The steering dolly trailer or steerable dolly trailer are the efficient supplementary trailer, which are widely used for long beam and heavy duty cargo when low bed trailers are not suitable to transport. meanwhile, with help of turntable(bolster), steering dolly trailer or steerable dolly trailer could make the transportation with minimum turning radius. They are also called precast concrete beam trailer or section trailer.
Weight distribution of semi low-bed trailer normally is half-half, 50% of total weight is on top of rear axles (rear axles could be up to 16 tires), other 50% is on top of prime mover. So, if cargo is too heavy, prime mover will be in overload condition. Then, steering dolly trailer or steerable dolly trailer are designed to bear more weight under king pin of gooseneck to relieve pressure on tractor, to make sure every part are in more safe condition during transport process.
The towing dolly can increase capacity of a single trailer and share the pressure from gooseneck. Two steerable dolly trailers can be used as a group to transport long cargo, such as precast concrete long beam. Putting turntables (bolsters) on top of dolly, it is the most economic and efficient way to transport long beam cargo. This method can get both high carrying capacity and small turning radius. For heavier long cargo, long beam trailer or hydraulic multi axle trailer could be used to transport it. Most of dollies adopt mechanical suspensions, if any, they can be replaced to air or hydraulic for different purposes.
Main Functions of Steerable Dolly Trailer:
Decrease turning radius
Increase carrying capacity
Features of Steering Dolly Trailer:
Normally the dolly has 1 axle to 3 axles.
Optional power pack make dolly manually steerable.
Chassis-dolly could be equipped with gooseneck to be used as a small semi-trailer
To get a full trailer, just connect flatbed-dolly with towing bar.