DOT regulation for trailer connection air transfer is 1/2 inch inside diameter. The coiled plastic hose is about 5/8 inches in diameter. The rubber ones are about 3/4 to 13/16 inch. Electric lines are around 3/4 of an inch. Our dump trailers use 1 inch ID hydraulic lines that are around 1 1/2 inch outside.
I almost forgot about our powder trailers. The tractors that pull them have a hydraulic driven rotary screw air compressor for unloading the fly ash and cement powder. One is mounted on the deck just behind the cab in a box with a large air cleaner on top.We also have a driver that takes his mountain bike and straps it to the deck so he can ride around when getting loaded and unloading.
There could be any number of things mounted in the open spaces such as headache racks, tool boxes, generators for sleeper power instead of idling the main engine, pumps, spare tires, collapsible cranes, and other equipment. Most larger fleets are looking for increased fuel mileage and decreasing the space between tractor cab and trailer. They are either using fairing and flexible panels or buying shorter tractors. Then there are the hard core roadies with the giant houses (sleeper). They will have water tanks for the kitchen and bathroom with shower, heaters and hot water, and I have seen one with a gas fire place.
Pete
I pray every day I break even, Cause I can really use the money!
I started with nothing and still have most of it left!
