New Andersen WD hitch

Ron Gratz wrote:

CHD Dad wrote:
Hey guys - since we obviously have some engineers on here, has the coupler/latch issue ever been figured out? I know many pages back there was talk of contacting one of the big coupler manufacturers about it but I dont recall ever seeing a followup to that post. To me that is the single biggest flaw and/or safety issue with the Andersen design. Having the latch fail either while towing or when it comes time to just disconnect would be a major issue!

According to the VESC V-5 Regulation and the SAE J684 Standard -- the longitudinal test load for a ball and coupler is:

Class 3 -- 15,000# both forward and rearward

Class 4 -- 3 times trailer GVWR both forward and rearward

I don't know how much forward thrust against the ball will be produced by the Andersen system,
but it probably is considerably less than the VESC/SAE test specification.

Ron

OK, I am an engineer. And I've been reading this long thread recently with interest because I'm thinking of buying the Andersen WDH.

I've been thinking about the "reverse stress" concerns on the ball and coupler. Only time will tell, but maybe it's not such a big worry - here's why:

So for a Class 4 ball and coupler, don't the standards quoted above mean they must work up to 3G forces (3 times trailer GVWR)? And this means 3 G's both forward and backward (for accelerating and braking). Especially for extreme braking conditions where the trailer brakes totally fail and the truck brakes must stop the trailer through the ball and coupler. Probably the highest G Forces on the ball and coupler will be while braking with failed trailer brakes.

I doubt any TV can accelerate with a heavy trailer anywhere near 3G's - unless you had a jet engine or rocket or something as you would need 42,000 lbs of thrust from the TV to get 3Gs on a 14,000 lb rig: (6,000 lb TV + 8,000 lb TT) x 3 G's = 42,000 lbs. of thrust through the TV tires to the road to get 3Gs on the ball and coupler. A couple guys on the Tow Vehicles forum might have a mod for this.:C

So if you have a 8,000 lb GVWR trailer, the ball and coupler MUST be able to handle 24,000 lbs. of force in either direction (forward or reverse). I think the force on each chain from compressing the bushing for a heavy trailer can be around 1,000 pounds per chain.

This means 2,000 pounds of force (more or less) is applied to the coupler (1,000 lbs. per chain) that is rated for 24,000 pounds of force. This seems like a pretty good safety margin. But again, these are calculations (that I think I got right) - only time will tell for sure.

And over on the Airstream forum, some of them did have issues with their couplers failing with Andersen WDH. I have a theory for why they are seeing that. Basically Airstreams don't rust or rot - there are lots of 30 and 40 year old Airstreams out there with 30 and 40 year old couplers that are probably worn out. But the owners don't know about it till they use the Andersen Hitch.

Ed