Rattly noises

[juliet]

Yesterday I (finally) changed my 'orrible old grubby worn-out chain for a lovely sparkly new one.  When cleaning the chainring and sprocket I noticed that they were a fair bit bashed up.  Riding it last night I got a rattly noise which I *think* is coming from the chainring.  I'm about to check that the chainring bolts aren't loose, but I think that the noise is from the nice new shiny chain rattling on the chewed-up chainring teeth.

Questions:
a) is this likely to be the case or am I making stuff up?
b) is this dangerous?  I can't really afford a new chainring & sprocket atm so was intending to keep riding on the existing ones for the summer (bike is going to be resprayed etc while I'm away over the winter, so that seems like the right moment to replace other things as well). But if it's going to cause me dangerous-type trouble then I'll rethink.

[rogerzilla]

Fixie chains are prone to noise, especially the full-bushing variety.  A worn chainring rarely causes slippage, but a worn sprocket does, so you might want to think about replacing that.  Some people run the whole lot - chain, sprocket and chainring - into the ground and replace the whole lot together.

A SRAM PC-1 runs quieter than most 1/8" chains (if you're using 1/8").

[Greenbank]

I just wear headphones. That also solved the annoying squeaking M520 pedal and the rattly GPS mounting (I've lost the seal on the battery door).

[Ian H]

Mine is a bit noisy unless I cover it in gloop. A fresh application of off-road oil silences it, but the noise returns long before the chain is dry. It's all 1/8" except the chainring.

[juliet]

Mine's all 1/8 except the chainring as well.  I could try adding a bit more gloop, but given the current nice dry conditions I don't really want to bring forward the moment when it all gets 'orribly grubby again & comes off all over my legs.

The chainring is more bashed up than the sprocket, so if a bashed chainring is likely to be OK I'll go for "running the whole lot into the ground".  Like Greenbank I wear headphones 90% of the time (i.e. when not riding with someone else) so it doesn't actually *bother* me as long as it's not anything that's going to lead to me doing myself a mischief   It's only got to do another 4 months. 

Thanks!

[border-rider]

Mine's all 1/8 except the chainring as well. 

1/8 chains on 3/32 rings can be a bit rattly.  1/8 is often more rattly anyway. 

If it's a constant sort of rattle, rather than a  percussive cracking or banging, it's likely fine.

[juliet]

Constant rattle, a bit worse when I start up (which I'm guessing is when it's most likely to put pressure on the lack-of-good-fit, as it were). 

I shall have another good listen next time I'm somewhere quiet.

[Ian H]

If it's the chainring you could turn it round. If the cog has developed obviously hooked teeth* there's really nothing to do but throw it away.


* There'll be a constant 'thrum' noise as the cog tries to carry the chain round itself. With the chain slightly slack you can see the effect.

[andygates]

On mine, a clean tight chain produces a 'grobbly' sort of noise, like a thrum with a mouth full of marbles.  Slacking the chain off a tad and using a gloopy lube resolve this.

You can eyeball the chain where it enters and leaves the sprocket and chainring, and see if it's sitting square.  As long as it is, all is well.

[giropaul]

Inmy experience the cheaper the chain the quieter it seems to be.

I had a terrible (and expensive) time with a track bike some years ago. I replaced a new record bracket before I found that the "kieren" quality chain would not  tolerate any tiny deviation in chain line before making its objection loudly heard.

I eventually twigged when I found that it was better with old Campag hubs  than with Dura-ace - the latter having a slightly narrower chain line.

[teethgrinder]

It sounds to me as if your whole transmission is worn. Your old chain was as worn out as your chainring and sprocket. Is it quite loud?
And was the old one quiet? If the answer to those is yes, then I'l bet that's what it is. I'd put the old chain back on or you'll just make the new one as worn out as the old one, very quickly.
I use a Park Chain checker to test my chains. I mainly bought it for my mounyain bike, which has a very expensive transmission. The chain checker cost me £20. Maybe not worthwhile for a low mileage fixer, but it is for my mountain bike.

[Air Dancer]

Constant rattle, a bit worse when I start up (which I'm guessing is when it's most likely to put pressure on the lack-of-good-fit, as it were). 

I shall have another good listen next time I'm somewhere quiet.

A good heave from the dark recesses of your lungs to raise the phlegm can work wonders.

Seriously though, wot toothy said.

BBBBBBBBBB do something similar for less than a fiver.