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How to tell if chainrings are too worn?

Old 08-21-22, 11:33 AM
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rbrides
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How to tell if chainrings are too worn?

Are these chainrings too worn?

How do you test, judge or decide if your chainrings need to be replaced?



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Old 08-21-22, 02:14 PM
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'02 nrs
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wrap a new chain around the ring & compare how much movement the chain moves when holding the ends tight.compare to a new chainring.
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Old 08-21-22, 03:59 PM
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https://www.sheldonbrown.com/chain-wear.html
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Old 08-21-22, 04:01 PM
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Originally Posted by '02 nrs
wrap a new chain around the ring & compare how much movement the chain moves when holding the ends tight.compare to a new chainring.
With a new chain on the bike, apply pressure with the crank. If you see daylight between the fronts of the teeth and the backs of the chain links at the top of the ring, it's time for a new one.
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Old 08-22-22, 06:25 AM
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Originally Posted by '02 nrs
wrap a new chain around the ring & compare how much movement the chain moves when holding the ends tight.compare to a new chainring.
That is a great method. I suppose it would be a judgement call as to how much movement is too much.
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Old 08-22-22, 06:29 AM
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Originally Posted by oldbobcat
With a new chain on the bike, apply pressure with the crank. If you see daylight between the fronts of the teeth and the backs of the chain links at the top of the ring, it's time for a new one.
another great tip. Excellent.
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Old 08-22-22, 06:40 AM
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The few times I've been able to wear one out I noticed excessive drive train noise that didn't go away with oiling.

From the photo, I'd suspect the small chainring. It looks like the teeth are starting to get the "shark fin" shape, and there may be a burr on the leading edge.
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Old 08-22-22, 09:26 AM
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Originally Posted by andrewclaus
From the photo, I'd suspect the small chainring. It looks like the teeth are starting to get the "shark fin" shape, and there may be a burr on the leading edge.
Agree that the small ring is worn or "starting to go." It looks like the OP is spending all their time on the small ring. This is why, when possible, it is better to use the big ring and therefore the bigger cogs on the cassette. More chain ring and cog teeth engaged means much longer life for both the chain rings and cassette.
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Old 08-22-22, 09:35 AM
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Originally Posted by KerryIrons
Agree that the small ring is worn or "starting to go." It looks like the OP is spending all their time on the small ring. This is why, when possible, it is better to use the big ring and therefore the bigger cogs on the cassette. More chain ring and cog teeth engaged means much longer life for both the chain rings and cassette.
...and perhaps add that prompt chain replacements will increase life of all drivetrain pieces.
The silver lining with his worn small ring is that it costs far less than the big ring. lol
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Old 08-26-22, 08:36 AM
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Originally Posted by roadcrankr
...and perhaps add that prompt chain replacements will increase life of all drivetrain pieces.
The silver lining with his worn small ring is that it costs far less than the big ring. lol
I habitually clean my chain with Park Tools Chain scrubber using Simply Green concentrate and replace the chain when it gets to .75, as measured by Park Tools CC 3.2. In fact, the inpetus for my post is my concern about how frequently I am replacing the chain. I'm only getting 500-700 miles of mostly gravel roads until it hits .75. Since I clean it so frequently I've begun to suspect the chainrings are wearing out the chain.

Could the acelerated chain wear be caused by the chain rings?
Could the acelerated chain wear be caused by the Simple Green cleaning solution?

I think the answer to both of those questions is "no", but I'm open minded to learning otherwise.
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Old 08-26-22, 08:38 AM
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Originally Posted by andrewclaus
The few times I've been able to wear one out I noticed excessive drive train noise that didn't go away with oiling.

From the photo, I'd suspect the small chainring. It looks like the teeth are starting to get the "shark fin" shape, and there may be a burr on the leading edge.
thanks
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Old 08-26-22, 08:40 AM
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Originally Posted by roadcrankr
...and perhaps add that prompt chain replacements will increase life of all drivetrain pieces.
The silver lining with his worn small ring is that it costs far less than the big ring. lol
thanks
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Old 08-26-22, 09:29 AM
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Originally Posted by rbrides
I habitually clean my chain with Park Tools Chain scrubber using Simply Green concentrate and replace the chain when it gets to .75, as measured by Park Tools CC 3.2. In fact, the inpetus for my post is my concern about how frequently I am replacing the chain. I'm only getting 500-700 miles of mostly gravel roads until it hits .75. Since I clean it so frequently I've begun to suspect the chainrings are wearing out the chain.

Could the acelerated chain wear be caused by the chain rings?
Could the acelerated chain wear be caused by the Simple Green cleaning solution?

