Worn rear axle
 

Hello,

I just recently overhauled my rear hub, an '03 Deore. While disassembling, I noticed that the threads on the axle, near the middle of the hub, have been worn down. The axle seems to be straight.

1. Should I replace the axle, or is this normal?

2. How could this happen?

-- Sean

Depends.

If you are talking about the actual middle of the axle, it was probably never even threaded. Don't worry about it.

If you are talking about the areas where the cones and locknuts reside, you need to replace the axle or you will never get the cone adjustment to stay tight. Be sure to get an axle that's exactly the same length as your current one.

It is in the center, and it appears that the area was threaded at one time, but the threads are worn down.

The center of the axle does not touch anything. Forget about it.

I wouldn't be so sure the axle is straight. I just overhauled my '01 Deore today and noticed the same thing though not as extreme as you indicate. The axle appeared straight, but holding it up to a straight edge in about 10 different positions revealed the axle was indeed bent be it ever so slightly. It was really noticeable when I tried to reuse my old QR and had trouble getting it in the new axle.

I'd have to agree. Another way to check is to roll the bare axle on a flat floor (much like you'd check a pool cue). If it's bent you'll know right away.

A lot of OEM axle shafts have threads that are rolled rather than cut and often the center portion of the axle doesn't have threads. Because the threads are rolled the axle diameter will be slightly smaller in the center than over the major diameter of the threads.