe you should do everything in your power to protect not only yourselves, but those with and around you.

Good discussion going this time - I'm enjoying the lack of name-calling! :-)

Seems like the official Paris-Dakar site is not meant for us who don't know how to use a GPS! :D Actually, the M-Class finished 2-3-4 in their class, 38-41-42 or something like that overall. They participated in the unmodified category. The Mitsubishis which won all competed in the super modified.

ETS kicks in when the difference between tires is 3mph, 1.2mph at low range. Big tires won't affect the ABS, the ABS sensor only detects lockup and releases the piston when that happens. It's conditions which affect wheel lockup, not tire size. As far as traction is concerned, I don't see why ETS is any different from locked differentials. If you have no traction on one tire then you have no traction. The locked differentials allow one tire to keep spinning, ETS brakes the spinning tire. Either way you have traction on only one side so I don't see much difference. Brent care to explain why locked diffs are more desirable when fording water?

Hmm... Kuan

I feel like I am being set up on the question about water crossings:eek: Why would locked diffs be better? I'm not sure what you are getting at. My biggest water crossings were in an old Bronco2. I had water up over the hood on that thing many times. It had no lockers or any thing fancier than a good set of tires. Sometimes it would stall just shy of getting out. This was in a very powerful mountain stream. I personally wouldn't bother with more than the center lock and moderate speed. If it looked like it was going to take more than that I doubt I would drive into it. So I don't think you need either the locker or ETS for water crossings you are likely to encounter on regularly used trails.

The "spinning tire" issue needs to be addressed. With a diff lock one tire does not spin necessarily. As Koly pointed out and I stated at the outset we are talking about low speed manuvers here. With one wheel in the air the locker turns both wheels at the same speed. If you are in this situation spinning a wheel should be the furthest thing from your mind. Gently easing to the next obstacle would be more like it. So the airborne tire will turn the same speed as the tire with traction. This is a very important point that is being passed over by the ML group. Wheelspin is a BAD thing. It means a tire has lost traction and can send you off course, right now. If you have run the 4 - 4+ trails in Moab you would know that a little spin can mean an instant rollover. The positive, driver controlled lockers, are easy to predict. With ETS you wait for the computer to react. I'm sure it is quick, and maybe even somewhat predictable with some experience, but it still requires a pretty good slip to activate. The point trying to be made is that, just a little slip can be very dangerous. Selecting a locker just before you engage the obstacle avoids the slip, clean, quiet, safe, and less damaging to the surface than spinning a tire.

This is not meant to be inflammatory but, I think some of this needs to be experienced. Some of the places I have taken a Gwagen look totally impassable. Words are not sufficient to describe these situations. Lockers are like cheating. I have had to help lifted Jeeps on big tires through before. These jaded folks are amazed by the Gs abilities. I'm sure the ML is a great truck but we are really comparing apples to oranges. There is just no way the ML can compete off-road with the Gwagen, not if I can pick the road.

Nope nope, my mistake. For some reason I thought it was better to lock your diffs before you start crossing water. I think I see it, I haven't experienced it yet. OK I see what you're saying. In a sense it's better safe than sorry, better safe than VERY sorry.

Kuan

Thanks for the info. So, the class that the M's competed in was what? Stock? I only pay attention to the three main classes - Trucks, 4wd cars, and motorcycles, and don't know too much about any of the other classes... Any url's you can point me to?

Some problems here:

Larger tires most definitely affect ABS. The computer that controls the ABS measures wheel speed (larger tires=slower rotation per distance traveled) and compares this to the speed it thinks the vehicle is going to determine when to use and not use the ABS. This, in turn, will affect the ETS system.

