I have a brand new hub assembly for Karavan trailer with a torsion axle. The assembly comes with everything between the spindle and the wheel (see attached). They are supposed to be a lifetime hub, but mine started failing after about two year.

Definitely a good idea to care spare you have this setup.

New from Karavan: $70 + Shipping

Sale price: 40 + Shipping (or local pickup)

Hub.pdf