The maximum rate of axonal transport is:

AXONAL TRANSPORT​ The apparatus for protein synthesis in neurons is located primarily in the soma, with transport of proteins and polypeptides to the axonal ending by axoplasmic flow. Thus, the cell body maintains the functional and anatomic integrity of the axon. Orthograde transport occurs along microtubules located along the length​ of the axon; it requires two molecular motors, dynein and kinesin. Orthograde transport moves from the cell body toward the axon terminals. It has both fast and slow components, fast axonal transport occurs at about 400 mm/day, and slow axonal transport occurs at 0.5–10 mm/day. Retrograde transport from the nerve ending to the cell body occurs at about 200 mm/day.   Reference: Ganong’s Review of Medical Physiology 26th ed pdf no 231