Double drop trailers are similar to Drop Deck, as they have a “gooseneck” which drops the trailer height to a lower level behind the tractor. What makes them different than a drop deck is they also drop below the trailer axles, not just the truck axles. This creates a “well” between the gooseneck and the first trailer axle. Typically, the deck height in the well area ranges between 18” and 24” depending upon the concentrated load capacity. However, it also significantly shortens the loadable deck length on a double drop trailer. It is common for a 48’ double drop trailer to have 29’ 6” deck length in the well.
Double drop trailers traditionally come in two types. They are fixed neck double drop and removable gooseneck double drop (RGN) trailers. As the names suggests, the fixed neck double drop has a gooseneck that is permanently attached to the well of the trailer while the RGN’s neck can be removed.
Double drop trailers are made of steel, aluminum or a combination of both steel and aluminum. They are generally between 48’ and 53’ in length and 96” to 102” in width. Because of the short well length of 29’6” Extendible double drops are popular options. An extendible 48’ double drop trailer, in the closed position, could be extended to 66’ 1” in the open position which would increase the well area from 29’6” to 47’1”.
The Black Gold™ Fixed Neck Double Drop is an all steel based lowbed trailer with a non-removable neck. Like all other Doonan products various flange and web thicknesses control the trailer’s capacity. See the typical trailer specifications by selecting the hyperlink above.
The Platinum™ or Diamond™ Fixed Neck Double Drop is an steel main beam based lowbed trailer with a non-removable neck. The Diamond™ has aluminum side rails and steel cross-members, where the Platinum™ has both aluminum side rails and aluminum cross members.
Chaparral II™ Fixed Neck Double Drop is an aluminum main beam based lowbed trailer. Due to the shallow depth aluminum construction it has a very limited beam capacity and GVWR.