Dexter Torque Suspension

I think Dexter sway control works on the wheel's NOT having the problem so it can correct for the one/s which has the problem. Seems logical to me.

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...."Alternate side braking technology Next generation technology promptly detects trailer sway and responds by applying EITHER the left or right brakes dampening the sway much quicker than other systems that apply brakes on both sides at the same time."

The compressible rubber suspension system for trailers and caravans was invented in Pommyland in the late 1940's, by a bloke named Alex Moulton.

The original suspension is called Flexi-Tor, and it comprises a rubber-bonded axle/spindle inside a housing, which is bolted to the chassis or subframe.
The Flexi-Tor uses a removable swing arm, clamped onto splines on the axle.
Later, cheaper versions simply use a swing arm welded to the axle.

Alex Moulton biography

Moulton went on to be a consultant on the design of Alex Issigonis' Mini-Minor rubber suspension.

When Moultons patent expired on the Flexi-Tor, others copied the idea. The cheapest version merely consists of a square axle mounted diagonally in a square tube (SHS steel) housing, with four rods of longitudinal solid rubber filling the voids between axle and square tube housing.
These are the suspension units with the welded swing arm.

These units are made simply by pressing an axle into a housing whilst the rubber rods are held in place, and compressed a relatively small amount - enough to stop the axle from slipping out.

When in use on the road, the pivoting of the swing arm compresses the rubber rods even further, allowing a degree of oscillation.
As RMD says, these units are made for smooth roads, because the angle of articulation is relatively narrow, and quite limited in its arc.

I built a 2,200 litre tandem axle fuel trailer in the mid-1970's using this type of suspension unit.
The fuel trailer was used on mostly dirt roads and paddock work.

The rubber suspension units failed completely within about 20,000kms. The rubber rods flogged out until the axle came out - and those units that didn't fail completely in this manner, ended up with bent axles.

I scrapped the whole four rubber suspension units within a year, and installed a four-spring rocker suspension with lubed shackles and lubed rockers - which suspension is still running today, more than 30 years later (my nephew has inherited the fuel trailer!).

These rubber torsion suspension units are extremely limited in their capabilities, and they won't stand up to hard work.
There is apparently also a difference in build quality between the original Pommy Flexi-Tor units and Chinese-built versions.

Flexitor failure - motorbike sidecar

I also utilised a couple of 4,500 litre, 4-wheel, articulated fuel trailers, supplied by my fuel company.
One of these units was built with four high-capacity, original Flexi-Tor suspension units (the ones with the bonded rubber guts), and the other articulated trailer had four conventional springs.

Neither of the articulated fuel trailer units gave any suspension trouble, and I would put this down to the fact that the manufacturers used some seriously-heavily-rated springs and Flexi-Tor suspension units.

But neither of these articulated fuel trailers did big kms, they spent a lot of time sitting around on job sites and in paddocks, and most movements of them were over short distances.

Cheers, Ron.