Chain, cassette, chainring- what would you do?

For discussions about bikes and equipment.

Should I replace my middle chainring?

Poll ended at 6 Oct 2019, 7:30pm

Yes
13
87%
No
2
13%
 
Total votes: 15

Brucey
Posts: 36822
Joined: 4 Jan 2012, 6:25pm

Re: Chain, cassette, chainring- what would you do?

Postby Brucey » 5 Oct 2019, 3:20pm

NATURAL ANKLING wrote:Hi,
Brucey wrote:FWIW if I had replaced a chainring every time I Iet a chain go to 1% wear on it, I'd have bought several thousand pounds worth of new chainrings over the years, quite needlessly....

cheers

But we don't know what state of wear the chain ring is of the OP?....


yes, and it'll never be known if a new chain isn't tried on it....?

Simples really; If it runs rough with a new chein and you want it to be perfectly smooth, then replace it.

IMHO about 50% of chainring replacements are not strictly necessary; it is just assumed that the chainrings 'look worn' so they are replaced. Very often the wear is inconsequential and you would be surprised how often observed 'wear' turns out to be deliberate tooth shaping from new..... :roll:

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

keyboardmonkey
Posts: 664
Joined: 1 Dec 2009, 5:05pm
Location: Yorkshire

Re: Chain, cassette, chainring- what would you do?

Postby keyboardmonkey » 5 Oct 2019, 4:10pm

nigelnightmare wrote:As stated Get a new middle ring.
You already have the chain & cassette, so if the inner & outer rings are NOT worn too much you'll end up with a practically new drive train. 8)

It is your MAIN bike after all, spoil it and yourself. 8)

Go-on you know you want to. :wink:

>>>

geomannie wrote:Thanks everyone. My dithering is over & I have fitted a new chainring... Cheers

User avatar
The utility cyclist
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Location: The first garden city

Re: Chain, cassette, chainring- what would you do?

Postby The utility cyclist » 5 Oct 2019, 4:59pm

If it were me I'd continue riding it (I don't bother chain checking personally), you're going to have to buy - or have bought, the bits anyway but why bother fitting them all prematurely if the part worn components work just fine? But that's the tightwad in me, if it's a best bike then the components aren't cheap.

If it bothers you mentally to have the sub optimal/partly worn components, replace them, make sure to recycle the 'worn' bits and enjoy the ride.

MikeF
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Joined: 11 Nov 2012, 9:24am
Location: On the borders of the four South East Counties

Re: Chain, cassette, chainring- what would you do?

Postby MikeF » 5 Oct 2019, 9:32pm

geomannie wrote:........ Comparing the old with the new I am surprised just how much wear there was given that I have only done about 3,500miles on it but there you go.

:shock:
"It takes a genius to spot the obvious" - my old physics master

Brucey
Posts: 36822
Joined: 4 Jan 2012, 6:25pm

Re: Chain, cassette, chainring- what would you do?

Postby Brucey » 5 Oct 2019, 9:51pm

its worth making the point that not all wear on chainrings and sprockets is necessarily 'bad', i.e. it is possible to lose material whilst preserving the tooth shape well enough. Hence my suggestion that you should have a go with an old chainring and see how it runs.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

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geomannie
Posts: 547
Joined: 13 May 2009, 6:07pm

Re: Chain, cassette, chainring- what would you do?

Postby geomannie » 7 Oct 2019, 8:39pm

geomannie wrote:Thanks everyone. My dithering is over & I have fitted a new chainring. Comparing the old with the new I am surprised just how much wear there was given that I have only done about 3,500miles on it but there you go.


Hmm, I have a follow up to this.

I was surprised at how much wear there was on my 7075 Zicral alloy Stronglight chainring which I have replaced like for like (one of these https://www.spacycles.co.uk/m2b0s149p29 ... ddle-Inner). As it happens I have in my shed a similar-sized, rather worn Spa Cycles chainring in a nominally similar Zicral alloy (see https://www.spacycles.co.uk/m2b0s210p30 ... ddle-Inner).

The Spa Cycles ring had survived several chains whereas the Stronglight only the one chain. In the spirit of enquiry I did a little hardness test. Using a needle file, light pressure would make faint scratches on the Spa Cycles ring, but on the Stronglight with similar pressure I was actually raising small burrs. I know this isn't scientific but it seems to me that Stronglight Zicral is much softer than the Spa Cycles Zicral.

I was under the impression that 7075 Zicral was all the same, now I am not so sure. The Spa Cycles rings are also a fair bit cheaper at £19 than the Stronglight at £30 and I might look to these in the future.

(NB I only bought the Stronglight ring as it’s a Stronglight chainset and I wanted all the rings to look the same)
geomannie

Brucey
Posts: 36822
Joined: 4 Jan 2012, 6:25pm

Re: Chain, cassette, chainring- what would you do?

Postby Brucey » 8 Oct 2019, 12:08am

chainrings can be anodised or not, and this makes the surface hardness (scratch resistance) vary somewhat, almost independent of the material used.

FWIW Stronglight do seem to play fast and loose with their definitions of materials; they routinely describe 5083 as 'dural' for example. It is no such thing; 'dural' has a highly specific meaning which is an aluminium alloy which has copper as a primary alloying element. 5083 is in no way dural.

Is it possible that a company that describes their materials so badly actually uses the wrong materials altogether?

Zicral is meant to be a heat treated Al-Zn alloy (7075 in fact). Is it possible that they got the materials wrong, or that 'accidentally' the wrong chainrings ended up in the packets marked 'zicral' I wonder....?

The other thing that is worth bearing in mind is that if the 'one chain' has elongated more than the 'several chains' (on the other chainring) then more wear on that chainring is inevitable.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~