Crunching chainline noise

Bought a brand new chainset about 2 weeeks ago, stuck it on; no problem. Bought a new chain today, installed it and there's a very strange, crunching noise coming from the driveline. Chain is identical (Izumi) and just to be absolutely sure, took the new chain off, stuck the old one on and guess what, the noise is gone. The noise only seems to happen when I put down pressure (e.g. when I'm out of the saddle or going uphill). I have a strange theory but I just need someone to agree/disagree with me on this. I think that the chainring was brand new and the initial groves and wear that it developed was from the worn chain so now that it's a brand new chain, the wear doesn't match and so I just have to wear the chain in.

Any opinions?

Not sure why the crunchy sound.

But why change the chain that's only two weeks old?

Chain too tight / chainring eccentric, is what I'm voting for.

But why change the chain that's only two weeks old?

Chainset is 2 weeks old, but I'm guessing the chain was older?

I would also guess chain too tight?

Chain has been tested on various tension yet it still makes noise.

The previous chain was about half a year old and quite worn.

Also, forgot to mention but this is a fixed gear setup.

Your theory will be at least partially correct. Though I would have thought that worn chain with new ring would run as rough as new chain with a worn ring.

It's not tension related as if it were it'd make the noise when the bike was in work stand or rear wheel lifted but it only does it under pressure so IMO it's more of a meshing problem.

I find roller chains (which I think even the cheapest izumi are) run rougher than non roller chains. Some of the roughness may die down as your chain and sprocket become used to one another but it might never be as smooth as a cheap KMC would run.

The only unusual noise upon installing the new chainset was a strange sloshing sound that I've never experienced before (it essentially sounded like the there was too much lube so I tried a few variations yet it still persisted) which I assume was caused because by the worn out gaps between links. I think that since we know that it's the chain, I'll do a bigger ride tomorrow (30 or 40 miles should do it) and see if the noise persists or if it eases down, I can only assume that the driveline has gotten accustomed to the new chain.

I'll update the thread once there's some kind of news

How old is the cog? If you've put a new chain on a worn cog it can make a crunching sound.

Can't remember exactly but I would guess no older than April. I also considered it but it doesn't look particularly worn at all. However, I am a courier so all my components seem to wear out ridiculously quickly.

If the noise persists after tomorrow's ride, I'll stick on a new cog.

This is why between all my bikes it's a rare month that something isn't getting a new chain.

Spend a tenner every couple/few months on replacing your chain and your cogs and sprockets will live a lot longer.

In my experience the cog doesn't even have to be visibly worn.

Well, it turns out that kirkov was correct. The cog was the problem.
Swapped it out for a different one and the noise is gone. Probably should have thought of it prior to making this thread. Thanks to everyone for their input and I'll definitely keep an eye on my chain from now on.

I fitted an izumi chain with new sprocket and chainring. it always grinded, even after a few hundred miles it carried on, so I went back to a new kmc 510 and forgot about the izumi.

I wouldnt change chains every few months just to make your drivechain last longer. run a drivechain til the chain snaps or theres no teeth left, then replace the lot.

A cog interlaces directly with other cogs. you generally shouldnt even have cogs on your bike.

I wouldnt change chains every few months just to make your drivechain last longer. run a drivechain til the chain snaps or theres no teeth left, then replace the lot.

Even taking into account you meant "drivetrain", this is absolute bollocks.

constructive critisism only plz.

I wouldnt change chains every few months just to make your drivechain last longer. run a drivechain til the chain snaps or theres no teeth left, then replace the lot.

Constructive criticism: Chainrings last longer than cogs which last longer than chains. Riding them all to failure is (I guess) an option if you're confused or disinterested. It's a waste and as advice... it's bollocks.

If you replace your chain when it's at 75percent-dead, cogs every few chains and chainrings every blue moon you'll save cash and avoid snapping chains.

Running your drivetrain into the ground makes no sense from either a financial or mechanical point of view.

Do you really need that spelling out?

Not to mention that deliberately waiting for the chain to snap, is one way to ensure a visit to A&E and/or the dentist.

Constructive advice only plz.

swings and round abouts I suppose. I'll just change drivechain every year or 2 rather than messing about with stuff more often.

No it's not.

It's not swings & roundabouts, it's stupid and dangerous.

And it's not a fucking drivechain.

A year from a chainring and cog is bollocks.

A half decent chainring could easily be costing you upwards of £50, a cog £10-20, I'd expect a cheap KMC chain to be completely unusable before the year was out so lets say £20 for a chain. So a conservative £80 - 90 a year as opposed to 4 or 5 x £5 for a KMC 510 every few months = £20-25. So almost 1/4 the cost plus you have a drivetrain that works, smoothly, doesn't drop chains and doesn't fail at some unknown point putting you over the bars or worse.