For example - w/stock tires you are travelling at 50mph and 3200 rpms. With larger tires, when you are ACTUALLY traveling at 50 mph (remember the speedo will still show 50mph=3200RPM, but in actuality at 3200 RPM you'll be doing a speed higher than 50mph, due to the larger tires) your engine revs may now only be 2900 RPM. So, you'll be farther down the engine's power and torque curve. THEN ADD TO THAT the fact that with a larger radius tire, a given torque at the axle shaft (produced by the motor at a given RPM) will produce less reactive force at the road, due to the fact that the road now has
a "longer lever" to work through in the larger tire radius (thanks Dave ;-)

The ETS will also be affected by the reduced reactive force.

As far as comparing ETS to locking differentials, there is no comparison. Here's a very simplified breakdown of how each works in one scenario:

Scenario - climbing a hill with moguls deep enough to cause extreme articulation - enough so that your front passenger side (PS) wheel and rear driver side (DS) wheel are in the air.

ETS - Without ETS, the two wheels that are hanging in the air will spin, as that is the path of least resistance for the differential. You will be stuck. Then, ETS kicks in and says "whoa! we've got wheel spin. Let's apply the brakes to those wheels that are spinning, and that will help distribute some of this unused power." The ABS braking system then activates and starts braking, which starts to distribute some of the power to the wheels with traction. The problem with this is that each wheel is not getting equal power, as some of that power is lost in the transfer via the braking and spinning.

The other problem with this is that you have already been stopped by the obstacle and have to get the hanging wheels spinning in order to activate the ETS.

LOCKERS - by equally distributing power between all four wheels at all times guarantees that any wheel with ground contact will be pushing the vehicle. You won't stop when those two wheels are airborne. It won't take wheel spin to activate the lockers. Your momentum and traction will not be lost.

Unless you have witnessed both on the same obstacle in person, you really can't get a picture of the difference. And the difference is truly amazing.

Koly,

Let's make sure we're on the same page here. ETS is the traction control which is supposed to mimic locking and limited slip diffs. ABS is antilock brakes right? ETS and ABS do not work together. ABS works only when you stand on the brakes. When the tires lockup, the brakes release. So the only difference being that for the same amount of time that the brakes release in between lockups, the larger tire will roll a little bit more. That's the only difference larger tires will make with the ABS.

I hope this link works:

http://www.dakar.com/2002/us/classementsSpecif.oft?service=DRaceServer&RaceYear=2002&RaceType=DAK&StandingType=SCR_A&StageNumber= 1610&Group=T1&Class=T1.1&Category=AUTO

Kuan

In defense of ETS, it is capable of directing 100% of engine torque to a single wheel. I don't think there is a bunch of wasted power when the brakes are used to direct torque. I read in one of Tracy's links, that even after prolonged use the brakes did not overheat. So for what it is, it is very well done.

I think the potential for lost momentum is a concern. I think that more than anything I am really curious to see how well the ML would do. I don't mean that I want to try and rip the bumpers off, but I would like to see ETS in action on a real trail.

Are there any ML clubs that take them out for trail rides?

Okay G, when it thaws out maybe I'll ask some of our M-friends if they wanna come up there? What say you?

Kuan

We are indeed talking about the same thing. ETS (Electronic Traction Control) and ABS (Anti-Lock Braking System) are intertwined. I do not believe that ETS is supposed to 'mimic' a locking differential. It certainly doesn't, as it allows wheels to spin and applies brakes, thusly, not distributing all the power evenly across axles (power is still being sent to the wheel w/the brakes applied - some of the power is therefore lost). A locking differential dispurses equal power all the way around. I could see ETS as a mimic for a limited slip differential, but not a locker.

As to how they are connected:
When ABS senses locked brakes, it releases and re-applies the brakes to keep you from sliding. When ETS senses wheel spin, it basically co-opts the ABS and uses it to apply and release the brakes. They both use the same system of pumps, pads, and computers to activate/deactivate the brakes. Both use the same (or similar) computer algorithm to know when to activate. Changing one of the major factors in that equation (overall wheel size) will definitely have an effect. To state that the only difference a larger tire will have on ABS is that it will roll a bit further is a bit non-chalant. Longer stopping distances and an incorrect application of the ABS's spec'd functionality is the result. And if you're standing on the brakes to try to stop, it usually means it's an emergency. With bigger tires, (regardless of ABS), it's going to take a longer distance to stop. To me, that is an extremely important change.

