anothercar

This is the perfect thread. Ordered '15 GL 350 BlueTec last week expressly for the purpose of towing the Airstream. Expected delivery is late October and y'all have answered my questions about brake controller and anti-sway hitch. My GL is Obsisian with Auburn Brown leather. Can't wait!

sbvol

This thread truly delivers. I was considering purchasing the Airstream Interstate because I didn't believe the MB 350 could tow an airstream trailer. You (this thread) has given me the confidence to move forward. Now I have to figure out which trailer. I'm thinking Land Yacht but I need to do more research. That vintage rig looked pretty sweet as well.

blittle

Just have to comment......back in 1959, my dad ( an Air Force officer ) was transferred from Montgomery Alabama to Anchorage, Alaska. He decided to drive!!! Bought a brand new 59 Dodge station wagon and 14ft. Sportcraft camp trailer.......towed that thing...with me, my mom, one dog and one parakeet all the way up there in 16 days.....1200 miles of dirt road ( the Alcan ) Spare tires? run flats? .....we had a 5 gal can of gas in the back.....two spare tires stored in the trailer, another 2 gal of drinking water stored as well! Great memories....! By the way ..... the 59 Dodge made the return trip 4yrs later.....and continued on to 1968! PS: we had to stop for 1 forest fire, two mountain lions, and one bear!

Hammer1

Just finished 3 weeks of boondocking in Idaho and Montana ending up in Southern Oregon at Alumafandango. The whole trip was without incident. The GL350 pulls effortlessly.

Average MPG = 15.5. That is with 6 huge mountain passes. On the flat at sea level we got about 17 MPG.

I purchased JMCarters' identical rig: 28' International Airstream + ProPride hitch (thanks Sean Woodruff) and the MB 350GL. The GL350 is a monster. Plenty of torque and I'm sure it would pull Airstream's largest Trailer. The ride is fantastic and we really never knew the trailer was behind us even in strong winds.

Thanks to JMCarter for emailing me his set-up. I took the TV and trailer to the scales and had perfect weight on all axels with his set-up.

I did use the Direct Connect brake controller and it worked perfectly. Recommended.

I'll post some pictures when I get settled down and have time.

JMCarter

You're welcome Hammer1. We did over 12,000 miles this summer in the UP, Ontario, and New England and the GL was flawless, a summer to remember. Next year it's back out west...happy towing.

anothercar

The new Land Yacht 28' starts at $145k!! You could buy two 25' Flying Clouds for that price. Wow!

Hammer1

Here it is. The culmination of Rich Luhr and Carter's help:


Thanks to everyone I mentioned and several others including Sean Woodruff.

Regalflyer

Hi folks, newbie here with towing experience using conventional pickup and a 5000 lb trailer. I have been so blown away looking at what the GL is towing, but very concerned about tongue weight. I would love to have a GL/airstream combo, but I am Leary of the specs. Most of the airstreams are over 700lbs dry unloaded, doesn't that exceed the specs on the GL?

Thanks for experience & info
Looking before leaping!

Hammer1

Let's limit the discussion to Class IV hitches since they are going to be the hitch class used by the GL350.

The specs on this hitch as defined by the defined by the Society of Automotive Engineers (SAE), not the automotive manufacturer, are as follows:

1 Class IV hitches are weight carrying (WC) and weight distributing (WD) hitches depending on the vehicle and hitch specifications.
2 Not all Class IV hitches are rated to be both. See the specific hitch for that information.
3 Class IV hitches used as weight carrying are rated up to 10,000 lbs. gross trailer weight (GTW) with a maximum trailer tongue weight (TW) of 1000 lbs.

In other words, the class IV hitch can pull up to 10,000 lbs of trailer and are designed to support a tongue weight of 1,000 lbs or 10% of the weight of the trailer.

I believe the tongue weight rating of 10% is chosen because it is 10% of the trailer weight and the current thought is that 10-12% of the trailer weight must be moved forward to place the Center of Gravity (CG) away from the tire patches and closer to the TV in order to maximize the stability of the trailer (in terms of yaw and sway).

Now lets get right to the GL and what this means. Mercedes states that their GL and hitch as a combination system is rated by Mercedes to be able to handle a pull, from a dead stop, of 7,500 lbs of trailer on a 12% grade. This means that the transmission and everything else is rated by Mercedes to be ok to perform within this operational envelope. The GL was designed to pull a fully loaded trailer, up to 7,500 lbs GTW, in every day conditions that assume a 12% grade as a maximum dead pull circumstance. So far so good.

Now, onward to Tongue Weight (TW). TW is the amount of downward force the trailer receiver places on the tow vehicle's (TV) ball. As defined by the SAE, the hitch should be able to support at least 10% of the trailer weight, because the SAE believes that 10-12% of the trailer weight should rest on the ball of the TV for best stability. Every American auto manufacturer quotes a 10% rating for their hitch. For example, if the auto manufacturer rates the tow capacity of their truck and hitch (GTW) as 7,500 lbs, they will always quote the TW as 10% of that number to be in agreement with the SAE definitions.

In Europe, the rating of the amount of weight that should be placed on the TV ball is much less. There are several reasons for this and none have to do with what is safe. The european ratings are based on the fact that their trailers do not generally utilize weight distribution and their TVs and trailers are generally smaller.

