Chainline noise - videos/photo

I know there are a load of chainline threads and i know how to go about shifting the chainring over using spacers but I'm not entirely convinced that all the noise coming from my bike is from the chainline, I think the sprocket may be part of the problem too. To cut a long story short here's what happened:

1. I wanted to lower my gear to go up the massive hill home
   
2. Bought 20t sprocket, went to fit it but cheap hub thread was stripped.
   
3. Bought System-Ex hub, fitted 20t now the bike sounds like a jet engine!
   
   

The chainline really doesn't look far enough out to generate the amount of noise coming from the back, do you think the 20t may be all out of shape or something?

Check out this pic:

Does it look out by a mile, I've spent so long looking at it I'm going blind.

Also a couple of videos with the noise:
http://gallery.me.com/tfrancis#100104/chainline-1
http://gallery.me.com/tfrancis#100104/chainline-2

Thanks for any help,
roon
http://www.fixedgearwales.co.uk

oil the chain in it.

I cleaned and oiled the chain when I refitted the wheel so I don't think it's that, more oil maybe?

What sprocket did you get? If it was a cheapo one there may be poor quality machining, meaning the chain will not engage with the teeth as smoothly.

on a serious note though, when i fitted a new cog to my rig it was noisy, it seems that it needed time to bed in properly since it is now as quiet as a mouse.

other than that, check your chainline properly by measuring it to be sure it isnt that.

It's a no-brand, i tried using a screwdriver and hammer to get the lockring off earlier to try a different sprocket but no luck, I'll need to use the proper tool in the shop on the weekend :-p

I've been riding it for over a week. How can I properly measure it? Centre of down tube to centre of chainring? What about the back?

It's a no-brand, i tried using a screwdriver and hammer to get the lockring off earlier to try a different sprocket but no luck, I'll need to use the proper tool in the shop on the weekend :-p

you need a mahhhusivvve punch and a big hammer.

but I think the sprocket may not (as Pifko said) engage well with the chain. Sometimes low quality cogs have cheaply cut teeth which don't set well into the chain links and create a little noise as they hit the linkages.....
i presume you bought a cheap 20t from ebay? There are some on there at the moment for as low as a fiva which are of dreadful quality, the teeth are hardly even half deep as they should be.

Check the length of the teeth on the sprocket, if they don't set into the chain properly and hardly have any length to grip them it's worth investing in a proper sprocket.

maybe post some photos of the sprocket?

I got it from my lbs, it was the only one they had and I was getting impatient cause they could get hold of a 19t. I'll try a load more oil, then some chainring spacers then I'll be taking the 20t back I think.

oh and the chainline looks fine.....i think the problem is in the low quality rear sprocket

My fixed gear makes pretty much exactly the same noise. How crap are the £8 sprockets from Condor? Do I just need to HTFU and wait for it to wear in or will I need to adjust the chainline (which is about 5mm out)?

Sorry for the thread hijack!

I just put loads of oil on and the noise is much less for now. But the sprocket is deffo shitty.

i get a lot of noise off a dura-ace cog. it's teeth have much sharper shoulders than the surly that got nicked along with the wheel, which was whipser quiet.

I have a 20t andel sprocket which is good as new. £10 if you want

thanks for the offer but if anything I'm gonna try and swap it at the shop for a 19t even though they are having trouble getting one.

fair enough... pm me if you do want it.... will prob sit at the bottom of the toolbox for a few more months at least.

My fixed gear makes pretty much exactly the same noise. How crap are the £8 sprockets from Condor? Do I just need to HTFU and wait for it to wear in or will I need to adjust the chainline (which is about 5mm out)?

Sorry for the thread hijack!

I have a Condor branded one, £12 reduced from £20 though, and I'm happy with it.

Condor branded one are decent, they're £15 I think.

Nah this isn't one of their branded ones, this one is sold in a condor packet but it's plain. It's one of the ones they've got on their rack at the back of the shop for £8.95...

Your chainline looks to be a few mm out....if you see the chainset teeth, the chain should be central, looks to be over to one side. Cannot see the sproket, but the chain should, again, be central - I suspect it will be over to the opposite side as the chainring. Usually the cause of this kinda issue - you can geta similar noise if you use a 1/8th chain on 3/32 chainset and sprocket - but of chainslap as such.

chain too tight?

I reckon it's the hamster running around inside it

seriously, could that sound be a BB issue?

it's deffo from the back so not bb related. It's a mix of chainline being out and a crap cog. It sounds much better now that I've soaked it in oil.

I have a very similar, if not the same problem with mine, recently changed to 1/8 instead of 3/32 which i'm thinking is what caused the problem, i didn't change the cog or the chainring