A small change in tire size (say, going from the stock 29" ML size tires to a 30 or even 31) will not be as noticeable as something more dramatic. It will still have an adverse affect, but, especially on day-to-day driving, not as evident as on the trail, where you WILL notice it. However, many trails I run require tire sizes of 33" or more, if for ground clearance only. With a 13% change in tire size, (besides the obvious fact that your low range is now no longer very low and you wouldn't be able to make many of those climbs), I would be scared to entrust my life to components spec'd for a drastically different setup.

Again, I'm w/G-man here. The loss of momentum, the beginning of wheel spin, and the potential for danger is too much for my comfort level. The only real way to understand is to see the two side-by-side on the same obstacles. The difference will astound you.

Question for G-Man:I was not aware of any ETS that was able to apply 100% of the engine torque to a single wheel. I would think that would be the easiest way to break an axle... Power still needs to be sent to the spinning wheels in order to apply the brake to them so the differential kicks in and takes the path of least resistance, or at least dispurses the power. Maybe I am misunderstanding something, but that is how I have seen all ETS systems function. However, if the engineers at MB came up with some other method, it wouldn't surprise me.

As to brakes not overheating - how long are the brakes applied to the spinning wheel? Nowhere near long enough to overheat them. I don't think the brakes are used nearly as hard in an ETS situation for a few seconds when compared to stop-and-go traffic braking.

Kuan - thanks for the Dakar link! But from that page, it appears that only 5 competitors in the 'scratch' field actually completed the event? Is that true? That site is really quite terrible. Perhaps if I spoke french it might make more sense?

On the ETS. Koly I think you covered it. With the brake applied (airborne wheel locked) 100% of the torque flows out the other way. But I see your point, if the wheel with traction turns, the computer must allow the airborne wheel to turn within 1.2 mph of the other. Obviously you don't get 100% in that case. Advertising hype? Works in theory? I'm not sure. On the axle breaking, MB has the technology to limit torque in the driveline. On the Europa G500s I know that they limit engine torque in low range, with the front locker engaged, as to not break anything. I suspect a similar tact was used on the ML. I know my new Chevy pick-up limits torque in low range too.

Kuan, Thaw??? Geez I was just out on the track today with some fresh snow(love those lockers). I had a guy from Allison Transmissions looking at my Chebby truck today. He was a motorhead too and was talking about his sons CJ-5 and such. Just before lunch I took him on the course in the Gwagen. He hung on a lot and commented that he didn't figure his sons Jeep had any business on that track :D

I'd love to see a couple MLs show up. Don't play it up too much, it is just a dirt pile in a corn field:rolleyes: We could fill in the holes a little and see some good articulation from the MLs. It would be a perfect way to see the ETS at work. There are also a couple pretty good side hills that lean you over. I'd be up for it anytime!

Torque limits ?'s
 

I've not heard of this torque limiting - I am more than intrigued as to how a system like this would work - any URL's your info you can point me to or further descriptions? I'd like to know more.

Sidenote:
Where is Verndale? it's quite funny that three of the active posters here all have Minnesota ties - I'm originally from MN, and lived mainly in DT Minneapolis for quite a while before moving to AZ.

Well, that is a tough one.I know about the torque limiting on the G from Jason @ Europa. I don't think I have seen it in print. I know it is used on my chevy because I had it thwart my efforts once. 300hp truck with 520 lb/ft of torque that can't spin its tires on loose dirt, hmmmm where did the power go. The forum dedicated to those trucks revealed that engine torque is limited in low range because of the torque multiplication. I suspect that finding out about the chevy would be easier than finding similar G material.

