Hitch failure on a Diamond C FMAX 212

[nisaacs]

Hitch failure on a Diamond C FMAX 212, GVW 25.900k I think. I think the hitch is rated 30k, based on their web site. You can see it has been broken for a long time with the wear marks. Crazy it broke in the first place.

 

[groundcover]

Wow, catastrophic failure! That could have been life threatening!

 

[ArlyA]

That is in an interesting break. Your photo shows the telescoping part that broke off in the inside.

 

[ruffdog]

It broke right where the set-screw tightened into it....interesting. It looks like the screw focused the stress at that point.

 

[nisaacs]

It broke right where the set-screw tightened into it....interesting. It looks like the screw focused the stress at that point.

Armchair quarterbacking, I agree If they are too tight, they can distort the tube. I think the recommendation is about 90 lbs tq.

However, there seem to be several of these break, from what I am hearing. China steel maybe?

 

[nyone]

I think if a set screw made that fail they used the wrong thickness of steel.

 

[Whitbread]

When i ordered my diamond c 212, I purposely upgraded to the square coupler tube. No issues and I run heavy regularly.

Looking at it from an engineering point of view, if the inner tube failed first, the outer tube would absolutely fail in rapid succession. DC doesn't build the inner tube (bulldog?) and the outer tube certainly isn't designed to operate alone. Crappy regardless and I hope your insurance covers the new trailer!

 

[nisaacs]

When i ordered my diamond c 212, I purposely upgraded to the square coupler tube. No issues and I run heavy regularly.

Looking at it from an engineering point of view, if the inner tube failed first, the outer tube would absolutely fail in rapid succession. DC doesn't build the inner tube (bulldog?) and the outer tube certainly isn't designed to operate alone. Crappy regardless and I hope your insurance covers the new trailer!View attachment 819839

Nice trailer, and I really like those log bunks.

 

[Hay Dude]

When i ordered my diamond c 212, I purposely upgraded to the square coupler tube. No issues and I run heavy regularly.

Looking at it from an engineering point of view, if the inner tube failed first, the outer tube would absolutely fail in rapid succession. DC doesn't build the inner tube (bulldog?) and the outer tube certainly isn't designed to operate alone. Crappy regardless and I hope your insurance covers the new trailer!View attachment 819839

I also ordered the square tube hitch and also the 3” ball. I try to overbuild everything I possibly can. Costs more, but catastrophic failures are (hopefully) not on my bucket list.

 

[nisaacs]

I also ordered the square tube hitch and also the 3” ball. I try to overbuild everything I possibly can. Costs more, but catastrophic failures are (hopefully) not on my bucket list.


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Going off memory here but I think your trailer is rated 38k gvw. So, 40k square hitch and 3" ball would be standard equipment. Even more so, with a deck on the neck. I have not seen a round hitch go over 30k gvw. However, they do make lighter duty square hitches for lighter duty gvw trailers.