ivrier

I had the chance to take out my 22 ft, 6000 lb trailer over this Memorial Day weekend. I found the towing capablility of the GL was more than sufficient. At first I didn't feel the tow and I felt quite comfortable at 65 mph. However, after around 15 miles of driving I felt that I was being pushed and pulled by the trailer even at a level ground. It felt like I was rocking back and forth. My RPM didn't seem to change and neither did I hear any change in the degree of engine noise. My wife didn't seem to notice. Was it just me thinking that I was towing a trailer nearly equal of the weight to that of the GL or was it real?

Hoping to hear from the experienced towers.

Thanks

Brocktoon

Sounds like it could have been mild porpoising. When this happens, it seems only the driver can feel it, in my experience. Sway, however seems to be worse for everyone but the driver.... go figure.

JimBarnhart

What is your hitch attachment method?

Just a ball and hitch?
Stabilizer bars?
Sway bar(s)?

Also, when the trailer is attached and on level ground is the truck level and is the trailer level?

ivrier

The car is level when hitched to the trailer.

The Equalizer hitch is adjusted accordingly to the height of the vehicle. The more I drive the Gl while towing the trailer, the more comfortable I feel. I guess I have to get used to the fact that I am towing a trailer close to the weight of the GL.

http://www.equalizerhitch.com/

JimBarnhart

I wanted to make sure you had a solid hook-up first before speculating what the problems might be.

The equalizer hitch is a good choice. I don't have personal experience with it, but the combination of weight distribution and sway control looks solid. My experience has been with friction control sway bars (e.g. Reese) and a separate weight distribution hitch.

Have you been towing trailers before and have lots of experience, or is this an introduction to towing along with trying it with the GL?

My guess is you are exactly right. You have a trailer that is nearing the weight of the vehicle, it getting near the threshold of pullability (GL is rated for 7500 lbs) and you just need to get used to it. My experience has been towing something that is below about 2/3rds of the rated towing capacity for the vehicle is almost unnoticable when pulling, but when you get beyond that point it becomes noticeable and requires some attention.

I've had a lot of different combinations of tow vehicles and trailers over the past 10 years or so. I have had situations where the trailer seems to sometimes push/drag the tow vehicle, even at steady rate of speed, which sounds like what you experienced. I have found that it seems to be speed related. Going a few miles an hour faster or slower usually solved the problem.

It's not uncommon to feel pushed or pulled when changing speeds, especially when slowing down since the trailer brakes and the GL brakes are never perfectly aligned.

I hope this helps and isn't viewed as condescending.

ivrier

Thanks for the reply Jim. Yes, this is my first experience in towing and I am definitely a novice. I guess I will have to get used to the fact that towing is a completely different experience and that pulling and dragging is a very normal. I do not have any plans of adding more weight into the trailer by piling up equipment into it. I have a Thule box which I plan to fill up with if necessary.

jpb7104

I have a GL320CDI and couple it with a 25' Airstream trailer using a equilizer hitch. The GL handles it very nicely although I usually keep my speed around 60 MPH when towing.

Chasen1211

Hello, new to the forum, and have a few questions on towing with a GL.

I have a GL450 and am planing to buy an enclosed car trailer. My first question, is there any more wiring that needs to be done for electric brakes that are on the trailer? Is there anything more I should worry about if I'm going to be pulling close to 7000lbs?

TIA,
Chasen

Stumblefoot

Sounds like a case for Danno4x4!

ivrier

Here is the link to the lengthy discussion on brake controllers. I was very anxious with the wiring but it was taken cared of by the installer without any problems.

Enjoy

https://mbworld.org/forums/showthrea...ntroller+brake

TIA,
Chasen[/QUOTE]

Danno4x4

Chasen,

You will need a Trailer Brake Controller... There are quite a few on the market to choose from, but the one I like the best is the Tekonsha P3. The Trailer Brake Controller will plug right into the existing wiring harness of the GL, but you will have to create an adapter to make it work... Your dealer can do this for you or you can do it yourself, take a look at this thread to see the details...
https://mbworld.org/forums/showpost....98&postcount=6

Without the trailer brake controller, you are limited to only towing 2000 lbs or so...

