You should check trailer height before connecting a converted dolly to a second or third trailer. The trailer height is right when:

Question

Accepted Answer

B: The trailer will be raised slightly when the converter dolly is backed under it.. The height of the trailer needs to be positioned so that the kingpin is slightly lower than the fifth wheel. When the converter dolly (or truck) is backed into it the trailer raises slightly on the fifth wheel.

You should check trailer height before connecting a converted dolly to a second or third trailer. The trailer height is right when:

New Jersey CDL Doubles/Triples Test Info