Really loud chain

[rtnicho]

Greetings
I've just changed my son's back cog from a 16T to a 15T in preparation for his move into the next age category. After doing this there is a really excessive amount of noise coming from the chain. I tried 2 other 15 T cogs and oiled the chain: No improvement. Chain is an Izumi black and silver. Cogs were an assortment that I had in my tool box but don't look worn. Chainset is Miche Primato Advanced 48T.
Say What?

[foo on patrol]

Are they both the same width as in rear to face side and not having a slightly narrower spacer on the rear? How does the wheel roll and have you put the chain on the correct way as some have a certain way for them to sit? Did you put a half link in at all or is the chain the same length?

Foo

[rtnicho]

Thanks Foo. It's possible that the cogs could be different widths, I'd have to check, but it seems unlikely that all 3 15T cogs I tried vary that much from the 16T I had on it previously (or the 17T I have on the other side of the flip flop). The wheel spins fine. I haven't made any changes to the chain (didn't remove it).

I'm thinking that it could be a subtle chain line issue which only materialises on a smaller back cog.

[P!N20]

If your 16T sprocket, chainring and Izumi chain have been wearing each other out for a while, swapping out the cog means things aren't going to mesh quite as well, resulting in the noise.

Your options are; if you think the new 15T cog hasn't been worn much, get a new chain. The problem here is the chainring will probably start making the noise. If that's a problem, hello new chainring.

Or, you could just put up with the noise which will eventually disappear as the cog wears in.

I've had this problem when I've put new chains on worn cogs/chainrings. Most of the time I've just kept riding it until the noise disappears. But I tend to ride things into the ground

I might be wrong, but it seems the most likely explanation. Chain line would have to be a fair way out to start making a noise, I would have thought.

[rtnicho]

Thanks P!N
Could be a wear mismatch.
But chain has less than a year of junior's riding wear (not a lot of watts) and the back cog has been swapped pretty regularly between the 16T (training) and 17T (racing), so the 16T and chain wouldn't have meshed. The chainring is even newer.
It won't hurt to chuck a new chain on it and see what happens tho. Cheers

[ironhanglider]

I started track racing on an old bike. It didn't have one of them new fangled roller chains, it had a proper block chain

which sounded a lot like this.



I lamented the noise and the lack of ability to launch a sneak attack etc. but an old timer pointed out that it was a good noise. It is when it suddenly goes quiet that you have a problem.

Cheers,

Cameron

[Derny Driver]

Thats pretty much normal for track bikes.
I wouldnt worry about it.