In a combination with more than one trailer, which wheels off-track the most during a turn?

49 CFR 383.115(c); AAMVA CDL Manual Section 6.1.6 "Turn Wide," Figure 6.3, p. 6-3

Knowing that the very last trailer cuts the tightest corner tells a driver exactly where to focus their mirror checks and space management when turning a triples rig — it's not the tractor or the first trailer that's at the highest risk of clipping a curb or object.