Bent Teeth on Chainring

[CycloVelo]

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]

I would continue riding and see what happens!

Mike

[Tamiya]

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

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

[ColinOldnCranky]

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.

[Mububban]

Keep riding. I bent my old chainring, bashed it straight again when i got home, and it kept going perfectly

[piledhigher]

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!

[TrikeTragic]

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

Cheers

[bychosis]

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.

[Duck!]

It has a finite life anyway; just run it until it dies.

[Duck!]

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

Cheers

Won't get much iron from an aluminium ring.

[Duck!]

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.

[CycloVelo]

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.

[ColinOldnCranky]

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.

Which reminds me, I should check on the iron bearing on the unicycle to make sure they are still good.

[AUbicycles]

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]

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.

[CycloVelo]

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.

[wqlava1]

There is a tool available from Unior (good quality tools they make too) for truing chainrings. It's got a block of metal on the end of a handle with two slots - the thinner for bending individual teeth and the thicker for when the spider's bent. With the dimensions they give you could make your own pretty effectively out of some hardwood like redgum or something equivalently dense.
http://www.unior-bike.com/?doc=10780&prod=88304
https://www.bike24.com/p2159222.html

Late one night about 3 years back I hit a wombat that was scared of my light and running across the path, with my single Surly stainless chainring. It was bent by over a cm for about 6 or 8 teeth and the chain was coming off. Luckily a group of MTB riders came past soon after and one had a pair of pliers. Another member of their group (Huw from Commuter Cycles) bent it back with a couple of well chosen twists. I couldn't work out where the problem had been when I checked it later with a dial guage!

I have actually got the Unior tool but have needed to use it only once - if I was more skillful maybe pliers or multigrips would be fine.

[jackthelad]

Did you use the chain checker for 5 to 10 speed or for 10 to 12 speed chain
, the new longer park tool chain checker is different