Dual Cam Setup

mrekim wrote:
But we may have one more puzzle piece to fit:

This is the other side of the frame. It didn't have the snap-up failure and there isn't a big dent from the snap up pinch bolt.

After the latest new discoveries I have a hypothesis to what "might" have contributed to this.

What we do know is the frame deflected inward permanently. We can see it. In order to bend inwards it "appears" the cam arm rotated CW as viewed from the front. This pic shows what I am referring to.


Now we just need to sort out what caused the cam arm to rotate enough to cause permanent deformation of the frame. When mrekim showed us this pic, it started the thinking process. Note: We can tell the mold that cast the arm on the left is slightly different on the cam outer boss area then the arm on the right. It also appears the cam does not extend as far from the threaded shaft. It might be a picture anomaly. Cannot confirm from this on pic. Do you have a top view looking straight down?


Reese upgrade the frame bracket. This is now the 3rd upgrade to the HP DC. Let's look back to the early days when the new HP DC came out to offer a different mounting than the older standard DC that used U bolts to hold the DC to the frame.

I bought my first HP DC in late 2003. It had been on the market for a few years by then. In late 2007 I bought another one. Across these years the HP DC remained unchanged. I want to point out the distance from the outside of the frame plate to the side of the 1st clevis plate. Also the bend radius of the frame plate.


This vintage frame bracket allowed the WD chain to hang a certain distance out from the frame. The distance from the outside of the frame plate to the 1st cam arm yoke clevis was set by the approx. 1/2" distance show in this pic.

In 2010 Reese upgraded the design. Believed to help some of the cam arm binding problems on some trailer A frames. The A frames with the ball coupler on top had the larger issues unless the owner did certain installation measures to prevent the cam arm binding in compound angle turns. In this design upgrade they changed the frame plate in addition to the cam arm. The frame plate bend radius increased where it contacts the edge of the frame. They also shifted over cam arm by approx 1/4". The cam arm yoke now mounts 3/4" from the outer edge of the frame plate.


In this 2010 vintage they also had a bent chain plate to help move the WD chain closer to the frame. Issues started to show up with larger frame plate radius where is could rock on the frame. Over time this could work loose the screws if the installer did not shim out the frame plate with washers like the channel iron frames need. And then the owner would inadvertently mount the chain plate backwards. It is not intuitive to all that pulling on the chain way off center is not a good thing.




mrekim reported in a call to Tech Support Reese has gone back to the straight plate as too many bent chain plates where getting installed wrong. Reese was trying to do a good thing by getting rid of some of the off center chain load with shifting over the cam arm and the bent chain plate. However it was not user "proof". I have no idea why they increased the frame plate bend radius.

Now in 2013 we have found another upgrade to help the off center chain pull. Or at least it is my opinion this is what they did it. The frame plate was changed again. They brought the smaller bend radius back of the year 2001 vintage and again moved the cam arm over another approx 1/4". This now is approx 1" from the outer side of the frame plate face.

Here is mrekim's frame bracket where I highlighted some features. The 1" is an estimated distance based on relation to the known 1/4" thick frame plate. It might be 7/8" or 1 1/8". Or my estimate is right on.


The smaller frame plate radius is positive move. Making attempts to help lessen the off center chain pull is a positive step as well. However I am not a fan of a 1 sided fillet weld in how they made the bracket.

So how does any of this relate to mrekim's bent in right side A frame? This side did not bend the snapup yet we have evidence the cam arm rotated enough to cause the frame to bend.

There are a few factors in this equation. Some are these 3. Their may well be more however these 3 come to the top of the list. Anyone with more, please add.

1. A new 2013 1" offset on the cam arm frame plate.
2. An 6" A Frame made from 11 gage tube steel on an 1,100# loaded TW which is very inline for the size of camper.

3. Another factor not yet discussed is hitching up. Mrekim when you hitch up do you flip the snap up's real easy either by your hand or gently pressure on the pipe OR do you pull full weight of the spring bar with the pipe to snap up? What do you do tongue jack during snapping up?

Before I go down the road of no. 1 and 2, need to know how number 3 is performed. Please give us the details on how you snap up?

