Is this a lockring washer?

[Chrissymx]

I have stripped my 105 cassette to clean and move onto my new wheels :-)

I'm left with this at the end. A search on the net says that its a lockring washer.

But i'm a bit unsure as the lockring and the last ring on the cassette have little teeth that seem to lock together. Surely if i put this under the lockring these teeth arnt going to going to do anything anymore.

Thanks

Chris

 

[SteelUn]

It goes between the hub and the largest sprocket.

 

[Gary E]

As SteelUn says. Looks like that could be number 13:

 

[PpPete]

If you need it on the new wheels it goes behind the biggest sprocket, but you may not need it.
Freehubs which are 8/9/10 speed compatible need the spacer behind 10 speed cassettes (which are, illogically, very slightly narrower than 9 speed cassettes)

 

[Chrissymx]

Thanks all

I put it on the new wheels today and all seems ok. Not been out yet though due to the rain :-(

Chris