Anyone know if someone sells a steel 31 spline bearing insert? I’ve replaced a lot of aluminum ones...

Is the axle worn? This could cause the problem.
Are you getting the axle nut tight?
If you have a steel splined bearing insert, then you will definitely where the axle splines.
Which is cheaper to replace, the axle or the alum splined insert?

Basically new axle. Not the spline’s wearing but the flat face between insert n spacers mushroom. Never had wheel come loose but maybe it’s needs tighter...

I’ll check, I had some in stock.