Hope this helps

John

Totally understand the setup will affect the friction. I just am going with my experiences since the orig install in late 2004. I really never had any probs. Now the frame has dimples from 2 short, unfinished setup excursions (pardon the pun!!).

As to the cams, Mrekim, I have talked with the same rep at Cequent, and while he didn't offer to replace the cams, he did indicate that could happen. I was willing to see about thinning the bars at the cam end but at this point I am not sure if I will. I may call him back and push for newer cam assy's.

For now the trailer is in the back yard for the winter, and I am lazily looking for a pair of the proper 1000# bars so I can use my old head and cams and not worry if the 1200# setup will be too much and cause more damage.

I was, and still am, very pleased with the original setup whether I was using the 750's or the 1000's, but right now very leary of the new bars and head.

Will keep watching, and learning on this thread and any others.

TUCQUALA wrote:
As to overloading the bars, I am having difficulty understanding how you can overload a flexible bar and have the bars not want to turn. I ran my orig 750# round bars on my Jayco for about 2 yrs before going to the 1000# bars with no negatives with almost 900# of actual tongue weight. Yes, they were overloaded, and the combo felt soft, but they (or the 1000# bars) did not cause any damage to the DC parts or the trailer frame.

I have no idea. I just thought of it and threw it out there. :) That being said, even if you are using 750 lb bars with a 900 lb tongue weight, they could be set to transfer very little weight or a whole lot of weight, depends how you have it set up. The more weight you are trying to transfer, the more friction you have where the bars attach to the hitch head. The more friction you have, the less the bars want to rotate. Secondly, the heavier bars will flex less than lighter bars under the same load. When the heavier bars don't flex, something has to absorb the impacts from bumps.

TUCQUALA wrote:
I interpret Mrekim's past comments to indicate that he has only used the newer 1200# DC kit on this trailer since new, unless he is going to tow without the DC. Then he uses his 800# bars since he does not have to redo the chains!! He can verify yes or no.

Not swapping chains is part of it. Not using the heavier bar is part of it too. I'm trying to minimize bending snap ups and making the face of the A-Frame worse. It seemed like the lighter bars would be a better match to that end for the time being.

I've been moving the trailer around so the frame and DC setup can be inspected and don't want the people looking at it to have to mess around with the chains either.

I don't know if I would go on a camping trip set up this way. We're also monitoring the A frame with a GoPro camera and watching it in real time as we tote it around. That get's old after 30 or 40 minutes... and impossible in the dark.

TUCQUALA wrote:

Again, I feel that the new 1200# system I was sent by Cequent does not work with my earlier (gold) style DC, and I am kinda pissed at them for not considering that I have the narrower cams since they had copies of my orig purchases. I didn't see the differences until the first snap up bent, and I started researching the problem. My fault, yes, but still doesn't help with the problem!!!

I missed that, I stand corrected (and edited to show) in my statement above. Maybe that's one of the differences between the classic and the current version - the cam is wider to support larger bars. Did you call them and ask to have the cam arms or the entire DC system replaced?

I interpret Mrekim's past comments to indicate that he has only used the newer 1200# DC kit on this trailer since new, unless he is going to tow without the DC. Then he uses his 800# bars since he does not have to redo the chains!! He can verify yes or no.

As to overloading the bars, I am having difficulty understanding how you can overload a flexible bar and have the bars not want to turn. I ran my orig 750# round bars on my Jayco for about 2 yrs before going to the 1000# bars with no negatives with almost 900# of actual tongue weight. Yes, they were overloaded, and the combo felt soft, but they (or the 1000# bars) did not cause any damage to the DC parts or the trailer frame.

Again, I feel that the new 1200# system I was sent by Cequent does not work with my earlier (gold) style DC, and I am kinda pissed at them for not considering that I have the narrower cams since they had copies of my orig purchases. I didn't see the differences until the first snap up bent, and I started researching the problem. My fault, yes, but still doesn't help with the problem!!!

A comparison of Reese Dual Cam vs Equal-i-zer that may or may not be of value in the analysis.

