Does this crankset look worn out?

[Jimmy Doug]

Hi

Whilst cycling 3000 kms in dreadful Norwegian weather this year, my transmission seemed very rough. As soon as I got back, I changed the chain - but it still seemed rough and only lasted about 1000 kms. I thought that was very premature, so I changed the chain again and also changed the cassette. But after only 500 kms my chain is already very worn out (I can fit both ends of the chain checker in the chain, and I can also lift the chain off the chainring whilst in the big/big combination to expose the chainring teeth).
I'd like someone's opinion about the chainset. It seems to me fine (it has only done 13 000 kms), but after having gone through two chains really quickly and changed the cassette, the only other thing I can think of is that the chainset is worn. What do you think? Here are two pics ( I use the middle chain ring the most):

 

[smokeysmoo]

Just employing the shark tooth theory it looks OK too me TBH*



*I am no expert though

 

[MattHB]

Looks ok to me

 

[Jimmy Doug]

I thought it was OK too - only small shark's teeth. However, I've just gone round looking at all the teeth in the middle ring closely. There appears to be tiny shards of metal. I can imagine them very quickly chewing into the chain. Here is a close up:

 

[ianrauk]

Plenty of life left in that imo

 

[gbb]

Looking at photo no 2 on the first post, the middle ring at 9 oclock and below looks quite worn, quite shark toothed. At 13K km, i'd say you'd done ok, Is it an expensive chainset ?, the price of two chains is making a cheap one..quite expensive. If its a cheapish one, i'd replace regardless at that mileage.
You mention big/big combination ...do you ride that combo ?, bad thing if you do, you'll accelerate wear anyway doing that.

 

[smokeysmoo]

There appears to be tiny shards of metal

I'd probably file them down if money's tight but then fit a decent chain.

Not saying you've been fitting crap ones by any means, but I stick to KMC chains these days and I'm very happy with their performance

On the other hand, and if money's no object, for the mileage it's done I'd maybe just whack new rings on it and replace the chain, job done.

 

[02GF74]

rings look worn, but unevenly.

take the outer one - look at how narrow the tips are at 8 o'clock position compared to the ones at 5 o'clock position.

worn rings have to be extremely bad for the chain to jump but they will wear a chain and subsequently the cassette after very low miles.

check out the price of a new chainset as the cost of replacement rings can be almost the same.

 

[Jimmy Doug]

Thanks for the input, guys.

Looking at photo no 2 on the first post, the middle ring at 9 oclock and below looks quite worn, quite shark toothed. At 13K km, i'd say you'd done ok, Is it an expensive chainset ?, the price of two chains is making a cheap one..quite expensive. If its a cheapish one, i'd replace regardless at that mileage.
You mention big/big combination ...do you ride that combo ?, bad thing if you do, you'll accelerate wear anyway doing that.

This is a very cheap chainset - standard fit on a 2010 Revolution Country Traveller. Thinking of replacing it for a Shimano Alivio.
I do not ride the big/big combination - I just put the chain in that position because there's a second way of checking chain wear based on being able to pull the chain off the chainring in this combo. If you can't pull off the chain off the teeth, it should be good. I could do this.

 

[Jimmy Doug]

rings look worn, but unevenly.

take the outer one - look at how narrow the tips are at 8 o'clock position compared to the ones at 5 o'clock position.

Any ideas about what could cause this?

 

[amaferanga]

How does a worn chainring eat into a chain? I can't see how that'd happen. A worn chain will wear out a new chainring, but not the other way round as far as I can tell.

Hard to tell from the pictures how bad it is, but remember that not all teeth will look the same when new anyway.

 

[RecordAceFromNew]

How does a worn chainring eat into a chain? I can't see how that'd happen. A worn chain will wear out a new chainring, but not the other way round as far as I can tell.

Hard to tell from the pictures how bad it is, but remember that not all teeth will look the same when new anyway.

+1.

See the 8 o'clock and 5 o'clock ones of a brand new Deore 48T below (suspect OP's large is 48T). Also the seemingly broken/shortened ones at 6 and 12 o'clock. They are of course entirely normal and are shaped (and pinned) to aid smooth shifts...

There can be many reasons for poor chain life. Imho worn front rings is unlikely the reason here.

 

[mickle]

Cheap rings are pressed rather crudely out of sheet steel. It leaves a tooth which due to its narrowness and raggedy edge cannot support the chain very well. This is before the radical tooth profiling of shift ramps, lifting 'pins' and short teeth installed to aid under load shifting.

 

[Deleted member 1258]

Looks knackered to me, the inner ring doesn't looks to bad, but the middle and outer ring look worn, the middle ring worse than the outer. I haven't come across a case of chainring wearing out chain before, but worn chainrings won't help matters.

 

[mickle]

If you run a new chain on a knackered ring you'll knacker the chain.