Where did my cassette spacer go?!?

[ohnovino]

Long story short: I traced a rattle on my hybrid to the cassette being loose, and when tightening the lockring made no difference I tried adding an improvised spacer (rubber band!) and it's fine now.

A bit of googling shows this is a common problem people have when fitting a new cassette, and in my case I need the extra 1mm spacer for an 11T cassette to fit the hub. But I wasn't fitting a new cassette. I've had it for thousands of miles, and I've never taken it off once.

So how can an spacer vanish? It can't just fall off, as it's stuck between the inside edge of the hub and the cassette. Even if it broke it should still stay in place unless it completely disintegrated, shouldn't it?

I'm at a loss to explain this. Has anyone else lost a spacer in this way?

 

[Maz]

You mean these things? They do sometimes shatter in situ if you're unlucky (speaking from experience).
They are not strong as they are not load-bearing...I ordered a new cassette once and one of these rings was shattered into several pieces on arrival. I'm guessing it was manhandled (dropped) in transit.

 

[lpretro1]

At 1mm the spacer is very thin and yes they can wear through and then drop off. We have had several in our workshop over the years.

 

[ohnovino]

Well it's good to know I'm not just going mad!