I have searched the site for anything to do with towing. There are certainly many threads about installation of hitches and brake controllers but and I have found little mention of how to hook up a trailer using a wdh and the airmatic suspension. I have a 2015 GL350BT with the 550 option, I do not have ADS or off road package just one button to raise or lower the vehicle. I bought the vehicle last year and am now getting ready to tow my travel trailer. I found a you-tube video last year of a fellow showing how he hooks up his gl350 to his trailer but I can't find it again. What I have surmised is to put the trailer coupler onto the receiver ball with a little weight, hook up and tension the wdh bars then put the rest of the tongue weight on the vehicle. does this sound correct? Also the other question is about uncoupling the trailer do any of you Travel Trailer towers have any procedures for that? All you fellows who tow your Airstreams and other Travel Trailers please let me know does this procedure sound about right? I have read all of Mercedes info about towing and making sure doors are closed etc., but would still like RV'ers perspective on this.
Thanks,
Bob

 

I don't tow with a weight-distribution hitch, but this thread may help.

Jeff

 

I tow with a WDH on my 2013 GL450 (factory tow package, with Tekonsha brake controller plugged in under the dash). I tow a 33' Passport Ultra-lite, it's about 5500 pounds dry and 7000 pounds fully loaded. I don't tow with water tanks full. I have adjusted the weight of the trailer so the tongue weight is ok for the GL (I moved the trailer spare tire from the tongue to the rear bumper and load the heavy items over the trailer axle or rear of the trailer axle). I know this is worse for sway, but my hitch setup also has anti-sway (Equal-i-zer brand, I highly recommend it!) so sway is not a problem at all for me. I don't put a full load of people and gear into the GL when towing heavy trailers, to keep the weight on the rear axle of the GL within safe limits. The GL tows beautifully, it's very smooth with the air suspension. I took my trailer over the Rocky Mountains last summer, a 2500 mile round trip from my home near Portland Oregon to Yellowstone National Park and back. 70mph legally in Montana! (I can't say what I actually drove at, I found that at 70mph I was getting passed by semi trucks and that's just too embarrassing for me). I also upgraded my tires to a heavier-duty rating so I can air up to 50 psi in the rear, and about 45 psi in the front for towing. The Equal-i-zer hitch has the weight distribution bars at a pre-set height (measured and calculated and adjusted when installed the first time), so it doesn't matter if I connect the trailer with the engine on or off. Although who wants to kneel down and suck in exhaust fumes while you hook up?? Turn off your engine, save your brain cells. If your WDH needs adjustment every time, then make sure the engine is off and follow the procedure in the link that Jeff posted above. One last thing, I put extension mirrors on my GL when I tow, the GL has small mirrors that are not big enough for long trailers. Oh, and one MORE thing, I put a cheap aftermarket wireless TPMS system on my trailer (screws into the valve stems) so I can monitor the trailer tire pressure while I'm in the GL. Drive safe!

 

Do you have a tow package on your GL, meaning factory harness and the whole bits, If so you can put on a brake controller, the vehicle should know you are in tow once all is plugged in. You can use the paddles to gain motor speed. You can tow in sport or comfort. Sport will wear out the tires more if you have too much tongue weight.

 

Yeffsy,
Thanks for the link, that is the thread that I got the most useful info so far. Thanks for all the info oldmangrimes, I am not far from you only an seven hour drive up here in Vancouver, B.C. I have extension mirrors that I bought when I towed this trailer with my Envoy, and I am pretty sure they are mandatory most everywhere. I bought my TT new in 1996 and have traveled all over the west as far down as Carlsbad Caverns over to Pikes Peak, to the Petrified Forest and everything in between. My kids did all the travel planning and we certainly saw everything.

 

There is a video on you tube from Canam RV putting a large trailer and a gl350 through the paces on a track to show Mercedes stability control system. It is Impressive. Watch it , and yes I think I mentioned I had the 550 option, just picked up the pins and plug housing today to wire the controller.

 

This is probably that Canam RV video you mentioned. I had to go looking. It's worth a watch.

Jeff

 

I tow a 2021 Micro Minnie 2100BH with a Bluetec GL. My hook up procedure is to put the trailer on the ball and connect everything but the WD bars and sway bar. I locate the nearest level area which is for me is the street, set the parking brake and park it. I then set my 4x4 blocks under the trailer jack, clip in my WD bars, then raise the rear end up were I can set the chains in my predetermined 6 links on the trailer tongue WD brackets, latch them over/down by hand and safety pin them, then lower the trailer. I do this with the truck running so it can automatically adjust to the weight. I use a Huskey WDH with a matching Sway Bar which if set tight on a very windy day can be noisy when moving through a parking lot to either park or fuel up. Most of the time I don't run it very tight as I get very little trailer sway. Even when passing or being passed by semi's. Easy solution to the low speed popping is just to pull over beforehand and loosen it a few turns. I use the WDH to move about 200lbs to the front of the truck. It pulls smooth and straight with 0 drama and gets 15-17 at 65-75 mph, total trailer weight is close 5000lbs. Only issue I've had was with the LED lights on the trailer making the truck think a rear light was out. Easy fix for me is a 7 pin plug-in adapter. The Tekonsha P3 brake controller was literally plug and play and works really well. Unhooking is simply done in reverse, set your brake, (level trailer it if needed) then chock your trailer tires. Put your blocks under the trailer jack then lift it to release WD bar tension. Remove the safety pins from WDH on trailer tongue brackets, flip hold down brackets to release chains, rotate the WD bars unclip them and remove. Disconnect your emergency trailer brake, your 7 pin plug, the safety chains. Lower it, until the back end is starting to go down, unpin your couplers safety hitch pin then raise coupler latch pull it back off the ball. Then raise trailer back up it till it clears the ball. Sometimes depending on location and inclination of trailer to truck it may need to be leveraged up with a prybar to help free the ball from the socket as not all RV spots are level, posting up at North Rim of the Grand Canyon come to mind lol yeah, that one was fun. Any questions, just ask.

 

Thanks for that information. Much appreciated.
Bob

 

I finally had a a chance to tow my travel trailer recently and as things turned out I didn't use any wd bars. The airmatic self leveled and the towing experience with the GL was flawless. So now that raises the question: as long as the dead weight on the ball stays within Mercedes specs are weight distribution bars actually needed?
Bob

 

A properly set up weight distribution hitch is relatively cheap insurance against weird things like odd road surfaces when cornering, accidentally improperly loaded trailer, emergency braking situations, and plenty of other circumstances that I'm not thinking of right now. Yes, it is a pain in the backside to 1)buy, 2) set up, 3) connect every darn time, 4) disconnect every darn time, etc. but it takes weight off the back wheels, puts weight back on the front wheels, and makes the towing experience that much easier and safer.
I have a WDH on both my Chevy 2500 and on my ML350BT and both my travel trailers are only about 18' long (a '15 Rpod and an '87 Kit Road Ranger). Don't leave home without using the WDH whether it is to the local woods or a 1000 mile destination.

Short answer: Needed? No. Advantageous? Absolutely.

 

I have always used a WD hitch set up as all my other tow vehicles I have had were non leveling suspension so using weight distribution is a given. This is my first vehicle with self leveling suspension so It will be a new learning curve. Might buy a new trailer next year as my current one no longer suits my needs and is starting to show its age (1996).
Bob