Which trailer should be coupled behind the tractor when pulling two trailers?

When pulling two trailers, the lightest trailer should be coupled behind the tractor. This practice is important for several reasons related to stability, maneuverability, and safety.

By placing the lighter trailer in the rear, it helps to ensure that the weight distribution is better balanced over the tractor's axles, which contributes to improved control and reduces the risk of the trailers swaying or flipping. A heavy trailer in the rear can shift weight forward, making it more difficult to steer and increasing the risk of jackknifing. Additionally, lighter trailers tend to have more flexibility in terms of movement, which can aid in navigating turns and tight spaces.

This consideration for weight distribution and stability is critical for maintaining safe driving practices in a combination vehicle setup. Thus, coupling the lightest trailer at the rear is the recommended practice to promote safety and ease of handling while on the road.