I think the answer to both of those questions is "no", but I'm open minded to learning otherwise.
Worn chain rings can indeed accelerate chain wear. So can using a chain checker accelerate perceived chain wear. Just use a ruler. A ruler is much more accurate than most chain checkers. Even with worn rings I would be extremely surprised if you were wearing out chains at 500 miles.
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Old 08-27-22, 04:36 PM
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cleaning can hasten wear

Originally Posted by rbrides
I habitually clean my chain with Park Tools Chain scrubber using Simply Green concentrate and replace the chain when it gets to .75, as measured by Park Tools CC 3.2. In fact, the inpetus for my post is my concern about how frequently I am replacing the chain. I'm only getting 500-700 miles of mostly gravel roads until it hits .75. Since I clean it so frequently I've begun to suspect the chainrings are wearing out the chain.

Could the acelerated chain wear be caused by the chain rings?
Could the acelerated chain wear be caused by the Simple Green cleaning solution?

I think the answer to both of those questions is "no", but I'm open minded to learning otherwise.
For a time I obsessively cleaned my chains weekly by removing a first chain and placing it in an old soda bottle with simple green while mounting a second chain. After shaking up the bottle, the first chain was hung up to dry. Both chains wore out it half the mileage that I normally got from chains that I didn't clean. My theory is my cleaning facilitated grit getting into the links and wore them out faster.
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Old 08-27-22, 05:10 PM
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Is it giving you issues with the chain skipping over it when you put some power into the pedals to accelerate hard?

I don't see a lot of wear. Why don't you compare it to a pic of a brand new set from the manufacturer's website. You need to do that tooth for tooth after finding the same tooth. Different teeth can have different shapes. Some quite pointier than you'd think.

Seems like a good way to tell if it is worn is after you put on a new chain and it skips on the ring or rings. Similarly it's the same way I decide if the cogs on the rear are worn.
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Old 08-28-22, 07:50 PM
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It looks like a couple of the valleys are elongated a bit, so there is some wear. The greatest wear is usually at 90 degrees off from where the crank arms are.

But, I typically just go by actual symptoms.

Dropping the chain when not expecting it?
Noise?
Something else?

If it was me, I'd put the rings back on. If you can ride it just fine, keep riding. I suppose it might be a bit different if you're racing, but still, no need to preemptively replace when asymptomatic.
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Old 08-29-22, 09:21 AM
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Originally Posted by kommisar
For a time I obsessively cleaned my chains weekly by removing a first chain and placing it in an old soda bottle with simple green while mounting a second chain. After shaking up the bottle, the first chain was hung up to dry. Both chains wore out it half the mileage that I normally got from chains that I didn't clean. My theory is my cleaning facilitated grit getting into the links and wore them out faster.
That is quite curious. Thanks for posting. Your theory isn't that the chemicals in Simply Green were contributory, just that the act of cleaning pushed grit in the links.
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Old 08-29-22, 09:22 AM
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Originally Posted by Iride01
Is it giving you issues with the chain skipping over it when you put some power into the pedals to accelerate hard?

I don't see a lot of wear. Why don't you compare it to a pic of a brand new set from the manufacturer's website. You need to do that tooth for tooth after finding the same tooth. Different teeth can have different shapes. Some quite pointier than you'd think.

Seems like a good way to tell if it is worn is after you put on a new chain and it skips on the ring or rings. Similarly it's the same way I decide if the cogs on the rear are worn.
Good hands-on approach. Thank you.
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Old 08-29-22, 09:25 AM
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Originally Posted by CliffordK
It looks like a couple of the valleys are elongated a bit, so there is some wear. The greatest wear is usually at 90 degrees off from where the crank arms are.

But, I typically just go by actual symptoms.

Dropping the chain when not expecting it?
Noise?
Something else?

If it was me, I'd put the rings back on. If you can ride it just fine, keep riding. I suppose it might be a bit different if you're racing, but still, no need to preemptively replace when asymptomatic.
Thank you. My only symptom is the rapid rate the chains are wearing out, as guaged by the Park Tools chain checker. Others' replys elaborate on the use of chain checkers' accuracy and the like.
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Old 08-29-22, 10:22 AM
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Originally Posted by rbrides
That is quite curious. Thanks for posting. Your theory isn't that the chemicals in Simply Green were contributory, just that the act of cleaning pushed grit in the links.
Yes. I believe that disolving grit allowed it to get into the link and substantially increased the rate of wear.
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Old 08-29-22, 10:29 AM
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Originally Posted by KerryIrons
Worn chain rings can indeed accelerate chain wear. So can using a chain checker accelerate perceived chain wear. Just use a ruler. A ruler is much more accurate than most chain checkers. Even with worn rings I would be extremely surprised if you were wearing out chains at 500 miles.
My first thought also. I replace when 12" of chain "stretches" to 12-1/16", measured front of pin to front of pin. (Don't bother trying to estimate the centers.) Many chains show roller wear (or there may just be some "seating in") almost right away. But the ruler approach doesn't see the roller wear at all; just what matters.

