Dolly (trailer)
From Wikipedia, the free encyclopedia
A dolly that can be coupled to a truck or trailer so as to support a semi-trailer. The dolly is equipped with a fifth wheel to which the semi-trailer is coupled. This dolly needs its own rear lights and a registration plate. A tow dolly is little more than two wheels, an axle and a tow-hitch, used to tow a front-drive suspension car behind an RV or other larger vehicle.
There are two basic types of dolly:
- Convertor dolly, equipped with between one and three axles and designed to connect to a towbar on the rear of the truck or trailer in front. There are two variants of this:
- An a-dolly has a single drawbar with a centred coupling.
- A c-dolly has two separate couplings side-by-side.
- Low Loader dolly, equipped with a gooseneck type drawbar that attaches to the fifth-wheel coupling on the rear of a prime mover to distribute the mass on the fifth wheel on the dolly between the prime mover and the wheels of the dolly. Predominantly fitted with two axles.
[edit] Australia
Convertor dollies are used in road trains in Australia, most commonly with two or three axles and a hinged drawbar. They are also frequently referred to as road train dollies.
The C-dolly design is not allowed in Australia, as it prevents articulation between the dolly wheels and the axles of the truck or trailer in front of the dolly. Australian rules require articulation between axle groups.
Low-loader dollies are used with many low loaders to allow heavy cargo to be carried without overloading the wheels of the prime mover or low loader.