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Hi Guys,
I have a 2007 GL450 with almost 200k miles on it and looking to upgrade to a new GLS. I've driven this thing hard and have done a lot of towing with my GL450 from travel trailers, to boats, to dump trailers, and more. The GL450 only has a tongue weight of only 600lbs (although I've exceed it several times). I feel that this is Mercedes weakness when it comes to trailer towing specifications. Most if not all US trailers have a tongue weight of 10-15%. With the new GLS' max towing capacity of 7,700 lbs, this would mean a maxed out trailer would have a tongue weight between 770lbs to 1,155lbs. I've dug through MB's website and even talked to a couple of dealers but I cannot find any information about maximum tongue weights when using a weight distribution hitch. I'm also quite disappointed that Mercedes still does not have an option for an integrated brake controller that can be found in other SUV's with similar towing capacities (GMC Yukon, Ford Expedition, Chevy Tahoe, etc). I really don't want to drill holes in my new lower dash on the GLS that contains the knee airbag.
Has anyone been able to find any published information on from Mercedes on towing such as this towing guide from Ford? https://www.fleet.ford.com/content/d...owingGuide.pdf
I really have enjoyed my GL450 and have thought it was a good tow vehicle but thought it could be even better.
There are two fairly long threads in the GLE V167 section. I suggest reviewing them, because your points are addressed, you only need to check differences, if any, between GLS and GLE towing specs.
Look underneath the rear bumper of a GLS with a drawbar, and there will be a label. Take a picture of it and understand the ratings it communicates.
There are two fairly long thread in the GLE V167 section. I suggest reviewing them, because your points are addressed, you only need to check differences, if any, between GLS and GLE towing spec
Cross referencing to the threads of the GLE X167 (2019+) forum.
I have a 2011 GL350 with just over 100,000 miles, about 25,000 of which have been towing a 30-ft airstream trailer. The kids and dog and I visited more than 20 national parks this summer in an epic cross US adventure and we towed the Airstream for about 10,000 miles over 2 months...
Back in the day of your and my early GL's, the welds between the hitch receiver and the bumper were known to be substandard, so many of us reinforced our hitch receiver. I welded triangular gussets into mine. I understand this was fixed later in the GL production cycle.
The tongue weight capacity of the GL and GLS is a function of the strength of the rear body, bumper and hitch receiver, plus the load carrying capacity of the axles, plus assumptions about the weight of passengers and cargo. I did a long post years ago after analyzing the weight capacities of the GL and the numbers added up - the 650 lb tongue limit absolutely includes assumptions about how much cargo and passengers you were carrying. Hence when I tow I never carry any cargo in the GL. Grossly generalizing, 100 lb of cargo you are not carrying means a hundred pounds more of tongue weight your truck can handle and stay in spec.
Mercedes corporate or USA has never mentioned anything about weight distribution. A weight distributing hitch is going to put much more stress on the body and bumper and those welds to the hitch receiver in exchange for reducing the amount of weight carried by your rear axle. I have no idea what the weakest point in the chain is, and certainly Mercedes won't tell. My anecdotal experience is that at 100,000 miles I haven't yet needed to replace my rear axle bearings, and I don't use weight distribution...
I think it's highly unlikely Mercedes will ever build in a brake controller. Vanishingly few Mercedes customers use their GLs to tow- we are not the typical demographic for them. I run the wires from the green towing plug in the driver's foot well underneath the floor mats and I have my tow controller velcroed to the carpet on the floor under my left leg. this allows me to remove the controller when I'm not towing, protects the wires, and means that controller is firmly mounted where it's easy for me to reach and to confirm it's on and working. I've never had a problem with the setup in many many miles of towing, and I disconnect the controller and put it in my glove box when I'm not using it.
I ordered a GLS 580 and will likely also be using it for towing the airstream. I had three different dealers talk to their techs about the GLS 580 and towing, but their level of knowledge is not much better than it was 10 years ago when I bought my GL350. I also made a post here after going through the GLS owners manual about which autonomous driving features are enabled in disabled while towing. The dealer's techs were wrong about much of this.
The net is I don't think you're going to get much more than anecdotal information from other owners about towing, particularly about towing large loads. Mercedes just doesn't make this available from a corporate perspective, and the dealers don't deal with towing very often.
