how worn are my chainrings?

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22camels
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how worn are my chainrings?

Postby 22camels » 20 Apr 2015, 1:33pm

I have been trying to get a better understanding of chainring wear - but to be honest i'm still not too sure how to tell when a ring needs replacing.

So below is a Shimano Tiagra FC-4503 crankset after approx 7000km of use in 4 years. How much life (in km or miles) is left in these rings?

crank-6621-2.JPG


It must be pretty clear I've used the big ring much less than the other two :).

Ugly
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Re: how worn are my chainrings?

Postby Ugly » 20 Apr 2015, 2:49pm

My view on chainring wear is: don't worry too much what it looks like, what does it feel like, does the transmission feel smooth and is the front changer changing well. if the answer is yes then don't change it.

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Vantage
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Re: how worn are my chainrings?

Postby Vantage » 20 Apr 2015, 3:12pm

I asked a similar question here recently. You're good for 50,000 miles and maybe more. If the chain shifts ok and doesn't jump or slip, it's basically ok.
Bill


“Ride as much or as little, or as long or as short as you feel. But ride.” ~ Eddy Merckx
It's a rich man whos children run to him when his pockets are empty.

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Paulatic
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Re: how worn are my chainrings?

Postby Paulatic » 20 Apr 2015, 5:08pm

Image
Just going to renew this one, it's giving me constant chainsuck with a new chain.
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CREPELLO
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Re: how worn are my chainrings?

Postby CREPELLO » 20 Apr 2015, 8:24pm

Paulatic wrote:Just going to renew this one, it's giving me constant chainsuck with a new chain.
It should be quite possible to turn that chain ring around, giving as good as new. This trick usually only works with granny rings, which are more or less symmetrical.

Even if you couldn't reverse it, it's clear what's causing the chain suck. Removing those burrs with a needle file should fix it. I think the teeth have to be properly hooked before the situation becomes terminal.

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Paulatic
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Re: how worn are my chainrings?

Postby Paulatic » 20 Apr 2015, 8:49pm

Did wonder about those burrs. . A job for the Drevel in the morning I think.
Thanks for the info.
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Brucey
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Re: how worn are my chainrings?

Postby Brucey » 20 Apr 2015, 10:16pm

Paulatic wrote:Just going to renew this one, it's giving me constant chainsuck with a new chain.


FWIW I agree with Crepello, between dressing and turning that chainring is far from dead yet....

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Vantage
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Re: how worn are my chainrings?

Postby Vantage » 21 Apr 2015, 8:44am

My granny ring looked like that not long after I'd bought the bike. From what I'd read somewhere (here I think) it was a common problem as the chain bedded in the ring. I dremelled the burrs off and instantly had chainsuckless gear changes.
Bill


“Ride as much or as little, or as long or as short as you feel. But ride.” ~ Eddy Merckx
It's a rich man whos children run to him when his pockets are empty.

22camels
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Re: how worn are my chainrings?

Postby 22camels » 21 Apr 2015, 10:35pm

thanks, yeah it feels smooth and shifts ok, it's just I have one eye on long distance touring and wondering how much advance notice i'd get if a ring needed replacing. 50,000 miles sounds a tad optimistic.

andy65
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Re: how worn are my chainrings?

Postby andy65 » 21 Apr 2015, 10:46pm

The test usually comes when you change the chain and you start getting 'chain suck'. This is when the new chain without warn links binds to the teeth of the chainring because of the worn teeth.