Worn Chainring?

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hugh stone
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Worn Chainring?

Postby hugh stone » Wed Feb 26, 2014 12:31 am

I think the my large chainring (50T) might be on its way out but given all the tooth profiling that goes on I'd really appreciate a second opinion.ImageImage

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Duck!
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Re: Worn Chainring?

Postby Duck! » Wed Feb 26, 2014 1:47 am

I reckon that's still got some life in it. What sort of distance do you reckon it's done?
I had a thought, but it got run over as it crossed my mind.

MN GLXR
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Re: Worn Chainring?

Postby MN GLXR » Wed Feb 26, 2014 6:37 am

With a chain on the ring, how far can you lift the links off the ring? Is it snug or loose?

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Marx
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Re: Worn Chainring?

Postby Marx » Wed Feb 26, 2014 7:25 am

Can you lift a chain link at 3 o'clock on the chainwheel & get more than half a tooth's height of daylight underneath?

If you can, then you still have plenty of kms left in it... :wink:
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KGB
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Re: Worn Chainring?

Postby KGB » Wed Feb 26, 2014 8:29 am

Lifting the chain is more an indication of chain wear ("stretch") than ring wear.

Still some life there IMO
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hugh stone
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Re: Worn Chainring?

Postby hugh stone » Wed Feb 26, 2014 9:08 am

Only about 7,000kms on the chainring - 95% of which would be on the big ring. About half way through my third chain in that time. I realise this is not a lot of 'mileage' for chainrings but it cops a bit from the commute, rain and overall drivetrain neglect.
It hasn't been slipping but the fin like shapes which are emerging concerned me.

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jules21
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Re: Worn Chainring?

Postby jules21 » Wed Feb 26, 2014 10:39 am

my experience is that the chainring needs replacing when the chain starts slipping. this usually happens when i fit a new chain - which won't engage with a sufficiently worn 'ring.

running a chainring to 'failure' probably wears chains faster, but chains are cheaper than 'rings so i think it makes sense.

i always keep a set of spare 'rings so that i don't have to park the bike while waiting for replacements to arrive.

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RonK
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Re: Worn Chainring?

Postby RonK » Wed Feb 26, 2014 1:03 pm

Looks ok to me...
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hugh stone
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Worn Chainring?

Postby hugh stone » Wed Feb 26, 2014 5:21 pm

Thanks RonK - looks like the teeth are already a bit fin like to start with. Think I'll just keep them on until they start slipping 'cos damned if in can tell what a worn one looks like.

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RonK
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Re: Worn Chainring?

Postby RonK » Wed Feb 26, 2014 6:21 pm

Yeah, unless you are very familiar with them it's difficult to gauge the wear visually.

I don't think you need a replacement, but they aren't too expensive to have a spare handy which can be used as a reference.

Maybe order one with your next chain.
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Marx
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Re: Worn Chainring?

Postby Marx » Wed Feb 26, 2014 7:33 pm

off topic, but I personally don't understand how new chains on worn chainrings/cogs helps things?
I just ride the whole groupset into the ground & replace everything in one go, the indicator being a jumping chain on my most popular cassette cog.
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Nobody
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Re: Worn Chainring?

Postby Nobody » Wed Feb 26, 2014 8:10 pm

Marx wrote:off topic, but I personally don't understand how new chains on worn chainrings/cogs helps things?
It saves money by allowing you to get the maximum life you can from each component. I usually change the chain when the length measurement indicates it should be, then see how everything else sounds or feels. Last time I knew the big chainring was finished because after I changed the chain and cassette, I could hear the chain make an odd rattling/chattering sound. It was so loud peds could hear me coming. Once I changed the chainring, the chattering stopped.

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KGB
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Re: Worn Chainring?

Postby KGB » Wed Feb 26, 2014 8:10 pm

New chains on very worn cogs won't work, it will skip. Even if it doesn't work, the worn cogs will accelerate the wear on the new chain.

What most people advocate is rotating between 3 chains every 1000km or so. Since the chain is what wears out the cogs, a worn and "stretched" chain will increase this rate of wear. By keeping new-ish, good condition chains on the bike you minimise the rate of wear on the cogs and that's the whole point.
New cassette on my bike = $200. New chain, about $40 at most.

Riding the whole lot into the ground is fine if that works for you. On a high end 10 or 11 speed road bike most people won't tolerate the degradation in shifting you get as you begin to run it into the ground. It will still "work" but not as well as it should.
On my 7 speed mtb, the shifting is more robust, largely due to the fact that there is so much more travel between cogs. This decreased sensitivity to wear and adjustment, plus the fact I don't race my mtb means I'm pretty much following the run it into the ground method for that bike.
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Duck!
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Re: Worn Chainring?

Postby Duck! » Thu Feb 27, 2014 2:07 pm

Chainrings are longer-lived due to the large contact area. Unless you persist with a badly-worn chain, which will sit on the tips of the teeth rather than mesh properly, then it will rapidly wear the teeth off. If your chains are replaced before they're allowed to go too far, rings will last a very long time.
I had a thought, but it got run over as it crossed my mind.

dontazame
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Re: Worn Chainring?

Postby dontazame » Tue Mar 04, 2014 8:24 am

Does anyone else rotate their small chain ring? I find it wears way quicker than the large, and there is a definite wear pattern.

Hugh Stone old
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Re: Worn Chainring?

Postby Hugh Stone old » Tue Mar 04, 2014 8:33 am

I rotate it every time I ride :-)

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scotto
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Re: Worn Chainring?

Postby scotto » Tue Apr 01, 2014 11:33 pm

Rotate the chainring ??!!! It's April 1 today At least !!

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ColinOldnCranky
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Re: Worn Chainring?

Postby ColinOldnCranky » Wed Apr 02, 2014 12:22 am

KGB wrote:Lifting the chain is more an indication of chain wear ("stretch") than ring wear.

Still some life there IMO

I haven't thought it through but I would have thought that that was more a case of how much stretch there is in the chain.
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kb
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Re: Worn Chainring?

Postby kb » Wed Apr 02, 2014 3:34 pm

Not if you use a new chain though.
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