One suggestion is you could post in the x164 forum and ask who is using weight distribution and their experiences. Many people have worked with a guy named Andy at Can-Am who seems to have the most experience of anyone in the world in setting up or modifying GL's in GLS's to make sure they are adequately strong for towing. You can find his contact information via Google or in the x164 forum...
This is an old thread, but I just came across it. I bought my 2014 350GL, as the GLS was called then, new for the purpose of towing a car hauler trailer. Trailer weight loaded was 6500#. I found that I needed to have tongue weight at around 900-1000# for stability purposes. The vehicle pulled the trailer many thousands of miles, including up and down mountains, The transmission did some hunting for gears but the vehicle otherwise performed very nicely as a tow vehicle.
I was unaware of the 600lb tongue weight limit when I bought the GL and for a good part of the time I owned it (sold in 2019). Once I became aware of the tongue weight limit and knowing I was towing at the better part of twice the limit, I researched it. First off, I discovered that MB says to not use a weight distributing hitch. Next, an auto shop owner who has years of experience with trailer servicing and repair told me that the very low weight limit and recommendation to not use a weight distributing hitch owes to the way MB attaches the hitch to the vehicle because it makes it more susceptible to tearing clean off the frame.
The rest of the story is that once I discovered all this I sold the car and bought (what I thought was) a far more robust tow vehicle. You know, a man's tow vehicle, not some girly-man, pinky in the air, dainty MB. So I got me a s**t kicking, pavement pounding Ram pickup. Okay, okay, it was only the 1500, but still not a girly-man ride.
Well, guess what. The GL was a far better tow vehicle than the RAM. More comfortable, for one, although the Ram is pretty good in that department. But far more importantly, the MB handled the load much better than the Ram. Towing the very same trailer, the MB transmission hunted gears much less than the Ram. And here's the shocker: the MB air suspension worked just fine despite the overload on the tongue weight. The Ram air suspension, on the other hand, is completely inoperable "due to payload weight" says the warning on the dash. The payload weight being just me in the driver seat and the tongue weight of the trailer. This is even though the Ram trailer weight capacity is 11,500# with a max tongue weight of 11 or 1200#. Go figure.
I'm moving over to a GLS from a Suburban with a Diesel. I've towed many thousands of miles with unibody and body on frame, and while BOF does do a better job of isolating trailers shock and movement from the passenger compartment at the loads that these are rated to tow it is negligible. I tow on a weekly basis from March - November, so the GLS will be getting a workout.
It's an overused cliche but between the torque of the diesel, 10 speed trans and full air suspension, you literally cannot tell that there is a trailer behind my Suburban. I'm not expecting that out of the GLS but have seen these things put through some work in threads like this, so even while it is a bit of a downgrade in capability it will still serve me well.
I'm still 2 months out from my delivery but will remember this thread and post back once I have photos of the hitch and such. I'm probably the only person to ever get under a vehicle in the showroom at my local dealer here - but things are pretty robust down there on the X167 and I have no qualms about sticking my 5,000LB boat/trailer combo behind it after having a look and some strong shakes and bouncing on it.
Last edited by MDMercedesGuy; 11-03-2023 at 11:34 AM.
I'm moving over to a GLS from a Suburban with a Diesel. I've towed many thousands of miles with unibody and body on frame, and while BOF does do a better job of isolating trailers shock and movement from the passenger compartment at the loads that these are rated to tow it is negligible. I tow on a weekly basis from March - November, so the GLS will be getting a workout.
It's an overused cliche but between the torque of the diesel, 10 speed trans and full air suspension, you literally cannot tell that there is a trailer behind my Suburban. I'm not expecting that out of the GLS but have seen these things put through some work in threads like this, so even while it is a bit of a downgrade in capability it will still serve me well.
I'm still 2 months out from my delivery but will remember this thread and post back once I have photos of the hitch and such. I'm probably the only person to ever get under a vehicle in the showroom at my local dealer here - but things are pretty robust down there on the X167 and I have no qualms about sticking my 5,000LB boat/trailer combo behind it after having a look and some strong shakes and bouncing on it.
IMO the only thing a body-on-frame is better is road isolation. The GLS eliminates a lot of the BOF frame flex and is a much more stable towing platform.
You will be using more revs on hills with the gasser than with the diesel, but aside from that and maybe the need for extension mirrors (Milenco BTW), you will be pleasantly surprised.
If your Suburban was a half ton, the GLS will tow better in every way. Every way. If it was a 3/4T, it would have only one advantage: more payload.
