Jockey wheel range measured at the tow vehicle’s tongue upper surface – the mounting face for the DO35 pin:
Trailer Ball Height Range Standard and Low Jockey Wheel
|285/65R18 | 305/65R17|
|When Camper is Level||620mm||633mm||645mm|
|Tall (standard) Jockey Wheel A00067 at Maximum||876mm||889mm||901mm|
|Tall (standard) Jockey Wheel A00067 at Minimum||392mm||405mm||417mm|
|Low Jockey Wheel A00068 at Maximum||805mm||818mm||830mm|
|Low Jockey Wheel A00068 at Minimum||319mm||332mm||344mm|
These are the absolute maximum and minimums; bearing seat on the internal threaded shaft bottomed out on the jockey wheel’s internal tube as a minimum, with maximum being the thread would completely out of the inner tube.
It’d be best to take ~10mm off each extreme.