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I currently have an 04 ml500 that I use to tow quite often with. Absolutely love it.
However, I have 2 small children in car seats, and the interior is just not family friendly enough anymore.
The R class has really hit all of the points I want in my next car.
The problem is, that I need something that can tow our sports car as well. We do a lot of long distance family trips, and bring the sports car with us.
So, my question is... Can the R class be upgraded to tow a car?
I've found little to no information on towing with the r500 / r63.
But I have been told the engine and transmission are the same as the ML... And the limiting factor was the suspension.
Yes it can tow. The limiting factor is the type of hitch installed. The OEM hitch is vastly superior, but it will be an expensive install if you don't DIY.
Engine, transmission, suspension, electronics, etc, are the same in the GL, ML, and R
The chassis should be able to handle it just fine.
Looking at some of the other heads, the OEM is only a class II, It would be worthwhile cutting off the receiver and welding a heavier one on there. I think you'll see in that thread someone actually did that.
The Curt is a class III, but it just bolts to the underside, and hangs down pretty low.
Our current ml500 had a bolt on. Hitch, that ended up bending and almost snapping off during a towing job.
So we welded up a beefier custom brace.
Seems as though something like that may be in order here.
I just wanted to make sure the major components of the car were capable of handling towing what I would need, before setting on finding one as my replacement vehicle come next spring.
If you're game for custom, I think that would be the best route. Might even be cheaper.
You can use the existing steel bumper and add-in the frame tube supports, weld on the receiver of your choice, and put the additional lateral support like the Curt has.
The R-class is basically just a lower ride-height version of the GL with cosmetic differences.
Longer wheel base and wider track always = more stable, but the R only has an additional 6" over the GL, but almost 13" over the ML; so I think you would notice a stability improvement over the ML for sure. The R-class is also the widest and lowest of all three. So weight distribution-, stance-, and centre of gravity-wise, the R is the best towing vehicle out of the three. Weight-wise - it's in the middle.
The rear section of the R-class where the bumper connects looks very robust, but it's hard to tell for sure unless you do some FEA on it or rig it up with strain gages. I have a few clients that do this, I wonder if they could hook me up - so to speak.
Custom work is no problem. We own a performance shop, and have the tools, and/or local hook ups if it's out of our comfort realm.
I was concerned with the structure, that it maybe was not reinforced as much as the suv's, and that was partly to blame for the tow ratings (or lack of).
It's still a unibody, but structurally it's pretty good. Nothing's as good as a frame on body, but except for a G-class MB hasn't made a consumer model since the 1st gen ML.
I had read that actual gas mileage people were seeing wasn't that high?
They also seem to be quite a bit more expensive than the r500.
I had honestly not looked into them very much though due to diesel prices always being quite high... Didn't really see much for a cost savings in the long run (initial car price + fuel costs). And I really am in love with the hp numbers the 63 has to offer.... As absurd as it is to cart 2 kids around on the daily.
The Green Diesel tune deletes the EGR and has a performance upgrade. That's what I've and I'm quite happy with it.
You can also do a DPF delete to free up exhaust flow, but I haven't done that yet.
I agree the M113 engines are good tough engines - one of MB's best V8s. I had a CLK55 and loved it. I had an ML320 also (M112 engine) and it had 370,000kms on it when I sold it - still ran like a top.
Just did some quick reading on it, that's very much up my alley.
Are you aware of any software or tools than can be used to retune the ecu ourselves?
We do tuning in a number of other cars at our shop (we have an awd dyno in house), so wouldn't be opposed to playing with the numbers ourselves (if something like that is readily available).
Now I wonder how well it would take to a turbo upgrade... Haha
Slippery slope... But this may be the best route to get my husband on board with it!
I've got a OBD2 programmer that came with my GDE tune, but I don't have any experience with writing custom tunes, just uploading someone else's predesigned tune.
11-06-2015, 10:12 AM
A quote if I ever saw one... The perfect description. 
