Dual Cam Setup

mrekim wrote:
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]

Hi mrekim,

Sorry I have been away a bit and a lot has gone on since. A few things, that sales literature from the Reese site is a demo model. That is a 3" wide A frame. They show up on pop ups... It is not a real TT A frame that we are using.

5", 6" 8" A frame rails will have the issue of the snap up being supported by the frame center. It is not the A frame width issue, My channel iron 6" A frame rail has zero issues supporting the load pressed against it. And the set screw will bit directly to the inside web of the C channel. However the snap up on 1,200# and above can still fail due to the top springing open.

By bolting the snap up on that bending action that you so very well show in your sketch is not allowed to start. The bolts if drilled at the top of the hole in the snap up prevents the downward force from springing open the top of the bracket and also prevents the bracket from starting to pivot outward to apply a point load to the bottom heel of the snap up putting a lot of pressure on thin tube frames.

The Reese snapup bracket is very simailr to a C clamp setup and not a really great one at that. Have you ever sprung a C clamp before using one too small for the weight it has pulling on it? Same thing happens with the snap up.

I'm going to dig for a pic for you to help show the moment arm load effect of the chain on the snap up. This may add some help to the good discussion ongoing. I'll be back in a bit.

Thanks

John

PS. thanks for passing on the comments from Reese on the discontinuing of the bent angle chain plate. Yup, I suspected that folks were putting it on backwards and then really creating a problem factored into the equation. Sort of like this. I helped another bud with his, he pulled out the self tapping screws in his tube frame going around a corner. And the chain plate being on wrong did not help it. He was also into a corner radius issue.


See the other side, look you can see the bottom is bent some even if this side is turned.


It is not always "obvious" to everyone which way things should be.