Where should the heaviest trailer be placed in a doubles combination?

The heaviest trailer should always be placed in the front trailer position (directly behind the tractor). This arrangement gives the tractor the most authority over the heavier trailer through the fifth wheel, while the lighter trailer follows on the converter dolly. Putting a heavy trailer in the rear position creates a 'tail-wagging-the-dog' situation where the rear trailer's momentum can overpower the tractor's steering and braking. Many state and carrier rules prohibit a heavier rear trailer in doubles combinations. When loads are nearly equal, place them either way; when significantly different, heavier in front is mandatory.