Mercedes R320 CDI towing 31' '79 Excella

[cameront120]

Great news. Looking forward to seeing how it all works out for you.

[Tuco]

This is such a great idea it might be good for us "live axle" types. So following the procedure to reinforce the hitch and promote WD, we should weld a reinforcement bar from the receiver shank to the bottom of the differential. What could possibly go wrong?

[Road Ruler]

Originally Posted by trekerboy

Well, I've made an appointment with Can Am RV in London, Ontario CA to get the hitch and related equipment installed. I'll post pictures and let y'all know how it goes!

Sounds good tb. Get it done right the first time and enjoy the drive.

[cameront120]

Originally Posted by Tuco

This is such a great idea it might be good for us "live axle" types. So following the procedure to reinforce the hitch and promote WD, we should weld a reinforcement bar from the receiver shank to the bottom of the differential. What could possibly go wrong?

Now you're just trolling.

[Andrew T]

This is such a great idea it might be good for us "live axle" types. So following the procedure to reinforce the hitch and promote WD, we should weld a reinforcement bar from the receiver shank to the bottom of the differential. What could possibly go wrong?

Showing my age here but this has actually already been done. In the 60's a common hitch was the "Axle Hitch". It was a Y shape yoke that clamped onto the rear axle of the tow vehicle and then had some chains bolted to the rear bumper to keep it from falling down at the rear. The torsion bars held it up when you were towing. They were popular with rental companies etc. because you could install one in minutes. I never towed with one we always removed them when a customer came in with one.

Though I had people tell me they worked better than you would think. I never heard of any falling off but the manufactures said they would void the rear axle warranty if one was used. They dented up the bottom of the bumper pretty good.

Andrew T

[Andrew T]

Here is a typical Live Axle reinforcement with a spare tire below. The silver part is added.

[Tuco]

Originally Posted by Andrew T

This is such a great idea it might be good for us "live axle" types. So following the procedure to reinforce the hitch and promote WD, we should weld a reinforcement bar from the receiver shank to the bottom of the differential. What could possibly go wrong?

Showing my age here but this has actually already been done. In the 60's a common hitch was the "Axle Hitch". It was a Y shape yoke that clamped onto the rear axle of the tow vehicle and then had some chains bolted to the rear bumper to keep it from falling down at the rear. The torsion bars held it up when you were towing. They were popular with rental companies etc. because you could install one in minutes. I never towed with one we always removed them when a customer came in with one.

Though I had people tell me they worked better than you would think. I never heard of any falling off but the manufactures said they would void the rear axle warranty if one was used. They dented up the bottom of the bumper pretty good.

Andrew T

Thanks for posting this Andy. From the picture in the next post the reinforcement is attached to the frame which is what I would expect. I did an internet search for "Axle Hitch" but could only find pictures of ones designed for Quads, Bikes and Motorcycles. Could this type of hitch have gone by another name? I would love to see an example of this. On a side note, I really couldn't believe what people have done to overcome towing obstacles. Some of the images were just mind blowing.

[Road Ruler]

Originally Posted by Andrew T

[I]
Showing my age here but this has actually already been done. In the 60's a common hitch was the "Axle Hitch".
Andrew T

Back in the early 60's I recall the "Axle Hitch" as well. As a kid I remember my dad talking about them to customers but suggested they be avoided. Instead he sent folks to a reputable welding shop that did a good job of welding on a hitch.

[trekerboy]

Today is the day! Our R320 is at Andy's shoppe for the hitch install! They said there's the possibility it might not get done by the end of the day which I'm hoping isn't the case since we made a special trip and hotel stay to get this done. Nonetheless, walking around their facility and seeing other vehicles they've done I'm excited to have them working on it!

BTW, met Andy in person; couldn't have been a nicer, more knowledgeable guy!

[trekerboy]

It's done!




Can't say enough good things about Can Am and the work they did on the hitch. Thanks To Andy and your team!

[cameront120]

How does it handle?

[trekerboy]

Originally Posted by cameront120

How does it handle?

Good question. I haven't tried it with the trailer attached yet. I need to install the sway bar connectors to the trailer A-frame, then I'll give it a whirl.

[trekerboy]

Originally Posted by cameront120

How does it handle?

Just drove the rig "for real" for the 1st time taking it to a leak testing appointment (see this thread)... It was the absolute worst possible day to do a 1st run... 40 mph winds, raining cats and dogs. Horrible driving conditions.