Regarding your hitch, I hope you have a factory hitch, because all the aftermarket hitches I've seen have pretty sketchy attachments, so I'd limit my towing to 3k pounds or so.
The factory hitch is plenty strong for its rated 7,716 lbs (3,500 kilos, a tax and licensing limit in some markets).
Your limit will be payload, which will probably be around 1200#, but that still leaves a "reserve" of @400# per axle (GAWR) and @800# total GVWR.
I push the payload (which includes the hitch itself and the tongue weight.
I verify at the scales once, to make sure I'm not exceeding any of those limits.
Then the reason for the mirrors would be to make sure the trailer's still there!🤔🙂
IMO the only thing a body-on-frame is better is road isolation. The GLS eliminates a lot of the BOF frame flex and is a much more stable towing platform.
BOF is widely regarded as being superior for towing in terms of strength and isolation. A thru bolted hitch on a frame is infinitely stronger than a hitch bolted to a monocoque.
I am sure the GLS will be great at towing, and I’m crossing my fingers that I’ll have the boat out in another month or so and get to put it into action - but let me be clear, I’d prefer it be on a full frame any day of the week for towing.
If your Suburban was a half ton, the GLS will tow better in every way. Every way. If it was a 3/4T, it would have only one advantage: more payload.
It was a half ton, all T1 chassis SUVs are half ton.
Hands down, there isn’t anything that tows like a Suburban. The GLS is the compromise I was willing to make - but it’s not best of breed for this regardless of stated capacity. Between the isolation, stability and control the wheelbase gives - there is a reason why they sell like they do for folks pulling horse and travel trailers.
I ordered every trailering feature they offered (in spite of about 300k miles spent towing in my life and backing trailers since I was about 8), I even sprung for the self backing feature, just for the gimmick. I’m quite happy with the GLS, and it does a lot of things well - but I’m old school with towing and will always prefer my hitch bolted to a frame n
Body on Frame is might be better than a stout Euro SUV if the road never turns, there is no irregular surface, and you don't have to stop quickly. (The stopping part is brake size and suspension superiority though, not the chassis.)
Evasive maneuver? Forget it.
I agree that the enclosed body of a Suburban (or van) on a 15' mild steel C-channel is an advantage over a pickup, but leaf springs and poor geometry are just some of the factors that keep the BOF tow vehicles from being as stable as any Euro SUV with a factory hitch. (BTW have you looked at that skinny tab of metal that the hitch bolts to on a Suburban? It's puny.)
Yes, Suburbans are legendary, but they're not necessarily the best. They are at their best arrowing straight ahead on an interstate. Back when they were 3/4T.
The GLS will surprise you, especially if you tow on secondary roads.
I use a GLE now, but my three previous TV's were diesel Euro SUV's. Before that I used 3/4T vans after switching from 1T pickups (Chassis flex). Each step was an improvement in the towing experience.
I've also been in a couple situations with bad winds that had semis and 3/4 tons on their sides, but the Mercedes pulling my 27' 6000# RV just laughed. Mileage fell to 12, though.
I'm ranting, but the GLS will be excellent if you pay attention to weights. Superior, even.
Body on Frame is might be better than a stout Euro SUV if the road never turns, there is no irregular surface, and you don't have to stop quickly. (The stopping part is brake size and suspension superiority though, not the chassis.)
Evasive maneuver? Forget it.
Hogwash.
The 70-0 braking on the T1 Suburban is about 8 feet longer than on the GLS in instrumented testing. The Suburban has a significantly longer wheelbase, contributing to greater stability and tracking. Case in point - loaded or unloaded, a Suburban doesn't tramline, and the GLS is pretty damn bad over rough pavement. The ride over broken pavement is not in the same ballpark in terms of passenger compartment isolation (and on a unibody, those same harmonics are being passed to the trailer).
I agree that the enclosed body of a Suburban (or van) on a 15' mild steel C-channel is an advantage over a pickup, but leaf springs and poor geometry are just some of the factors that keep the BOF tow vehicles from being as stable as any Euro SUV with a factory hitch. (BTW have you looked at that skinny tab of metal that the hitch bolts to on a Suburban? It's puny.)
The T1 generation Suburban doesn't have leaf springs, firstly. Secondly - the frame is fully boxed and the attachment points are high strength steel. I've spent an extensive amount of time under them, actually... mind you automotive engineering is my background. Theres a reason the GLS has an off ratio tongue weight rating...
