TD-X for distribution transport

TD-X Mechanical Steering System

The TD-X steering arrangement is a mechanical system which is used primarily in distribution transport. This system steers the front and rear axle of a 3-axle trailer, with the front axle counter steering.

The TD-X makes it possible to increase the axle distance of a 3-axle trailer so the driven axle of the tractor will not be overloaded even when the semi-trailer is only partially loaded (in the correct vehicle configuration). Due to the greater axle spacing, the axles must be steered to prevent increased dragging of the tires on the road surface. Use of the TD-X results in a great reduction of tire wear and fuel costs.

Savings on

  • Tyre wear
  • Fuel consumption
  • Time, through better manoeuvrability 
  • Vehicle maintenance
  • Vehicle damage

Steering principle

While making a turn, the movement between the truck and trailer is transmitted by the fifth wheel plate, locked into the fifth wheel coupling by the steering wedge. The steering bar transmits this steering motion directly and without any play to a transfer lever. From the transfer lever, steering rods steer the axle mounting frames of the front and rear axles of the trailer. 

The front axle of the trailer steers in the same direction as the truck, the rear axle of the trailer steers in the opposite direction.

TD-X for distribution transport


  • A TD-X system enables you to steer the front and rear axle of a three or four axle trailer, with the rear axle counter steering.
  • RDW test report according EEC guideline (70/311) for most common TD-X configurations available at request (no. 56210101).
  • Special TRIDEC spline bolts used for most bolt connections. No loosening of bolts and re-tightening not necessary.  
  • Gross weight: 700-860 kg. Net weight of steering system is reduced due to the replacement of a conventional rubbing plate with the TRIDEC unit and modifications to rear of chassis to accommodate the turntable.
  • Steering angles between 13 and 23º.
  • Components: fifth wheel unit, steering bar, transfer lever, steering rods, axle mounting frames.