For this Reese hitch, somehow the cam lobe is forced outward causing the frame to bend and possibly causing the snap bracket to bend.

For the Equal-i-zer hitch, whenever an L-Bracket is bent, it tends to bend inward. See note below about the pins.

The obvious looking factor is how the WD bar support is supported. For the Reese, the support comes from the outside of the cam and for the Equal-i-zer, the support comes from the inside of the L-Bracket.

Therefore, the cause of the failure or bending MAY be related to the side of the support the WD bar is supported on.

That being said, I have 2 scenario's:

1) It is possible that if the WD bars are not flexing under load, something has to give and the weakest link does. Cause can be too stiff of a WD bar or an overloaded WD bar or a combination of both (I believe the OP never had this happen with his lighter bars).

2) It is possible the WD bars when loaded with a heavy tongue weight (or if loaded too much or too heavy of a bar as explained in 1 above) do not want to turn because of the friction and therefore there is an extreme side force on the WD mounting points. The support for the mounting point acts as a lever and the weakest link bends.

Note: On my Equal-i-zer, the little pins that go around the WD bar and get secured to the L-Bracket do bend outward over time. I'm told this is normal. Because these little pins bend, it can only be related to the outward force from the bars during turns. So although the pins kind of look like an afterthought, outward and inward forces exist and can be extreme.

TUCQUALA wrote:
Looks to me, that Cequent has many redoes of the DC system, and some of us may be paying the price to try to mix them up!!!

I think for the DC as long as you don't start mixing and matching the frame bracket and cam arms you are not risking mismatched parts. Maybe the teardrop piece should be included in that - I'm not sure.

I looked on the Reese web site for part numbers to determine what changed vs what was just updated and didn't find much info.

There is the DC and DC Classic which I assume are somehow different enough that they have different part numbers. However I could not find cam arm part numbers for the current and Classic versions to compare(as an example).

[EDIT]
We know the cam width has changed over time too. So using new heavier bars with and older DC with the narrower cam could be a problem
[/EDIT]

Yes, the discovery continues!!!

Looks to me, that Cequent has many redoes of the DC system, and some of us may be paying the price to try to mix them up!!!

JBarca wrote:


Since you now have 2 complete DC kits from different revisions, If you lay just the cam arm and the black yoke on top of each other, no frame plate, are the arms/yokes different? Meaning one has an offset more than the other?

I can't do that. I snapped a bunch of photos last night when boxing up the old one to send back to Reese. They wanted to inspect the dual cam parts and snap ups to see what stresses they may have seen. I could not notice an offset difference, the new one seemed a tiny bit thicker in the arm and the collar.



Do these help:

JBarca wrote:

You also seem to have both the older snap up brackets and the new HD snap ups with the added gusset. If you look at the end view of them on the TT frame, does it appear the new HD bracket has the chain hook point where the chain will hang plumb closer to the A frame on the new HD bracket than the older style?

I put the old and HD snap ups next to each other. The seem to be the same except for the gusset.

It appears Reese has created a somewhat new frame bracket with this 2 piece welded design.

Now more questions...

Since you now have 2 complete DC kits from different revisions, If you lay just the cam arm and the black yoke on top of each other, no frame plate, are the arms/yokes different? Meaning one has an offset more than the other?

You also seem to have both the older snap up brackets and the new HD snap ups with the added gusset. If you look at the end view of them on the TT frame, does it appear the new HD bracket has the chain hook point where the chain will hang plumb closer to the A frame on the new HD bracket than the older style?

This one pic of yours having HD snap up on 1 side and the older one on the other side "seems" to show the chain would hang closer to the frame on the HD bracket. But this could be a photo illusion.


I have a "hunch" that Reese may have created that new 2 piece DC frame plate to shift the DC more under the frame to get the chain to hang more plumb and closer to the TT frame. I would "think" it would cost more money to make the 2 piece frame plate than the 1 piece. So the change appears to be intentional. They may have been trying to help the problem of bending snap up's with this tweak. It now comes back to the cam arm, if the cam arm and yokes are the same between the 2 vintages you have, then for sure the cam arm is moved under the frame more when using the 2 piece bracket.

The discovery continues...