I know it exists, I have seen it work, I am not crazy;) I'm not sure how excessive torque is determined or controlled, but now that you mention it, it sounds like a subject I may follow up on.

Beautiful Verndale MN, located right in the center of the state. It is between Staples and Wadena on Hwy 10. I am about 30 miles due west of Brainerd. It may not make your map as the pop. is under 500. I actually live in Staples and work in Verndale. We moved here about 7 years ago from NE Mpls, off Broadway between University and Central. It is much quieter here:o

I think you're missing the simplicity of ETS-4. The front and rear differentials are "open" design, in old days we old hot-rodders just called them "single-spin differentials" as is the transfer case, if you don't have a problem visualizing a transfer case as a kind of differential. With the tranfer case, if you have no problem realizing that the G-Wagon transfer case "locks", then you should have no problem visualizing the ML tranfer case as "open".
OK, so the left front wheel is in the air, or on glare ice. The tire loses traction and begins spinning. The ETS control unit "sees" this and using the pump in the control unit, stops the spin. The power, due to the "open" design of the front diff, transfers to the other 3 wheels, not just the other front, it is all shared. Actually, a small amount of power will go to the wheel that was spinning, as the ETS is constantly analyzing if the spinning tire now has traction, if you've seen this demo'd, you will have noticed the tire that was spinning "chattering" for lack of a better word, as the ETS tests for traction.
To continue, if the other front tire is now on glare ice (guess they can't both be in the air! ((well they CAN, you know what I mean)) the wheel speed will be seen by the ETS control module, and the process continues, the brakes are also applied to the other fron wheel, and because of the open design of the transfer case, the power is now going to just the rear axle, except for the small amount to the front as the traction to the front tires is monitored. And if traction is further lost at one of the rear wheels, then that brake will also be applied and power transferred to the wheel with traction. I am unsure what happens when your traction drops on that wheel, I believe the wheels will probably all spin because the ETS computer now doesn't know what good traction looks like anymore, so to speak.
The good thing about the ETS on the ML is that the mechanics of it are pretty simple and light, it's the electronics that do all the dirty work. I don't think how ETS-4 works can be categorized as imitating either a locker or a limited slip differential, it's really a unique thing.
Gilly

ETS explaination (and torque limiting)
 

Good points Gilly...

In my explanation, I neglected to point out exactly how and where the power transfers to from the spinning wheel... for simplicity I described it the way I did... your ice analogy is a good one to really show off and help explain ETS.

G-man, if you poke around any more regarding toque limiting, I'd be curious to hear what you find out. Just an interesting subject, I think - trying to figure out how those clever engineers manage to dissipate that energy somewhere is pretty cool :) . And after your location spotting of verndale, I have a good idea right where you're located - lots of good trails up in that neck of the woods. I had a girlfriend who's family lived in Brainerd, and when we'd go visit, I'd usually find a way to sneak out and run a trail ;)

BTW (completely unrelated) - have you ever gone to the Ojibwe SCCA Rally?

I don't think it is a matter of dissapating the energy. I think it is a clever use of electronics to somehow calculate torque output and limit power production with electronic throttles. This is a little OT but does apply to the Merc vehicles too so here goes. I learned a lot from an Allison Transmission tech today. We looked at percent throttle opening, trans input and output speeds etc. The engine control computer also knows when you set the cruise control, it knows when you ask for power via throttle opening, it knows what gear you are in, 4wd or not, it knows how fast you are going it knows the tempand humidity outside, lots of stuff, in addition to various sensor monitoring. It is amazing what we could look at real time on the road with a laptop. Point is, with all of these parameters being monitored it shouldn't be too hard to limit power. On the G500 for example, the computer will see you select low range, it will see you select diff locks, it can then monitor the throttle opening and calculate availible torque based on rpm, road speed, throttle postion etc. and could easily reduce the throttle opening to remain within programmed parameters. Unlocking the front diff kicks it out of the limiting program and away you go unaware that anything happened. That is my understanding of how the systems work. One key advance that makes this all possible is the death of mechanical throttle linkages. Kind of scary really, but it allows cool features like the torque limiting.

