In many ways the PORT SM trailer is a culmination of the engineering that went into those two vehicles. Jerry's comprehension and appreciation of Citroen's intent and methods is clear. The trailer chassis is a self-supporting hollow structure. It incorporates four (4) independent trailing arms from the Citroen D-series station wagon (or ‘'Break'') model; along with their drum brakes. Of course the suspension is hydro pneumatic and self-levelling but it is also designed to adjust for laden or un-laden so that the ride is soft when the race SM is loaded, but it doesn't bounce down the highway when empty. Further, the ride height is adjustable from sitting on-the-ground for loading the car, to minimal clearance for on-the-highway, to extra ground clearance for driving in-and-out-of driveways (etc) to maximum height for changing-a-trailer tire, of course!
The suspension cylinders and spheres themselves are mounted in the compartment designed into the bed of the trailer to hold all the trailer mechanicals. But the ride height can be adjusted from inside the WORK SM via electric/ hydraulic switching; adapted from yet another Citroen model..
The PORT SM brake system, however, is unique. It is not electric (as commonly used in the US ) nor is it pneumatic (as is used in Europe ). Rather, the SM World design uses a weight (mounted on roller bearing (‘'wheels'') which is affected by deceleration to actuate a brake valve (adapted from the sm). And, to accommodate those situations when you might not want the trailer brakes applied (such as when backing up a hill) the weight/brake is deactivated by being held in place by an electro-magnet; which is switched on from inside the WORK SM(!).
At first sight, the appearance of the PORT SM trailer's mechanicals compartment is both astonishing and confounding. Then, if you are familiar with SM parts (or even with Citroen hydraulics) you begin to recognize some components. There is the 7-piston Citroen hydraulic pump; supplying pressure for suspension and braking. But, it is driven by a 12 volt DC electric motor(!) in order to be independent of a vehicle engine to power it.
Next you will notice a hydraulic pressure regulator & main accumulator… but, there are more hydraulic accumulators (or spheres)… a total of nine(9) to be exact; whose purpose/function will be further explained below.
Two(2) 12 volt batteries have been installed in-parallel to provide power for the hydraulic pump. In parallel because every part of the trailer is fail-saved. The batteries are kept charged by an additional alternator mounted in the WORK SM. It is actually mounted in the position where the original ( USA ) air pump was.
As for the nine(9)spheres, there is one main accumulator. There are two(2) brake accumulators (the 2 nd for fail-safe) there are six(6) suspension spheres: one-per-axle/wheel for when the RACE SM is on board(=4). The additional suspension spheres (one per side) are for increasing the ‘' cush '' when the trailer is un-laden; so it doesn't bounce down the road when there is no car atop it. These are added to the system by manual levers which are drawn when the car is off-loaded from the trailer. And of course, the suspension system must have an anti-roll bar and a height corrector to maintain any selected height. These are located toward the rear.
It is especially amusing to note that although Citroen-original parts were utilized throughout (from the hydraulic reservoir to such mundane components as relays, tubing, and clamps) the actual trailer itself was built from nothing. It had to be. Truly nothing existed that could be modified to work. The result reveals some enormous forethought and attention to detail. For instance, the ramps (those annoying appendages that always have to be dragged and put somewhere). Here they are hinged and merely tip-down to load; and tip-up to drive away. And, since it is only intended to carry (‘'port'') an SM, wheel pockets are sculpted into the bed to cradle it.
The trailer fenders are attached to the trailing arms and incorporate ducting to cool the drum brakes. Even the spare tire was planned for. It can be found in its special nest; which drops down from beneath the trailer. The list goes on to include winch pulleys, halogen back-up lights, auxiliary battery charging outlet, etc, etc, etc. plus, the whole is powder coated paint to match the SM Pick-up and Race Car.
And finally, this remarkable rig, on its ‘'maiden voyage'' drove from Coast-to-Coast ( California to Massachusetts ) and back flawlessly!