[JoeE46M3]

I know we talked about tow ratings in previous posts..but I have a question.

How come the Unibody w164 can tow almost 2300 pounds more than our W163's? Body on frame is tougher, power is close to the same, braking is close..

I am going to swap springs with Eibach (Mabey H&R) and install new Bilstein struts..this should help with my already great towing of my 3400 lb boat...but we are looking at a 24 Baja Outlaw Go fast..and I am just curious why all the experts say.."tow with a body on frame" and all these new Unibody (X5, W164 ect) have much higher tow ratings than out trusted W163's..

Any comments?

 

[bruntoj]

I thought the tow capacity was 7500 for both old and new? I heard it was related to the transmission, cooling and braking systems...something about some other mid/full SUV's needing a towing package and intercooler (whatever that is) to match the ML.

I admit I don't really know 100% what I'm talking about , just repeating what I've read/heard a few years back.

 

[JoeE46M3]

I think its rated for 7500 in the UK. Same truck?

 

[Da Murf]

How come the Unibody w164 can tow almost 2300 pounds more than our W163's? Body on frame is tougher, power is close to the same, braking is close..

IMHO, it can be explained in one simple word "liability".

They didn't want the exposure by saying that the trucks could tow 7,000 pounds like they do in Europe and elsewhere so they de-rated them to 5,000 pounds to leave a larger safety margin.

Nowadays however they have to keep up with the 'Jones' and were sort of forced by the competition to up the tow capacity of the newer ones.

They could hardly back-track now though and all of a sudden say the older trucks were miraculously able to tow the extra weight now.

 

[Splash]

Don't know the why of it but my local service manager told me (off the record) my 55 was way under-rated and that I should have no problem towing my 6000 lb boat as long as I didn't run 110 mph.

 

[Gene Horr]

3.5 tons is no problem at least for the 8 cylinder models. I have several thousand miles of towing loads in the 2 ton - 3 ton range and one trip of 700 miles towing about 3.5 tons. The comparison is about the same as a 3/4 ton pickup in every category except total load capacity. Handling and braking was better than any 1/2 ton pickup I've used.

As long as you stay under the European limits my experience is that the 8 cylinder W163s are Towing Machines!

 

[marcin411]

All good points but just remember that there will be a noticable difference in braking, acceleration and ride handling when you go from towing 3,400lbs vs 7,000lbs. My favorite tow was a cement trailer, all that cement sloshing around back there made stopping and starting a hoot.

 

[Kajtek1]

With towing it is not the horsepower, but brakes that play major role.
Years ago I've seen Fiats126 powered by 21 HP engine pulling travel trailers over the Alps. Never wanted to be in front of them
With ML320 I was towing my 5500lb boat/trailer just fine. Even the trailer surge brakes were not really reliable I never had a problem stopping.
Than with 3600 lb travel trailer I was passing everybody on grades in Sierra.
I agree with the point Da Murf made here. Liability in USA overcome common sense.
It comes to the point that oil grades are dictated by lawyers, not by engineers.
Our 99 ML320 run on dino oil for several years before lawyers made MB change the policy.

 

[beamar]

I tow a lot with my 05 ml350.

3 tons no prob.


Drove over 1000 miles to pick up a car for my buddy.


car weights 3500, trailer is 1,700ish.


When I take the car to the track, sometimes I squeeze my GSXR in front of the car.


Trailer has brakes, otherwise I don't think I would try towing that much without it.

I also was looking for a way to help keep the rear of the truck from sagging so much. Not sure if there is a better spring/strut setup for these trucks?

Was also looking into a weight distribution setup.

 

[bavenda]

For towing, are you using trailer brakes? Who makes the best trailer controller for our ML's?

 

[Kajtek1]

The best trailer controller is inertia activated. Prodigy is the well establish name on the market. Brakes are required in CA on trailers above 1500 lb.
If your ML is sagging too much, you need to change the weight distribution on the trailer. Collapsible bumper reinforcement is a weak point on the truck, so you don't want to overstress it.
Once I had about 1200 lb on the tongue and the rear didn't sag too bad.
Used weight distribution bars only once, when aftermarket, wider wheels on ML55 were rubbing the fenders on road bumps. Otherwise short overhang ML is one of the best Tow Vehicles on US roads.

 

[Da Murf]

The other point that was inadvertently raised by Splash, Kajtek & Beamar is that what you are towing is nearly as important as what it weighs.

A large boat for example is nearly a perfect thing to tow, it's long and by virtue of it's design the center of it's mass (engine & biggest part of the hull) is almost directly over the axles.

On the other hand Beamar's load is front heavy in the picture (the engine again) and to boot he sometimes adds extra weight (his bike) at the front as well.

This is a double whammy if you have to stop or swerve in a hurry, as the weight transfers forward on the trailer it exerts more tongue weight onto the tow vehicle, thereby lifting the tow vehicles front wheels even more. Remember, the front axle does the majority of the stopping.

This is definitely a case where a weight distributing hitch is needed!

 

[Splash]

Just returned from a 615 mile return trip with new boat. Trailer and 25' boat= 6800 lbs. on tandom trailer. Pulled her along 65-70 all the way with 0 issues; averaged 9.6 mpg. about half what we got on the way up there with no tow. The disk surge brakes on trailer were fine.

 

[beamar]

I was looking into doing a weight dist. setup, just haven't done it yet.


Do any of you guys do anything else when you tow a lot?

I was thinking of putting a trans cooler on it and removing the lines from the radiator.

Here a pic with the bike and car.

 

[Kajtek1]

You don't need the bars if you stay with 500lb tongue rating.
If you go more than that, the first thing you should worry about is reinforcing collapsible bumper reinforcement.
ML sags less under the rear load, than 3/4 ton pickup, so we are talking extremes here.

 

[benzml350]

Have you checked the tongue weight on that setup beamar? It looks pretty heavy on the hitch. With the bike that far up front you might be better off backing the car on.

 

[beamar]

I have not. It's not an easy thing to check, lol. I need to get the scale that does it.

As for backing the car on, I really hate to put that much weight in the back incase the trailer starts to sway..

anyone have any pics of them reinforcing the bumper?

 

[Kajtek1]

easy way to check the tongue weight is using standard bathroom scale rated like 300 lb and piece of 4x4 to distribute the weight in half or 1/3.
That was like 3-rd grade math? Or physics?
For bumper reinforcement make sure you have OEM brackets that hold both sides of the reinforcement, not one like aftermarket stuff.

 

[beamar]

will have to check it out next time i load the trailer.


as for the brackets, I do have them, just the entire kit is an aftermarket kit.

MB thinks all their shit is gold plated.

 

[Kajtek1]

Once again, do you aftermarket brackets have sleeves with bolts that go on the other side of bumper reinforcement, or are they just bend plates like the junk I have in my scrap box?