I haven't followed the Rally scene much. THAT is some wild racing, I am really glad it seems to be having a comeback in the US. I should get out and watch but, you know the story, just not enough days in the week to do all of the stuff I want to do.

The amount of power the engine is capable of producing isn't altered, but the engine control module does control the throttle itself. This has been the case ever since the demise of CIS-E injection back in the early to mid 90's, depending on the engine.
"4WD" is not a possility on an ETS-4 vehicle, as ETS-4 is an AWD system. I don't believe the engine controller on an ETS-4 even knows when it's put into low range.
Mainly, the engine control unit will alter the throttle setting based on info from the ETS-4 control unit, which is only acting upon info from the 4 wheel speed sensors. It also of course alters the throttle opening to control idle, to accelerate/decelerate in response to drivers commands, and also cruise control inputs, there is no seperate cruise control module anymore.
Gilly

G,

Speaking of rallying, they're gonna be running in Garrison on Lake Mille Lacs on 2/2-3, 2/9/10 and 3/2-3, at Thunder Bay on
2/23-24. I guess word is that they have to hit the track because of lack of snow and ice. Anyone here know what it takes to get like a Novice license? Man, be nice to go run with the dogs :)

Kuan

I might try for the one in March. I am going to be gone next week to sunny So. Cal. so I would miss the first couple dates. Thunder Bay is too far and too cold for me.

I am not sure what is required for a license. The SCCA sets up a booth at the Mpls auto show every year though. I am sure they could tell you. I am going for a competition license starting with Porsche Club Racing. Since I have already started, most of time having one type of racing license helps you to get one with a different sanctioning body.

I have seen some of the cars being trailered. Looks like you could do it on a pretty low budget. The cars I saw were old RX-7s and a Dodge Omni. I still think tearing around in the woods would be really intense. With a cheap car and good safety equip. I bet it would be a blast.

Gilly, What I meant is, that by modulating the throttle, the computer reduces the amount of power produced. I did not mean to imply that the computer in any way changes the potential output of the engine.

Hi guys. Skiing Friday saw 2’ (feet) of freshies on top of another 4 feet of snow in the last 5 days. I was lucky enough to be one of the first down a little breath-taker called Powder Bowl. Got stomach-deep snow on a steeeeeep grade. Ohhhhh baby. Anyone wants, I have a nice early season pix of this spectacular hill. The drive to the resort and back was a delight with complete snow & ice covered roadway for about 60 of the 80 miles. Brent if you aren’t doing anything we currently have the best snow of the far west.

If you root around long enough you can find from what linage the ML evolved, so to speak. As pointed out before the ML was designed in the mid ‘90s as an AAV and intended to be the next generation of the G wagon. The MB “family” had and still does have the G and I think engineering and/or marketing were looking to entice some new meat, so to speak. Mercedes being Mercedes (even in Alabama) wanted to advance the state of the art in SUV engineering and utilize modern approaches along with innovative combinations of equipment and manage the hardware with technological advances (read that, computers). They did and are continuing to do a nice job. Really it’s odd that a vehicle this feature rich in off-road abilities is mostly hidden. While in it’s inception the ML was more styled for off road use.
(http://www.4x4abc.com/aav/ ), during its development and marketing, upscale soccer moms (and the occasional ski bum) are the targets. In true Mercedes form, they’ve appealed to both. In its off-road prowess the only real shortcomings are the tradeoffs made for lower step in height and wheel travel to reduce body lean. Notice that on the new MLs they have made the front and aft bumpers considerably shorter, to increase the approach and departure angles (and no doubt due to people *****ing about the bumpers being scraped off).