Superior, even.
I love my GLS. I am very happy to have moved over to it as a daily (although I lament my loss of space behind the 3rd row, but choices...). It is far from perfect, however.
I'll be glad to see how it tows, but fundamentally, BOF has a purpose - and historically it is better for towing.
Let me add a couple of things about European tow ratings. They are not comparable in any way to U.S. standards, or the j2807 SAE tow standard.
First, in many European countries a higher tax applies to vehicles over 3,500kg towing capacity. AKA 7716#. In many it also requires a different license in order to operate.
So that's the reason for the 7716# you see everywhere.
There isn't really any relevance to strength or tow ability - It's red tape.
Second, RVs in Europe are (were) dinky little things, with single axles and tongues that one person could carry, hooked up to sedans. Weight distribution hitches were shunned because they were American.
Thus, it became a convention that the tongue is automatically 8% of the trailer weight. That's where that odd 617 lb tongue weight came from, not any engineering calculation. In recent years the convention went to 10%, but again that's only a convention and not an engineering consideration. So we see 770 lb - still just a ratio.
In the early 164 SUVs, The hitch itself was sub standard and needed reinforcement, through about 2010. In mid 2010 they changed hitch suppliers and the reinforcements were no longer needed. (I had my 2010 reinforced just in case but it wasn't needed after all. I got peace of mind.)
In the 164 and 166, the factory hitch increased internal chassis reinforcement as part of the assembly. It was very expensive to install it aftermarket because of the disassembly required to install the reinforcements. Somewhere I have exploded diagrams that show those.
I don't have that detail on the 167s, and Mercedes no longer sells the retrofit hitch package - It's only available as original equipment.
Based on their history with chassis reinforcement for hitches, I'm going to make a guess that there continues to be internal chassis reinforcement for OE hitches. Visibly, the rear crossmember also looks larger.
I have never seen a report of a factory hitch detaching from the car, either here or on the Airstream Forum. However, I have seen some reports of aftermarket hitches tearing loose, but what do you expect if you're just attaching to a non-reinforced point? That's probably not a good idea.
The Euro towing history that I mentioned above, is from Andy Thomson from Can-Am RV. You can Google that site and find all kinds of information about towing, including on-track comparisons of pickups, sedans and SUVs. It's a good source.
Hogwash.
The 70-0 braking on the T1 Suburban is about 8 feet longer than on the GLS in instrumented testing. The Suburban has a significantly longer wheelbase, contributing to greater stability and tracking. Case in point - loaded or unloaded, a Suburban doesn't tramline, and the GLS is pretty damn bad over rough pavement. The ride over broken pavement is not in the same ballpark in terms of passenger compartment isolation (and on a unibody, those same harmonics are being passed to the trailer).
The T1 generation Suburban doesn't have leaf springs, firstly. Secondly - the frame is fully boxed and the attachment points are high strength steel. I've spent an extensive amount of time under them, actually... mind you automotive engineering is my background. Theres a reason the GLS has an off ratio tongue weight rating...
I love my GLS. I am very happy to have moved over to it as a daily (although I lament my loss of space behind the 3rd row, but choices...). It is far from perfect, however.
I'll be glad to see how it tows, but fundamentally, BOF has a purpose - and historically it is better for towing.
I apologize for being so behind the times on the T1 Suburban. They've made some very necessary changes and moved into modern times.
Boxing the frame was important, but you're certainly not going to get the bend strength, torsional rigidity and stable platform that you get with with a Euro unibody.
I definitely don't subscribe to the longer is better and heavier is better in a tow vehicle. I've been thrown into a ditch, driving a tow vehicle 4X the length and 2x the weight of the trailer. A bigger Hammer isn't always the best tool.
I wasn't able to tow with my 167 because my trailer got totaled by hail the day before I was going to head out, but I'll say my 164 and 166 were entirely in control of the 6,000 lb trailer, and you'd never know it was back there if you didn't look behind you. As you said about the Suburban.
Based on the overall improvements in the 167 chassis, I expect a dramatic improvement in towing ability with the 167 over the 164/166.
Read my previous post above for description of why Euro hitch ratings are so odd. It's not lack of strength.
Your payload is still going to be the limiting factor, specification wise.
It's all good.
My information is certainly not hogwash though.
10-17-2020, 10:41 PM
