Chain Saga

[bigjim]

Is it not worth checking the indexing first before any further outlay? If the indexing is way out it is my experience that the chain will skip on the cogs unless you have DT levers.

 

[gbb]

I spent most of my first year on the middle ring - what do you think of the wear on the image?
Reckon I should just replace the cassette and see?

That chainring does look worn and i'd have replaced it.
If you have a new one on, plus chain, replace cassette.

 

[gbb]

One more thing: it seems that replacing the chainrings is advisable too. How do I ID the individual chainrings on my crankset? https://goo.gl/5yQaG4\

:

If you wanted to replace the chainrings you need...

Outer chainring is 48tooth 104bcd.
Middle chainring is a 36tooth 104bcd.
Inner is a 26tooth 64 bcd.

Now whether you need Deore (HG-X) specific chainrings is another thing, i'll let someone else answer that. It may be a generic and probably cheaper chainring such as a dural will work fine but ive never done it so can't say.

 

[Yellow Saddle]

@Yellow Saddle chainring image judgement.

Only if they're worn. My (3) chainrings are originals with 30,000+km on them (anecdata - inner has 2,000 less, replaced for 2 x 1000km hilly rides) and I'm sure there will be others who can boast of their chainrings' extreme longevity.
Most bikes never need their chainrings replacing. It does depend on how you ride and whether you spend most of your time in the middle ring - which maybe you do.

If you are asking about the chainring in the photo directly above your post, it is worn beyond use.

 

[Gummo]

I'm going to replace the cassette. Also, having spotted what seems to be a great deal on my particular crankset - I'll replace that as well: https://goo.gl/azhWW9

 

[Ajax Bay]

a great deal on my particular crankset - I'll replace that as well

Make sure you salvage your new middle chainring - since you are in that most of the time, that will be the one that needs replacing - but years hence.

 

[Gummo]

Good thinking - that'll make its purchase worthwhile in light of the new crankset.

Thanks very much everyone, for your kind help and attention.