For the moment, since the 4ets system is under current discussion, I’ll attempt to pick up there. Gilly well covered the system, except that it has continued to evolve in MY 02 to 4ETS+ I don’t think it’s been mentioned but 4ETS+ refers to 4 wheel Electronic Traction System +. The 4ETS uses the ABS sensors as data collection sensors and it also employs microcomputers to sample the data collected by the ABS sensors. The computers use a series of algorithms to quickly apply differing amounts of braking force for differing circumstances. 4ETS also uses the brakes to effect change in the rotational speed of any one or multiple wheels as necessary. 4ETS is extremely responsive and is designed to do a multitude of tasks. As Gilly pointed, out the system employs open transfer cases which provide a great deal of adaptability for quickly directing torque. In addition to this combination of systems, the ML also employs another system called ESP. ESP provides directional stability. It too works by quick and selective activation of the brakes to counter the effects of yaw. These systems all work together and concurrently.

I mentioned above that with the ’02 there is a “+” added to 4ETS. This is a brake load booster that empowers even quicker response times (rated at 500 ms.) In the case of 4ETS the system manipulates the drive system of everything from the ML 320 to the up to the ///AMG ML 55. And it can do it in about 1/100 of the amount of time it would take you or me to do it!

“This allows 4ETS to apply the brakes to spinning wheels even sooner and to make optimum use of the drive power. The system releases brake pressure in response to the driving speed, wheel acceleration and accelerator pedal position.” (see http://www.whnet.com/4x4/4etsplus.html for a nice discussion of 4ETS and 4ETS+ and MB themselves mention ETS almost in passing at http://www.mercedes-benz.com/e/innovation/glossary/lex_begriff21.htm and for a brief but detailed history of traction control see http://www.whnet.com/4x4/abs.html#ETS )

In addition to the previous paragraph, the 4ETS+ offers a so-called “Two foot mode.” Here is an excerpt: a benefit when it comes to moving off on steep gradients. In "low-range" mode the system also works if the driver pushes down the accelerator and brake pedals simultaneously to ensure that the M-class does not roll back when moving off slowly. The previous 4ETS system was not activated in such conditions.”

Further there are a couple of other goodies integrated into the system used for other eventualities: “On the MBUSI off road course during my factory delivery, the driver demonstrated the anti-rollback feature of 4ETS+. With the transfer case in LO range, and the Touchshift in first gear, he drove nearly to the top of a steep hill, then took his foot off the accelerator. The truck actually rolled backward all the way down the hill and then the engine shut down automatically. He explained that as a safety feature. Next, he made the same maneuver in 2nd gear and the truck would use the brakes to hold any position on the hill. He said there was a special circuit in 4ETS+ for anti-rollback and hill decent that only works in 2nd gear.”

Pretty cool! In summary, 4ets+ is fast, and all but replaces the capabilities previously found in locking differentials. As an aside, that the G for MY 02 also uses the 4ETS system but not the + version. However the G also gets locking differentials or “lockers….”

That’s all for the moment. Will cover ground clearance and performance specs next

BTW did someone say Moab?

http://communities.msn.com/MLAdventures/moabwhiterimtrail.msnw

Tracy, I am openly envious of your ski situation. I was a ski bum for a year at Colorados A-Basin. I skied everyday from Nov 15 until June 23 when they closed that year. Now I am stuck in the flatlands, at least temporarily.

Glad to have you back. Now to continue on. I agree that the ETS is a good system. Sounds like the new version is even better. I still do not consider it as good as a reliable mechanical locker system. Even if the ETS can mimic the lockers function the ML still has some strikes against it. Ground clearance is a big issue. Even up sizing the tires will not be enough for most situations. I wonder how large you can go? Would a 265/75-16 fit? That is the size on my G right now. I would like to fit 285/75-16s next time. The 285 is 33"s tall. This is generally accepted as the minimum size for serious wheeling. The G's supernatural capabilities exempt it from that requirement in most cases. How about the fuel tank issue? Is there a skid plate that can be fitted? The pics I have seen show it to be very vulnerable. One more point here. 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 independant suspensions. I may not be real clear on this but, there is an advantage traction wise just because of the axle configuration. I will find the link and post it.

