Hi Tom, Now play fair....Not every one has a used military truck and trailer thats built like bridge to use in hauling massive weights!!! ...LOL I"m using the term reverse torque weight as the weight is coming from a first class lever that rotates upon the axle. With out looking up the strength of a 1/4" chain, around 2800lbs, you gotta agree that is alot of upward pressure to deal with at 60mph. I had no load weight on this tri-axle flat deck, just the weight of the trailer, about 4000lbs. After finding that reverse torque could be applied to a tri-axle, it"s a design problem of tri-axle trailers, I did a couple experiments. One test I loaded the tongue with a additional approx 3000lbs so with the existing 1000lb tongue weight for about 4000lbs total tongue weight and the coupler would still apply upward reverse torque weight on the coupler when moved on slightly uneven ground. Most of the common surge brake couplers are rated at 2000lbs vertical loading. I have found one thats 3000lbs but very hard to acquire on the open market. I"m sure there"s heavier rated surge couplers but not a common item to find. So that would mean most of the common surge brake couplers are being used over there design limits. To resolve my tri-axle design problem, I"m going to use a tandum hanger system for two axles and a single independant axle hanger system for the third axle. Another design could be three independant axle hangers. It"s the tri-axle equalizing hanger design that is the problem. T_Bone
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