Is this a sign of chain wear?

[Stephen Clark]

I can see a gap between the links of my chain and the teeth of my chain
ring. Does this mean that the chain has stretched (through wearing) and I
need a new chain and (possible) freewheel?

Also my newish (fitted by LBS last November) chainring has some teeth which
are shorter than the others (in two sets, almots oppoiste each other on the
ring). The ring has the text "special teeth - profiles shifting" and "Dual
SIS shifting" on it. Are these shorter teeth in order?

[Pete Biggs]

Stephen Clark wrote:
> I can see a gap between the links of my chain and the teeth of my
> chain ring. Does this mean that the chain has stretched (through
> wearing) and I need a new chain and (possible) freewheel?

Possibly but measure a length of the chain to be sure. See
http://www.sheldonbrown.com/chains.html (scroll down)

There is a certain amount of give with new chains, though (when chain is
pulled away from chainring by hand).

> Also my newish (fitted by LBS last November) chainring has some teeth
> which are shorter than the others (in two sets, almots oppoiste each
> other on the ring). The ring has the text "special teeth - profiles
> shifting" and "Dual SIS shifting" on it. Are these shorter teeth in
> order?

Yes, I believe they help the chain shift down to the next smallest ring.

~PB

[Paul - xxx]

Stephen Clark composed the following;:
> I can see a gap between the links of my chain and the teeth of my
> chain ring. Does this mean that the chain has stretched (through
> wearing) and I need a new chain and (possible) freewheel?

Not necessarily, does the chain jump off the sprockets under heavy
pedalling, such as mashing up a steep hill.

If you do fit a new chain it is worth fitting a new freewheel at the
same time, and possibly at least one, maybe more, of the front rings,
depending upon which is most worn. Most are generally available
separately, unless it's a low-end set and then it's probably
cost-effective to swap the whole chainset anyway.

> Also my newish (fitted by LBS last November) chainring has some teeth
> which are shorter than the others (in two sets, almots oppoiste each
> other on the ring). The ring has the text "special teeth - profiles
> shifting" and "Dual SIS shifting" on it. Are these shorter teeth in
> order?

Yes, the shorter teeth are part of the indexing shift system and aid the
easy movement of the chain across the sprockets.

Without them the gear shift gets a little notchy, is a little louder and
can be less precise.

--
Paul ...
http://www.4x4prejudice.org/index.php
(8(!) Homer Rules ... ;)
"A tosser is a tosser, no matter what mode of transport they're using."

[Simon Brooke]

in message <1107703133.19990.0@damia.uk.clara.net>, Stephen Clark
('octopusuk@hotmail.com') wrote:

> I can see a gap between the links of my chain and the teeth of my
> chain ring. Does this mean that the chain has stretched (through
> wearing)

Yes.

> and I need a new chain and (possible) freewheel?

Yes.

> Also my newish (fitted by LBS last November) chainring has some teeth
> which are shorter than the others (in two sets, almots oppoiste each
> other on the ring). The ring has the text "special teeth - profiles
> shifting" and "Dual SIS shifting" on it. Are these shorter teeth in
> order?

Yes, but that doesn't mean your chainwheel is not also worn by running
with a worn chain. Changing chains early is a good plan because they're
relatively cheap and if you run them too long the stuff they can damage
is more expensive.

--
simon@jasmine.org.uk (Simon Brooke) http://www.jasmine.org.uk/~simon/

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