Now to settle my end I will offer the following challenge. See my web page. The movie is about 2.5MB so if you have a dial up it will take a few minutes to load. Kuan, get your buddies together! If you guys can find an ML to take the challenge and succeed, not only will I pay off on the wager but I will publicly concede on this forum. http://homepage.mac.com/brentholm

Wellllll. If there is going to be a ML vs G showdown, count me in!

http://www.wehenrys.com/gwagen/soft3t.jpg
http://www.wehenrys.com/gwagen/framp5t.jpg

For those interested, this picture was when my G was BONE STOCK except the tires. I just tossed on some 265/85/16's and went out and ran some of the hardest trails in Colorado. I had some clearance and suspension issues (which I'm fixing) but I was still able to complete every challenge. I would like to see an ML even approach this ledge, but the G scampered right up. I can think of very few vehicles that could have done this without modifications, I know my old LR Defender 90 couldn't!

http://www.wehenrys.com/gwagen/china1t.jpg

Howdy GollyGwagen,
Welcome to the Forum. I noticed in your sig. line "Q" is that what you want us to call you?¿
Lets not call it a "showdown" but a "fact finding mission". On another thread we got a little overly enthusiastic about the difference in vehicles so we are trying to keep from becoming tooooo "in the face". Since we are spread all over the place it's a little tough to get together but a couple of the guys live within reasonable distance so they are going to do some fact finding and report back the results.And then we can inflict flesh wounds to the heart :) Oh by the way nice pics.

I am new here, and certainly don't want to start on the wrong foot, but there are 4 basic elements that decide whether or not you will make it over an obstacal. Power, clearance, approach/departure, and traction. While I believe the ML probably has plenty of power and (with the right tires) grip, I would have to say that there is an issue with clearance and angles. Those bumpers are huge!

I tell you what, I do a lot of wheeling in Colorado, and would love to take an ML out wheeling. I mean it, not a 'drag them to a place where they will do damage' kind of thing. I have a bunch of trails near the house that range from really easy to moderately challenging. We could run through all of those to get our feet wet, and keep moving on to more difficult trails. It would be interesting to do a comparison and I would love to have other MB's on the trail. If anyone would like to go wheeling, but don't know how or where in Colorado, drop me a line and we'll go out and have a great time. Mettberry gulch would be a fantastic starting trail, and a stock Explorer can make it through. Then there is Longwater gulch (some deep water), and Hackett (the one real challenge... Hackett Rock)

After those we can move out to Chinaman's Gulch, then Wheeler Lake, Iron Chest, Holy Cross, and finally the Independance Trail bypass, Freedom.

I think that is a fantasic listing of trails that rance from 4 to 9 (on a 1-10 scale) and nothing is a quantum leap in dificulty. I've done them all and know them well. I even saw an ML in the area of the Gulches, but I couldn't convince him to join our group and run the trails.

I would guess if we laid out the pro's and con's of each vehicle, we would find that each vehicle has it's stong areas. Rally racing is to me a place where I would be no match for the ML, in any flavor. But rock crawling is an area where my G excels, and I have out perofmed many vehciles who area well suited to it. I would really love to go wheeling with ML owners, so please let me know if you live in the area and would like to try the addictive sport or wheeling. You'll love it!

I think Q made another good point. While you may be able to make the ML perform OK off-road it will require some modification. That is part of the beauty of the G, in totally stock form it will embarrass anything else stock. It will also leave behind most modified, purpose built off-roaders. In addition to these skills it is also a quiet luxurious cruiser. I have comfortably run mine, for hours, across desert highways at 90mph. If you so choose the G can be lifted a couple inches and fitted with larger tires. Now it is a match for anything out there. As an added bonus it is designed to withstand many years of this type of use. In any other vehicle it would be considered abuse, well except maybe its siblings the Pinzgauer and Unimog.

