Installation of Castle Nut On Hub

Updated 04/15/2026 | Published 04/08/2026

Question:

Hello. Is there a recommended torque for the hub axle castle nut before aligning for cotter pin?

asked by: Curt

Expert Reply:

Hey Curt! There isn’t a specific torque spec for the castle nut since it’s used to set the bearing preload rather than being torqued to a fixed value. What you’ll want to do is tighten the nut while rotating the hub to fully seat the bearings, then back the nut off. After that, re-tighten it just until it’s snug, and then loosen it slightly as needed to line up the cotter pin.

The goal is to have the hub spin freely with no play. If the nut is too tight it can cause the bearings to overheat, and if it’s too loose you may notice some wobble. Once you have the cotter pin installed you should be good to go.

What kind of trailer are you working on?

expert reply by: Robin H

Dan

4/15/2026

Hello Curt; I installed 4 hubs on my tandem trailer and did exactly as Robin instructed. Never encountered an issue and the wheels sit perfectly. This opinion is offered as a satisfied customer of e-trailer.