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