It is generally believed that the distance between the kingpin and front bulkhead of a 13.6m articulated trailer should be 1600mm. This measurement is not a legal requirement although it was derived to conform to the 2040mm swing clearance regulation.
Teardrop™ trailers have an aerodynamic overhang at the top of the front bulkhead and it could be assumed that this would extend beyond the legal 2040mm swing radius.
Recently, the use of large radius front corner pillars has become more prevalent and their use generates an opportunity to increase the neck length in comparison to a square cornered trailer, although this is rarely utilised. For the Teardrop™ design, DON-BUR does utilise the additional length afforded by the use of large radius cappings to extend the aerodynamic overhang while the chassis neck length has been reduced marginally to accommodate the Teardrop™ profile.
This current engineering adaptation maintains a comfortable 26 pallet internal aperture and ensures that Teardrop™ trailers conform to all legal requirements.