Bent Teeth on Chainring

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CycloVelo
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Bent Teeth on Chainring

Postby CycloVelo » Tue Nov 20, 2018 8:23 am

Hello,

Just had an issue where the chain kept coming off during a ride yesterday on my gravel bike. I'm running a Rotor 1x chainring on the front.

After about the 5th time this happened, I finally decided to properly stop and have a look and discovered 3 obviously bent teeth on the ring that derailed the chain every time it came around. It then occurred to me that I did go through a particularly rough trail over the weekend and remembered on one occasion a crunch and clunk as I pedaled over the rough terrain.

So, my question is whether the chainring is cactus, or if I can continue to ride with it now that I've bent the offending teeth back into place?? I'm pretty sure the chainring is aluminium.

Mike Ayling
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Re: Bent Teeth on Chainring

Postby Mike Ayling » Tue Nov 20, 2018 8:41 am

I would continue riding and see what happens!

Mike

Tamiya
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Re: Bent Teeth on Chainring

Postby Tamiya » Tue Nov 20, 2018 8:43 am

If you've solved the chain-falling-off, it's fine.

Have seen single rings missing 1/2/possibly3 teeth and they still work... :)

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ColinOldnCranky
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Re: Bent Teeth on Chainring

Postby ColinOldnCranky » Tue Nov 20, 2018 1:35 pm

If the chainring IS aluminium then it's got almost no life in it from the moment you first turned it so it's no loss to ditch it.

Just kidding. But the chairing would HAVE to be something harder wearing than aluminium.
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Mububban
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Re: Bent Teeth on Chainring

Postby Mububban » Tue Nov 20, 2018 3:03 pm

Keep riding. I bent my old chainring, bashed it straight again when i got home, and it kept going perfectly :)
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piledhigher
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Re: Bent Teeth on Chainring

Postby piledhigher » Tue Nov 20, 2018 3:40 pm

ColinOldnCranky wrote:Just kidding. But the chairing would HAVE to be something harder wearing than aluminium.


Chain rings on all but the crappiest bikes are aluminium.

I'll forgive your lack of knowledge due to the lack of a chainring on your conveyance!

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TrikeTragic
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Re: Bent Teeth on Chainring

Postby TrikeTragic » Tue Nov 20, 2018 3:41 pm

Read the title of the thread, thought to self "someone really needs some iron in their diet if their munching on a chain ring..." :roll:

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bychosis
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Re: Bent Teeth on Chainring

Postby bychosis » Tue Nov 20, 2018 3:46 pm

Bashing it back into shape is always the best first option. If it works keep riding until something else goes wrong. If it doesn’t work you’ve lost nothing by trying to straighten it.
bychosis (bahy-koh-sis): A mental disorder of delusions indicating impaired contact with a reality of no bicycles.

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Duck!
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Re: Bent Teeth on Chainring

Postby Duck! » Tue Nov 20, 2018 3:53 pm

It has a finite life anyway; just run it until it dies.
I had a thought, but it got run over as it crossed my mind.

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Duck!
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Re: Bent Teeth on Chainring

Postby Duck! » Tue Nov 20, 2018 3:55 pm

TrikeTragic wrote:Read the title of the thread, thought to self "someone really needs some iron in their diet if their munching on a chain ring..." :roll:

Cheers

Won't get much iron from an aluminium ring. ;)
I had a thought, but it got run over as it crossed my mind.

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Duck!
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Re: Bent Teeth on Chainring

Postby Duck! » Tue Nov 20, 2018 10:56 pm

ColinOldnCranky wrote:If the chainring IS aluminium then it's got almost no life in it from the moment you first turned it so it's no loss to ditch it.

Just kidding. But the chairing would HAVE to be something harder wearing than aluminium.

Most chainrings these days are aluminium, usually 7050 or 7075 alloys which are quite hard-wearing as far as aluminium goes. Exact wear rate is dictated by several factors, but at the end of the day, all chainrings, regardless of material, have a finite life.
I had a thought, but it got run over as it crossed my mind.

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CycloVelo
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Re: Bent Teeth on Chainring

Postby CycloVelo » Wed Nov 21, 2018 7:46 am

Thanks all. On closer inspection, it would appear that the chainring is worn and that may have caused the slipping of the chain, leading to the bent teeth. But I'm a little shocked to see many of the teeth already "shark-toothed" as it has only been maybe 3,000km since I put it on and I regularly clean and maintain the drivetrain. Chain is of the same vintage and shows 0.5 on the Park Tool chain checker. :?

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ColinOldnCranky
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Re: Bent Teeth on Chainring

Postby ColinOldnCranky » Wed Nov 21, 2018 11:18 am

Sorry to confuse peeps. While I would never refer to steel as iron, likewise I always differentiate between aluminum (soft like lead) and aluminium alloy (whatever properties one wants) and would not use the terms interchangeably.

I should have differentiated between aluminium and aluminium alloy. My bad. :oops:

Which reminds me, I should check on the iron bearing on the unicycle to make sure they are still good. :mrgreen:
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AUbicycles
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Re: Bent Teeth on Chainring

Postby AUbicycles » Wed Dec 05, 2018 9:15 am

CycloVelo wrote:But I'm a little shocked to see many of the teeth already "shark-toothed" as it has only been maybe 3,000km since I put it on and I regularly clean and maintain the drivetrain.


3,000 k isn't much and I get so much more out of that... although gravel and MTB through up a lot more dirt and sand which increase wear (not so mention other stresses compared to road cycling).

I am sure Duck! will have good input but I would want to know if you put on a new chain with the chain ring. Did you measure the chain for stretch. Are you doing a lot of wet weather gravel riding (which I would argue would increase wear over dry riding with suitable lube).

My commuter bike with 'simple' gear is probably at about 8K and I rarely clean and maintain even though it goes through rain and picks up plenty of grit and is still on the original chain, cassette and chainrings. Less torque than on the other bikes though.

uart
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Re: Bent Teeth on Chainring

Postby uart » Wed Dec 05, 2018 6:47 pm

AUbicycles wrote:3,000 k isn't much and I get so much more out of that...


Yeah I agree. I get more than that out of just a chain. I've got a couple of old bikes here that have done at least 20,000 km with the original alloy chain rings.

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CycloVelo
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Re: Bent Teeth on Chainring

Postby CycloVelo » Thu Dec 06, 2018 8:36 am

I must confess I'm a bit mystified myself as I was expecting much more mileage out of the chainring. I use Squirt lube and maintain the drivetrain using their instructions, which is to not degrease the chain but just to wipe it down/brush it and then apply some more lube. Not sure if that may be contributing to the problem, but drivetrain appears to run pretty quietly using that method.

Have now put on a new SRAM chainring with new chain, we'll see how that goes.

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