How to tell when chainrings are due for changing?
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Jase



Joined: 24 Jan 2011
Posts: 503
Location: Saltaire, W. Yorks

PostPosted: Wed Aug 10, 2016 5:50 pm    Post subject: How to tell when chainrings are due for changing? Reply with quote

I've got a standard crank on one of my bikes which looked to have worn rings pre-cleaning (SRAM force for reference) but when I had a good look at them yesterday evening and cleaned off some horrible sticky gunky oil off them I'm now unsure if they need replacing or not.

How do you actually tell?

I've put the rings up against some that I know are newish and have very little wear and they didnt look hugely different to me. The old rings are black alloy and the anodising has worn in places as is to be expected but the teeth don't look to be curved as such which seemed to be an indicator when I did some Internet searching. Also it does still have teeth - I've seen pics of rings that had almost been worn round!!

I'm changing chain and cassette and will consider the rings too as I don't want to cause stress on a new chain with overly worn rings. But I'm totally unsure if it needs it! Any pointers and tips gratefully received.

Cheers
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Richard A Thackeray



Joined: 31 Jan 2009
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Location: Normanton, Wakefield. West Riding Of Yorkshire

PostPosted: Wed Aug 10, 2016 8:46 pm    Post subject: Reply with quote

Chain-suck is one pointer

Smaller rings tend to exhibit wear patterns first (less teeth to take the load?)

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Jase



Joined: 24 Jan 2011
Posts: 503
Location: Saltaire, W. Yorks

PostPosted: Wed Aug 10, 2016 9:12 pm    Post subject: Reply with quote

Cheers Richard. There did seem to be a bit of chain suck, but the sticky gunky on the chain set wasnt helping nor the terribly stretched chain. Guess it's a case of giving it a go with the new chain and cassette plus re-lubing and see what happens?

The teeth don't look to resemble shark fins, but they also don't quite look as good as the newer rings.

I can try stick some pics up?
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Magnus



Joined: 18 Jan 2013
Posts: 1512
Location: Leicester

PostPosted: Thu Aug 11, 2016 9:13 am    Post subject: Reply with quote

I don't know what the pro mechanics do but what i do is,
1 look for excessive curving of the teeth,
2 when i fit my new chain i put load on on the pedals then look to see where the chain is sitting on the ring. If it is riding up the teeth and you can see daylight between the chain and the chain-ring where the chain normally sits in between the teeth then it is time to sling it/them and fit new.

as a commuter i tend to get through a chain set every 2 years approx 12000 miles. using Shimano XT chain set and chain, riding on gritty canal towpaths. I would expect it to last longer on the road. Bare in mind i am talking about a mountain bike. My roadie is Campagnola Chorus equipped and i have never had to change a chain ring, not in 10 years plus Cool Cool

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Jase



Joined: 24 Jan 2011
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Location: Saltaire, W. Yorks

PostPosted: Thu Aug 11, 2016 9:17 pm    Post subject: Reply with quote

New chain arrived in the post today and I've had a look at how it goes with the worn chainrings. The chain does move slightly on the teeth and the teeth are clearly a bit worn but it's not lifting off the teeth so that you can see daylight so might well be OK for a few miles yet.

It was lifting horribly with the worn chain - have made note to self to use chain tool to check wear more regularly.
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Richard A Thackeray



Joined: 31 Jan 2009
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Location: Normanton, Wakefield. West Riding Of Yorkshire

PostPosted: Fri Aug 12, 2016 5:09 pm    Post subject: Reply with quote

Magnus wrote:
My roadie is Campagnola Chorus equipped and i have never had to change a chain ring, not in 10 years plus Cool Cool


My old (1994)Dyna-Tech has a Chorus chainset, & that was used as a year-round commuter, circa 2009 - 2013

It still has the original rings, after all that time!, numerous new chains over the years though

All other componentry on it, barring the bottom-bracket (a Chorus) is Ultegra 8-speed

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dave0w



Joined: 25 Jun 2013
Posts: 231

PostPosted: Tue Aug 16, 2016 3:58 pm    Post subject: Reply with quote

you look at them.. when your teeth look like shark fins there worn and need to be replaced


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Steve Kish



Joined: 06 Jan 2009
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Location: Near Heathrow

PostPosted: Thu Aug 18, 2016 12:40 am    Post subject: Reply with quote

Unlike a cassette sprocket that has far less teeth engaged and thus less wraparound, you can get by with far more wear on chainrings.

Slightly strange as sprockets are hardened steel and chainrings usually alu alloy.

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Jase



Joined: 24 Jan 2011
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Location: Saltaire, W. Yorks

PostPosted: Thu Aug 18, 2016 9:09 am    Post subject: Reply with quote

The teeth aren't curved and with the new chain (and also a new cassette) the bike seems to be riding nicely.

I guess being mindful of the wear is no bad thing.

It prompted me to do some checking on my winter steed which revealed that the chain needs replacing. It's not done too bad having been commuted on through winter, probably done just shy of 2,000 miles in total but with the battering it'll have had through winter I'm ok with that. Changing it now before the cassette takes a battering.
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