Take the 2-minute tour ×  I have a Shimano Altus 8-speed on my
hybrid/commuter bike. I have to put in a new cassette and a new
chain as well and looking at the teeth of the largest chainring
cog in the front, it looks like the teeth are pretty worn as
well.  I expected the chainrings to be replaceable individually
but was puzzled to see that they are one solid unit. It kind of
looks like a chainset but the pedal part seems so be attached by
a screw and does not appear to be part of the chainring-set.
The largest cog has 48 teeth and has 4 extra holes to attach a
chain protector.  Does anyone know the name of the part and a
supplier in the UK?  Would it be advisable to invest in a
chainset where I can replace individual cogs? What would be a
possible part combination?  enter image description here
share|improve this question Shimano are generally pretty good
for publishing their tech docs, and there is a whole page on
Altus at techdocs.shimano.com/techdocs/…. However it doesn't
appear to have details on the