Also, with a 7000 Lb trailer, you will probably want to consider getting some kind of Weight Distribution Sway Control towing system for longer trips... It helps make the entire vehicle more stable in windy conditions, on bad roads, and when you get passed by the occasional semi truck going the opposte direction. It is possible to get by without it, but the driving will wear you out quickly as you will need to spend a lot of energy on making little steering corrections to stabilize the trailer...

Here are the two that I currently have my eye on...

http://www.etrailer.com/pc-wdpssc~49...utm_medium=ppc

http://www.equalizerhitch.com/

StevethePilot

Sez who?

Danno4x4

Okay a slight revision to my statement... Not having a trailer brake controller isn't the limitation... The limitation applies for towing trailers which are not equipped with brakes...

There is a type of trailer brakes called surge brakes, which uses the inertia of the trailer to compress a cylinder just behind the hitch coupler which activates the hydraulic brakes on the trailer... These are stand alone and do not need a trailer brake controller to work...

However, if the trailer is equipped with electric or electro-hydraulic brakes, you will need a trailer brake controller to control them.

The limitations for towing braked vs. unbraked trailers can be found in the owners manual... In the online manual it can be found at the below link where it refers to trailer loads. It is in metric units in the online manual, but the limitations still apply.

http://www4.mercedes-benz.com/e/cars...d13e52640.html

StevethePilot

Two things; I'm going to verify that's in the U.S. manual as it might be a regulatory thing rather than a practical thing, and more importantly I'm never going to tow a metric trailer.

Brocktoon

It's not in the Canadian manual, which I'm sure is the same as the US one.

Made myself a harness with the correct MB plug on one end and the Tekonsha plug on the other with the circuit breaker in the hot line in like 10 minutes. The MB blades were a bit funny to crimp, but the whole thing from finding the plug to testing the trailer was less than an hour, for those who care.

Danno4x4

It turns out that it is not in the US version of the manual either... ?!?!? That is strange... I would definitely not recommend towing anywhere near the 7500Lb capacity of the GL without Trailer Brakes... I am surprised. As thorough as the MB manuals are that they left this one out.

Glad to hear that creating the harness was a breeze for you... Its really not that hard... Of course, I soldered all of the connections both for the MB Blades and the Fuse holder for the Circuit Breaker, but I am just **** like that

Brocktoon

Yeah, looked like it could use a solder, but my iron burnt out, so it's a project for another day...

StevethePilot

I'd say this; don't tow anything until and unless your hitch is repaired, but I'd hate to be MBUSA if they say you can tow 7500lbs and don't say you have to do it with trailer brakes. I'd believe that a) trailers over a certain weight almost always have at least surge brakes, and/or b) the brakes on the GL somehow are able to handle the 7500lb stopping weight - at least once! I know it's not the engine that's the weak link.

Brocktoon

- My VIN is not in the recall
- You are wrong about surge brakes unless you are talking about boat trailers.
- You are prolly right about the once part.

scottybdiving

They don't have to. The law, I'm pretty sure in all 50, requires brakes on all tandem axle trailers. It is a given that any trailer legally grossing 7500, is going to be a tandem. In this case, the law trumps the manufacturers recommendations.

StevethePilot

I think there (again) may be differences between US and Canadian regulations with regard to trailer brakes. As Scotty said, anything in the 7500lb range will be tandem axle, and that automatically has brakes (I guess either surge or electric). Now, for both you and Scotty, with that said, I can again reiterate that I have a wealth of ignorance on the subject, but also with that said, I am exactly the guy that needs it spelled out for him in the manual. (Except, of course, that I'm here on this forum, so you guys are making it clear to me.)

STP

Brocktoon

I just meant that you will only find surge brakes on a boat trailer that heavy, all others will be electric, or maybe air if it has a heavier maximum rating, not to say that you don't need brakes!