The ML is certainly a fine machine. It was designed with serious durability and longevity in mind. What is being missed here is how seriously overbuilt the Gwagen is. We have one G club member that owns a 1980 280GE with over 250k miles on the clock. I also met the previous owner who used it off-road for over a decade. It still sees plenty of use, daily and for play. The truck is in spectacular condidtion and is functionally perfect with little more than routine service. Do you honestly believe that the ML was designed and built to this standard? Remember that the G has been hand built in Austria, in the same factory, by many of the same people, for over twenty years now. This truck is built the old fashioned way. Brake lines are hand bent over a jig. Frames are welded by hand by experienced artisans. I am sure that computer controlled robots are capable of repeatable quality manufacture. I still prefer a competant human brain controlling the work directly.

Out on the highway technology can be a wonderful thing. When you are miles from anything on a boulder strewn trail I will take mechanical simplicity anyday. I view things like ETS as a liability. I think a large issue here is the needs and intended use by the owner. If rock crawling is not on your agenda, the premium for the G is not justifiable. You will pay a penalty in ride comfort, handling, and acceleration. If you do intend to USE the G, there is no finer choice.

Check this link for a description of the MLs capabilities. The pic at the bottom made me laugh, sorry but that is really pathetic. http://www.4x4abc.com/DV/01/report3.html ;)

Howdy All
It makes me think that maybe that would be something you might want to have some momentum and hit it. But you should be able to just roll right over it. We have seen some pics of the ML in action and the more I see and read the less inclined I am to believe what anyone says. Just let me drive one to see if it fits my style of driving. I am still going after a Gwagen.

I'm with frank on this. That rock in the picture. You could drive over it even with a regular car even if the ML has no off road ability it should have not difficulty.

I bet I could drive over it with my 87 xr4ti or the honda accord. I know because before my ML. I use my honda accord to go camping and sometimes there are trails that has bigger obstical than that.

blau

Fella's,

I have to say I'm very impressed with the tone of this thread, we have all just got along...

G-Man, I'm the proud receipient of a California Offroad Commission 4x4 certification. A one day course with several hours of lecture on trail navigation. This was followed by an afternoon on the course with instructors/spotters helping each of us through each hazard; mud pit, water crossing, hillside navigation, sand, and boulders.

The best part of all this was that it was all a group of ten ML owners and a couple with an ML55. Needless to say we all bonded during the day putting our trucks through their paces.
The instructor has seen most "SUV's" try his course and he was impressed with the ML's capabilities!

While I might not compare the offroad prowess of my ML with a Hummer, or GWagen for that matter. I ran out and got brush guards for the front and tail lights just in case ;)

Remember guys, these are just sibling rivalries, we're still driving the safeset most capable vehicles in their class!

Howdy ML Dude,
Glad you got out and tested your ML. You live right down the road from me (less than 2 hours away) I am about to get off the weekend work ordeal and ready to invite people to come up to El Mirage to the OHV park for some off-roading fun. We have trails for most any taste. So if you or anyone else don't mind 4 wheeling with someone who has a Jeep lets get together sometime.I hope to have a Gwagen by May and my Unimog done by October. So I might need one of you ML people along to pull me out of a sticky situation:)

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

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

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! :eek:

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

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!

http://www.wehenrys.com\gwagen\topless21.JPG
http://www.4x4abc.com/images/ML_265_frontlift9.jpeg

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.

http://www.tufa.de/g-club/images/NEU_BWH.JPG

http://www.tufa.de/g-club/images/NEU_BWV.JPG

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!

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

http://www.whnet.com/4x4/pix/ml_on_rocks.jpg