A lowboy (low loader in British English, low-bed in western Canada and South Africa or float in Australia) is a semi-trailer with two drops in deck height: one right after the gooseneck and one right before the wheels. This allows the deck to be extremely low compared with other trailers. It offers the ability to carry legal loads up to 12 ft (3.66 m) tall, which other trailers cannot. Lowboys are used to haul heavy equipment such as bulldozers, industrial equipment etc.
Lowbed trailer features include:
Spring ride: lowest cost; however, it has a rougher ride and adds more stress to the trailer
Air-ride: very smooth ride, adding to the life of the trailer frame. Air rides can also be adjusted for a higher or lower deck height.
Hydraulic suspension: an oil-filled system, allowing wide variation of axle movement
Independent suspension: a double wishbone, hydraulic suspension, which offers more stability, greater steering angle and more travel
Main structural steel type: mill rolled beams save money; although being around 4,000–6,000 lb (1,814–2,722 kg) heavier, they also reverse camber after a few years due to the much-lower strength of the main beams.
T1 or A514 beams save weight and allow more versatile engineering of the trailer; they are cut to the highest-strength shape possible and welded together.