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 Post subject: chain ring wear
PostPosted: Thu Feb 21, 2013 3:51 pm 
Retro Guru
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Joined: Sat Apr 02, 2011 11:16 am
Posts: 799
Location: Camden, London
a picture is worth 1000 words, Shimano SG off 1991 marin

Image

Image

so questions, totally knackered or a little left ? why is wear so irregular ? is there an easy check for the chain (I don't have a specific chain wear tool) and this is off 7 speed and all the replacements I've seen are for 8/9 speed where I assume that the ring is slightly thinner to accomodate the narrower chain and hence less metal so wears quicker ? has anyone seen a good place for replacements ?

cheers,


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 Post subject: Re: chain ring wear
PostPosted: Thu Feb 21, 2013 3:56 pm 
Gold Trader / PoTM Winner
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Joined: Mon Aug 08, 2011 2:35 pm
Posts: 2786
As far as I can recall

1) The wear isnt irregular, the small teeth are to allow the chain to jump off when shifting
2) 7/8/9 speed should be interchangeable
3) There are details on the web about measuring chains with a ruler, to determine wear

4) Teeth profiles look OK to me


G


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 Post subject: Re: chain ring wear
PostPosted: Thu Feb 21, 2013 5:17 pm 
retrobike rider
retrobike rider
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Joined: Tue Mar 17, 2009 3:55 pm
Posts: 4309
Location: In trubble'fsumthin r'uther....North Warwickshire
thats not as bad as it seems!.......they really do 'all do that'.....the important wear is where the chain meets the teeth, 3 or 4mm down them.......does it run ok, or skip around under pedal pressure?....


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 Post subject: Re: chain ring wear
PostPosted: Thu Feb 21, 2013 5:23 pm 
retrobike rider / Gold Trader
retrobike rider / Gold Trader
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Joined: Sat Jun 20, 2009 3:45 pm
Posts: 5261
Location: Birmingham
as they have said, it looks fine and is meant to be like that, the teeth dont look very worn down or pointed or shark toothed to me.


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 Post subject: Re: chain ring wear
PostPosted: Thu Feb 21, 2013 7:32 pm 
Retro Guru
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Joined: Sat Apr 02, 2011 11:16 am
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Location: Camden, London
feetabix wrote:
.......does it run ok, or skip around under pedal pressure?....


it came off a project that the gears didn't work that well but that was a combination of all of maintenance or lack there of, dirt etc all over mechs and chain, so difficult to tell really, having cleaned gears etc and set up with new cables still skipped a bit so decided to clean rest and not take short cuts. With a different (but same type) chainset now seems to work ok so guess the proof would be to put this one back on and see how it goes, was just quite surprised by what I found having cleaned the rings and looking at condition.


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 Post subject: Re: chain ring wear
PostPosted: Thu Feb 21, 2013 7:48 pm 
King of the Skip Monkeys
King of the Skip Monkeys
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Joined: Wed Nov 07, 2007 4:34 pm
Posts: 26178
Location: Moomin Valley
As above, its a normal looking ring. The 'missing' teeth aid shifting.

Typical knackered rings:

Image

This sort of wear leads to 'chain suck'

Image

Brilliant!

Image


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 Post subject: Re: chain ring wear
PostPosted: Thu Feb 21, 2013 7:50 pm 
King of the Skip Monkeys
King of the Skip Monkeys
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Joined: Wed Nov 07, 2007 4:34 pm
Posts: 26178
Location: Moomin Valley
Sheldon browns input:

Image


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 Post subject: Re: chain ring wear
PostPosted: Thu Feb 21, 2013 8:18 pm 
Retro Guru
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Joined: Mon Mar 28, 2011 9:29 pm
Posts: 1877
Location: Somerset
unkleGsif wrote:
3) There are details on the web about measuring chains with a ruler, to determine wear

4) Teeth profiles look OK to me
G


1/2" per link, I'd change a chain on a cared for drive train at + 1/32" over 12" of chain. 1/16" + and over, over 12" of chain and the chain is very dead, possibly having caused damage to chainrings and cassette.

+1 To the OP's chainring looking fine.


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 Post subject: Re: chain ring wear
PostPosted: Thu Feb 21, 2013 11:15 pm 
Dirt Disciple

Joined: Sun May 06, 2012 7:25 pm
Posts: 43
Location: Ocala, Florida
New chains are inexpensive compared to expensive chainrings,and cassettes/freewheels. Replace the chain twice a year if you ride often in old blighty weather or yearly otherwise. The expensive bits will last MUCH longer!


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 Post subject: Re: chain ring wear
PostPosted: Fri Feb 22, 2013 12:19 am 
Retro Guru
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Joined: Sun Mar 14, 2010 2:33 am
Posts: 2929
Location: daaan saaaf
Quote:
Replace the chain twice a year if you ride often in old blighty weather or yearly otherwise.


Or buy a chain checker: http://www.parker-international.co.uk/18632/Park-Tool-CC3-2-Chain-Checker-Tool.html

I replace mine as soon as it gets to .75% elongated. I also shuffle my chains from my "best" bike with the most expensive cassette and chainrings to my other biked with cheaper components. So, which ever bike has a worn chain, I always put the new chain on my best bike and the chain from it on the bike that had the worn chain. That way my best bike always has a practically new chain on it which will hopefully make the more expensive cassette and chainrings on it last longer.


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