Dual Cam Setup

A light bulb just went off in my head:

Look at this photo from the Reese web site:




Note how the snap-up extends the entire height of the frame. That makes a lot of sense to me. the bottom of the snap-up is at a strong point on the frame, not one of the weakest.


Now this drawing of how these work on a 6" tube frame:





Is it reasonable to speculate that these snap-up brackets are simply not designed for 6" frames and that the original design took into account preventing stress on the middle of the frame and that somehow, with these larger frames, Reese may have simply dropped the ball?


[edit]
OK I found some pics (including my install instructions) with the snap up not reaching the bottom of the frame. I still don't understand how a huge portion of the load on the snap-up does not end up trying to fold the frame in though (without the bolt at the top).
[/edit]

buzzard616 wrote:
Having read the whole string I am concerned that NOBODY has suggested that many of your clearance and binding issues would be rectified by switching to a bent bar hitch for your deep TT frame.

Yes, that's true. However the biggest issue for me right now is that all binding/clearance issued were resolved and the dual cam setup still messed up my frame. Reese believes the system was installed correctly and seems to have no interest in helping out with the frame or in determining the real root cause of the failure.

I still feel that the margin for error that Reese has built into their system for protecting the frame is close to zero and it's not for a lack of alternative mounting configurations. I'd really like to see someone chime in with one of those fancy engineering modeling programs that show stress points, etc...

Having read the whole string I am concerned that NOBODY has suggested that many of your clearance and binding issues would be rectified by switching to a bent bar hitch for your deep TT frame.



The frame on the TT in the photo is nowhere near as deep as yours but you can see that there would be nothin' but air between the bars and the frame.

I'm hoping, that when I go back to setup with the snap ups properly attached, that I won't have a need for videoing anything!! I'm pretty confident that I won't have the problem again.

And, it had to be a much less severe problem than what you had occur with the accompanying more severe damage. Yours looks like a classic example of some interference with a hitch or DC part and the over-stressing of the components, in this case, your frame. I will say, that if I had been towing on a trip to the mountains on the roads and sites we visit, there may have been more severe damage. Nobody can be sure until it happens!!!

If you know someone with a GoPro camera and magnetic mount - or if you're willing to put a cell phone or small camera at risk with a creative taping job you can try to get a video of what's happening in turns. If it's making that much movement/racket I would think you could capture something....

I do exaggerate!! But it was enough of a bang or snap to shake the Ex, and send two Boxers riding in back into a frenzy on each turn. And the volume I'm sure made anybody around wonder what the heck was going on!!

My next step is to clean up the bars almost down to the metal on the wear surfaces, mount the hangers, and recheck all the settings. If there is still a solid binding and banging, you can bet the bars will come off after the first turn!!

TUCQUALA wrote:
Just for reference, my bars and head are new, the cams are old!! New parts against used parts?? Will see how they act with the paint wire brushed away.

I guess that could be. Popping in and out of the wear area from the old bars. That's still a pretty big event if the entire excursion is shaking like a pothole at 60 mph. If you had 1/2 cup of coffee in the cup holder would it shake enough to make a mess?

Just for reference, my bars and head are new, the cams are old!! New parts against used parts?? Will see how they act with the paint wire brushed away.

TUCQUALA wrote:

I have read other posts before that say "when in a turn all the WD lift is applied to one snap up" and I politely disagree! The bars have two almost equal bends, and when one is going forward, the other is moving back and has to be applying an almost equal force to its snap up. I would bet that if there were a method of measuring that force, the 2 would be very close.

When turning, for example testing for clearance, I have noticed that the inside bar rides back and becomes loose, hence my believing others when they say all the WD load transfers to the other bar.

If you look at the outside bar, it rides up on the cam. This must put more tension on the bar, but I can't say with certainty that it's taking all the load of both bars. I just assumed that the WD system is always taking up the same amt of tension and if one bar is loose and can be moved by hand that the other must be taking all the load. I have no proof that's the case and I guess it's possible that something else is happening.

TUCQUALA wrote:

Just another thought, if there weren't a space on the inside between the snap up and the frame, I believe that there would be almost no occurrences of bent snap ups and frames, with the possible exception of bar to head or bar to cam arm jamming. Maybe Cequent should make a different snap up for the common frame width on today's trailers, or some sort of filler to spread the load.

I think we are in agreement here. That would prevent the snap up from moving and if something out of the ordinary happens the pinch bolt wouldn't be able to dig in as far and the snap up wouldn't be able to lever over into the frame as much. I think adding a thick backer plate - or plates on both sides would produce the same result.

TUCQUALA wrote:

That is one reason I am leaning toward the new bar paint against a rough cam (and probably not the same wear area) causing the excessive forces when the snapping or banging occurred.

My stuff was all new too. The part in your thread that got my attention was the shaking of the tow vehicle. I've had some loud pops, but don't recall one ever fairly violently shaking the tow vehicle (Excursion).

Just finished commenting on my earlier post about my snap up problem. Thought I'd throw in a comment about your last post.

I have read other posts before that say "when in a turn all the WD lift is applied to one snap up" and I politely disagree! The bars have two almost equal bends, and when one is going forward, the other is moving back and has to be applying an almost equal force to its snap up. I would bet that if there were a method of measuring that force, the 2 would be very close.

Just another thought, if there weren't a space on the inside between the snap up and the frame, I believe that there would be almost no occurrences of bent snap ups and frames, with the possible exception of bar to head or bar to cam arm jamming. Maybe Cequent should make a different snap up for the common frame width on today's trailers, or some sort of filler to spread the load.

I never had any interference with the ball mount, or the cam arms on my old round bar assy like the trunnion type seem to have somewhat regularly. My coupler is bottom mounted, and there is mucho clearance. That is one reason I am leaning toward the new bar paint against a rough cam (and probably not the same wear area) causing the excessive forces when the snapping or banging occurred.

Again, just thinking and mumbling!!

Have a great week!


Gerry