A towed agricultural implement including one or more processing units each supported on a chassis 2 is disclosed, in which the or each chassis supports the or one of the processing units on a central axis, the chassis being provided with a left hand side wheel assembly supporting structure 40 and a right hand side wheel assembly supporting structure 40, free ends of the wheel assembly supporting structures 40 being provided with wheel assemblies 38, each wheel assembly comprising a wheel 38 mounted on a wheel mounting 50, and the wheel mounting 50 being rotatable about an inclined axis and the wheel 30 being rotatable about a horizontal axis. The wheel assembly supporting structures 40 and the wheel mountings 50 are adapted to allow limited relative movement of each wheel mounting 50 with respect to the wheel assembly supporting structures 40 which enables greater control when the towed agricultural implement is towed about a corner.