Many chain checkers add the "stretch" (quotation marks because it is wear, not stretch but every body knows what you are talking about) to roller wear. Roller wear doesn't matter. They all wear the same and after the wear, the entire chain shifts that distance relative to the chainring or cog teeth. (I suppose you could argue "I should have won that race but my cassette was lagging because of roller wear" but I doubt you will convince the jury.)
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Old 08-29-22, 11:17 AM
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Two thoughts on Simple Green. 1) the factory grease is deep inside the rollers and hardest places to get lubrication to. We have no means to get anything like it that deep. Simple Green strips it out. And 2) long soaks of Simple Green with certain high strength steel has been known to compromise its strength and lead to failures in use. Chains soaked in SG have broken while riding. Not a metallurgist so I do not know the mechanism and Simple Green wasn't around when I took Materials and Metallurgy a long time ago.

I do know that high strength steels can be compromised and fail when least expected; perhaps years and thousands of miles later. I rode a compromised Columbus SL fork down 2000' on my fix gear 3 years and 8000 miles after the freshly built fork was nickle plated but not heat treated. Plater knew it had to get the $60 heat treat but didn't say anything. I arrived home on a bike that shuddered wildly every time I touch the front brake. Tried spreading the fork with my hands. I'm barely strong enough to permanently spread a not so strong fork of ordinary steel. The right blade immediately bent at at the crown 30 degrees. There was a crack 2/3s the way around. Another on the other blade of 1/3.

The little "moral" of this story - that bike won my heart over that day. A "mountain" fix gear, designed to be able to re-cog to any available fix gear cog without messing with chain length. I was doing that ride to prepare for its second Cycle Oregon in very hilly country. Got to the ride high point, screwed on the tiny cog for all the descending and could not get the chain to behave. It kept going tight, then loose. Finally set it too loose and just babied the bike down using plenty of both brakes, never going fast at all and just cruising through the fun, fast turns. One of those turns I loved to come into fast and brake hard at the last second and fly around on its banking. Would have folded that fork instantly.

That mechanical was really dumb. I run a Miche track hub. Threading for the lockring is Italian standard, not English/ISO. Bigger diameter. On ISO track hubs, a special bell-shaped lockring is needed to use a 12 tooth cog or the chain will sit on the lockring (and occasionally fall into the spanner holes). Well, on a Miche hub, the 13 tooth needs that same bell lockring. That was why my chain misbehaved. The bike (Jessica J from conception) waited until I was going to have this learning experience to have the failure we doomed it with when the fork was built, plated and not heat treated. And like I said above, won a big piece of my heart.

Back to chains - I no longer take them off and clean them. I wipe them clean running them trough a rag. (Left pinkie around the seatstay, fingers and rag arond the chain and I pedal the bike with my right. Sometimes take a q-tip and clean between the rollers but not usually. Wipe ring and cog teeth clean with a rad. Cassettes with a sock. Nothing fancy. Drip TriFlo or the wet MTB Finish Line onto each roller/inner/outer plate, spin the cranks a few times, do another wipe and call it good.
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Old 08-29-22, 12:42 PM
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I'm a poor expert on this subject so do prioritize other responses over mine. That said, I've struggled mightily with this same issue and feel that I've learned a few things of value the hard way. Here's what I think I know:

1) With the ramping and pinioning, it can be very easy to mistake deliberately profiled teeth for teeth that are broken or damaged somehow.

2) I gather that you only need the ramping etc for shifting from smaller rings to larger rings. It's not an issue on the drop down I guess. This means that you can't always expect two adjacent rings to have highly similar tooth profiles. One one of my new doubles, the small ring looks quite different from the large ring. Much more uniform with respect to adjacent tooth profiles.

3) As I understand the shark tooth thing:

a) Wave patterns cresting towards the back wheel usually indicate excessive chain wear.

b) Wave patterns cresting towards the front wheel usually indicated true chainring wear.

Lately, when I replace my chainrings, I take high resolution photos of them from above before installing them. My hope is that I'll be able to overlay those photos with future "as-is" chainring wear photos to make any differences apparent. But, yeah, testing performance on a new chain seems to be the simplest approach.
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