In Europe the rating of the Class IV hitch is thought to be such that the TW should be 8% of the (GTW). So, Mercedes rates the correct maximum TW as 600lbs or 8% of the GL's rated GTW. If, this was an American manufacturer they would rate the same vehicle and hitch as having a max TW of 10% or 750 lbs, I believe. It is always the same 8% X GTW for the European TW rating of their vehicles and 10% X GTW for the American ratings.

Conclussion: The Mercedes GL has a TW rating more like 750 lbs when compared to the way American manufacturers state their TW ratings. Just me, I would consider the Mercedes GL to have a TW rating of at least 750 lbs.

Regalflyer

The International Serenity tongue weight being 950 lbs plus the weight of the hitch, and cargo including water, what did you get your rear axle to weigh with that setup? I did see that the GL350 has a payload rating of almost 1,700 pounds.
Thanks,
Looking to do the same- especially after towing with a pickup and no air suspension.

Hammer1

Hello Regalflyer,

Our International Serenity FB has a TW of 770lbs.

Unhitched: The GL350 weighed on the scales at 3000/3060. Front/Rear

Hitched: 3060/3920/6540 Front/Rear/Trailer

These are Axle weights. The trailer was full on water and LP. Two adults and an 80lb lab in the back seat. We had a generator and 100lbs of gear in the back of the GL350 that we now throw in the back of the trailer behind the axle. We also have trimmed about 200 lbs of gear from our kit and have tried filling the water tank when we get there. None of these things seemed to make a difference in my impression of the towing experience, which is effortless and stress free. The hitch I use weighs about 200lbs. I suppose that you could fill your water when you get there, but these numbers are within the axle and GW listings from Airstream and Mercedes. Mercedes Axle weights listed on the door are: 3417/3978. Front/Rear

I am sure that the way we pack now the rear axle weight of the GL350 would be down at least 200lbs from our scale readings.

Hope this helps you decide if you are comfortable with the GL350 as a TV and feel it is safe.

Rick


Here is the printout from the CAT scale:

Regalflyer

Many thanks, those numbers indicate that your setup is well within the front and rear GAWR, and your entire trailer weight is well below the 7500lb rating of the GL.

I am hoping to get numbers from someone with the 28 also.
Great help from this forum, thanks again.
Paul

Hammer1

Those numbers I posted are from our 28" Serenity. JMCarter also has the same TV and trailer. He weighs out the same at the CAT scales.

Regalflyer

Arrggg,
Ok, the 27FB is 28 feet long, that is what you and JM have right? The model 28 is 27 feet 11 inches and has the 950 lb tongue weight, that is the source of my confusion. We are looking at the model 28 with twin beds, and that puppy has the 950 lb tongue weight.

Max4Speed

I use my 2014 GL550 to tow the GT-R to events. PERFECT tow vehicle. Just need to order the extended mirrors.

cyclrder

Nice setup! How much weight in total do you think?

deeperblue

Hi, Hammer1:

It seems that you live in Seattle area. I live in this area too. Have you had your hitch re-enforced/beefed up? If yes, where?

I know everyone recommends Can-Am RV, but that is just too far from Seattle.

Thank you very much!

Max4Speed

The GT-R is around 3800 or so and trailer is 3000. So I am under the 7500lb load. Sometimes I have to look behind to make sure trailer is there because the pulling is so effortless.

Dog hauler

Posts 34 and 36 make my head spin! Mercedes says the maximum tongue weight for the GL350 is 600 lbs. There is no mention that use of a weight distributing hitch increases allowable tongue weight. What are people doing about the tongue weight limit of their GLs?

While my trailer weight (fully loaded) is only about 5800 lbs., I'm having trouble staying within the 600lb tongue weight limit. And from what I can tell, tongue weights on the Airstreams that are the topic of this thread are more in the 700 - 900 lb area so other folks have this problem, as well. The web sites for the anti-sway hitches that are mentioned here don't say anything about being weight distributing hitches so I'm not sure how they might help with the tongue weight issue.

So, I'm basically pretty confused and at a loss for what to do if my tongue weight climbs to 900+ lbs, as it would if I wasn't very, very careful about how I load my trailer. What can I do about the rather dainty tongue weight limit of my GL?

Max4Speed: Your set up is similar to mine, though both my trailer and the car that goes inside it are much lighter than yours. What do you do about too much tongue weight?

Jordan Bursch

HELP! I purchased a 2015 GL350 new from the dealership here in Southern California and it didn't have a hitch installed. I am having a difficult time getting a straight answer from them as to the cost of installing the hitch, wiring, and electronic braking system. Is there a shop that anyone can refer me to in Southern California that can help me out? My dry weight will be right around 6500lbs. Thanks.

sstrohm

Cefcore, did you have any problems with the Prodigy RF? I have heard that there are challenges getting the RF brake controller to actuate the brakes because it isn't receiving a signal from the MB. Thanks, Woody

zimirza2003

I had to wire the controller after getting the wiring diagram for the GL and Brake Controller. There is no connector available to match with GL existing connector. I have Tekonsha Prodigy P3 controller which works well with my Airstream. Already driven over 30,000 miles
Good luck
Zia

Colby Turley

Thanks for the post above. It is very helpful. I have a 2009 GL450 and was considering a travel trailer that weighs about 5300 pounds and has a tongue weight of 680. It has been around 3 years since your post. Have things been good for you? Reading some of these post like yours makes me feel more confident about the truck.