All that being said, I was really happy with the R320's ability to handle this trailer in combination with the hitch installed by Can-Am RV. Don't get me wrong, you definitely know you're pulling a 31' trailer, but there was no issues with handling, accelerating or stopping. I even had to make one emergency stop (white-knuckled) and it stopped straight and quickly.

As a result of my 1st real-world towing experience with this setup I do think that I have some adjustment to do on my Weight Distribution bars...



I tried it on the 1st and 2nd chain rings but I might go to the 3rd ring or maybe use some bolts to do half a ring between the 2nd and 3rd. It's hard to adjust the WD setup because the vehicle has self-leveling rear air suspension, so really I'm using a "rule of thumb" that the front of the vehicle should measure as somewhere between 1/2 and 3/4 of an inch lower when the WD is applied. Nonetheless, everything is pretty level when it's all hooked up and configured properly so it's just fine-tuning at this point.

[cameront120]

At least you know how it handles in inclement weather!

[Knuff]

Our Cayenne and the trailer are pretty much a straight line when self leveling is active. I hitch up at the correct ("low") height setting of the suspension (but I turn off the self leveling because it tries to "fight back" during hitching). I also just switched from the first chain ring (actually it was minus half a ring using a bolt) to the second ring. It took 15K miles of wear and tear to the WD chains and bars that made this necessary. Our 25FB is completely straight this way.

BTW, I would try to find an "independent" hook for your emergency brake chain. Someone once told me that it is not a good idea to connect it to the hitch connector - in case the whole thing fails (falls off), your trailer's brakes would not be activated. The person who pointed this out to me said that he learned this the hard way (and actually with his truck's hitch connector, so this is not an SUV thing).

BTW#2: She is a beauty!!!

[trekerboy]

An update for those following this topic. We've done a few "test" tows just to get a handle on the rig and adjust the hitch. Handles great, especially once the WD hitch was fine tuned!

Normal MPG at 55 mph: 28-30.

MPG while towing our 31' AS: 13-16.

[trekerboy]

Just returned from our 1st "Big" trip and the R320 CDI performed really well towing our 31' AS. Some stats from the trip computer:

Total Miles: about 4600
Average MPG: 14.5
Hours Driving: 111

I had to add oil at one point (evidently diesels drink oil!) but other than that we had no issues. We encountered some steep grades while driving in and through the mountains around Banff, and while I did have to put the accelerator to the floor to maintain 55 mph up a hill once or twice there was never a point where I felt there just simply wasn't enough power to climb a hill we needed to climb.

One interesting thing of note... while my wife was towing through Montana a big truck passed us from behind and the trailer began to sway (very scary experience for her)... I was sitting in the front passenger seat coaching her through the "oh my gosh, oh my gosh, what do I do? what do I do!?" panic when all the sudden the vehicle's Electronic Stability Control (ESC) kicked in and IMMEDIATELY killed the sway/oscillation. I knew the vehicle would correct excessive yaw rates in normal driving conditions (without a trailer attached), but I had no idea that this function would also effectively kill trailer sway. A really nice and unexpected perk.

[Andrew T]

Glad to hear you had a good trip.

A truck passing should never cause sway so there is something out a little in the hitch set up. Likely you are carrying a little to much weight on the rear air suspension so you need to pull the torsion bars up a little tighter. If you were still on the same setting as you were when you left on the trip they would have worked in 2/3's of a link or so during the drive.

The good thing is your wife did not try and do anything it will take care of itself if you let it.

If you are heading by our way I would be glad to check it for you.

Andrew T

[trekerboy]

Originally Posted by Andrew T

Likely you are carrying a little too much weight on the rear air suspension so you need to pull the torsion bars up a little tighter.

Thanks for the tip Andy; we are going to stop by your place in the near future to get everything dialed in.

I thought that Trailer-Sway was an indication of not enough weight on the hitch? Not too much weight... In our case, after the sway event we pulled over, tightened the sway bars and put some more weight in the front of the AS. Seemed to help, but because we didn't make those two adjustments independently it's hard to tell which one actually "fixed it".

[trekerboy]

I've been meaning to post what the class 3 hitch hardware looks like underneath our R320 for a while, but haven't had the opportunity to take the pictures until recently. For those who are interested how this kind of hardware is installed on an R-Class Mercedes....