11T sprocket on HG50

[Hawk]

The current configuration I have on my hub is as follows:

http://techdocs.shimano.com/media/t...S/EV-CS-HG50-8-1858_v1_m56577569830608759.pdf and it's the W-group (12-25T)

I'm wanting to change the lowest 12T to an 11T. I've stupidly bought and received this http://www.petracycles.co.uk/sprocket-p-4967.html (I assumed this was compatible and didn't look it up properly....)


What I found was that I could in fact fit the 11T sprocket on the end of my cassette - but the lockring was too large, it would have interfered with the chain sitting in the teeth.

Is there compatible 11T sprocket or a compatible cassette with 11T?

The lockring attaches to my freehub. I believe I would need a smaller lockring to fit an 11T sprocket? Is there a smaller lockring that STILL fits in my freehub, or would I need a new (different size) freehub to make that work?

EDIT: I have a hyperglide-c (compact) body [http://sheldonbrown.com/gloss_ho-z.html#hyperdrivec]
I now suspect all I need is the correct 11T sprocket and a smaller lockring?

 

[RecordAceFromNew]

You can simply get any 11T Shimano compatible cassette lockring, many are available under a fiver.

 

[Hawk]

Any recommended particular places you can buy the *correct* 11T sprocket for an 8speed HG?

 

[TheDoctor]

I don't see what the problem is with the sprocket you bought. Your issue is that you need a 11T compatible lockring.

 

[Hawk]

Thanks, I think I will need that. As it turns out, the sprocket is a 7speed so appears to be too thick anyway..? I measured the thickness with a micrometer

 

[RecordAceFromNew]

The difference in thickness between 7 and 8 speed 11T sprockets is merely 0.2mm, certainly well within rear mech adjustment and functional tolerance. If I were you I would use it.

 

[Hawk]

The difference in thickness between 7 and 8 speed 11T sprockets is merely 0.2mm, certainly well within rear mech adjustment and functional tolerance. If I were you I would use it.

Thanks.

Would the lock ring still be able to hold it safely though? The thread on the lockring I currently have is only maybe 1mm long (going from memory here). If my cassette is 0.2mm further out than it should be then I guess the thread overlap between lockring and hub would reduce, possibly substantially?

 

[RecordAceFromNew]

There should be 3 or 4mm of thread of roughly 1mm pitch.