Chain flapping noise after new drivetrain installed - Any ideas?

egroover

Esteemed Pedelecer
Aug 12, 2016
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579
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UK
Hi all, quick update, I tried a chain with one less link, no good, way too tight, so chain length is correct, 114 links, as originally worked out using calculator and same length as old chain.
I suspect it's a combination of new chain and existing chainwheel causing the chain suck. I think I'm gonna give it a few rides to see if it settles down before changing the chainwheel. it doesn't look to bad wear wise, but these 42t chainwheels are alloy compared to the bafang kit ones which are steel, so it will wear quicker no doubt. As mentioned, might switch to the stock 44t steel bafang I have new still in the box

Cheers all

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egroover

Esteemed Pedelecer
Aug 12, 2016
978
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UK
Very nasty. Why did you do all that? Hope you've fully recovered.
Yep, all recovered now thanks, but a couple of weeks off work in bed and a few months physio on and off at the time.
Damp solid chalk rutted farm tracks at 20mph on knobbly tyres is not a healthy combination, beware kids !
 

guerney

Esteemed Pedelecer
Sep 7, 2021
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Hi all, quick update, I tried a chain with one less link, no good, way too tight, so chain length is correct, 114 links, as originally worked out using calculator and same length as old chain.
I suspect it's a combination of new chain and existing chainwheel causing the chain suck. I think I'm gonna give it a few rides to see if it settles down before changing the chainwheel. it doesn't look to bad wear wise, but these 42t chainwheels are alloy compared to the bafang kit ones which are steel, so it will wear quicker no doubt. As mentioned, might switch to the stock 44t steel bafang I have new still in the box

Cheers all

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View attachment 56475
Is that the aluminium version of the Lekkie you got from AliExpress? And I thought the grooves on my steel chainwheel looked slightly asymmetric. Those spikes on your chainwheel look a bit knobbled at the ends.
 
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matthewslack

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Nov 26, 2021
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The drive side of some of those teeth looks very steep and a bit undercut. A gentle filing exercise might help.
 
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Sturmey

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Jan 26, 2018
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Hi all, quick update, I tried a chain with one less link, no good, way too tight, so chain length is correct, 114 links, as originally worked out using calculator and same length as old chain.
I suspect it's a combination of new chain and existing chainwheel causing the chain suck. I think I'm gonna give it a few rides to see if it settles down before changing the chainwheel. it doesn't look to bad wear wise, but these 42t chainwheels are alloy compared to the bafang kit ones which are steel, so it will wear quicker no doubt. As mentioned, might switch to the stock 44t steel bafang I have new still in the box

Cheers all

View attachment 56474

View attachment 56475
Looking at photos above, I think thats a narrow wide chainring. Every second tooth is narrow/wide and the wider outer chain link must go on to the wide tooth and the inner narrow chain link to the narrow tooth..

 
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egroover

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Aug 12, 2016
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guerney

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Sep 7, 2021
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No it won't.
I was really hissed off at having been sent a damaged chainwheel, when I'd ordered brand new and undamaged... said so to the seller, and he offered me a £2 refund. Reasoning that 1T...

I reckon they'll all look like that after a 100 miles
...might overall reduce chainwheel life only a tiny bit, I accepted the refund... but the seller then went and confirmed a return. So I noted that the seller's limited company address didn't match the ebay seller's address, and asked which address I should post the damaged item to, and told him that the product was insufficiently protected during transit, by a single layer of bubblewrap in envelope form. "How's that supposed to protect this chainwheel?", I asked. I also said a bunch of other stuff: BS about how the damaged tooth would damage the chain, leading to even more potentially catastrophic damage to the cassette sprockets and jockey wheels. I also said I'd leave a honest and highly negative review (I've never left anyone a negative ebay review, in all these years - I've been buying since 2007 and have a purple star 100% positive rating).

The seller then replied, asking me if I'd like a full refund without having to send it back. I said I was happy to post the damn thing back and wanted a full refund, at which point the seller provided a prepaid Royal Mail 48 mailing label, despite having said previously that he didn't provide mailing labels... then changed his mind about the return and provided a full refund. Voila! Free chainwheel! :)

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The seller shouldn't have:

1. Packaged this chainwheel so poorly.

2. If it was damaged beforehand, try to palm me off with a damaged product.

You'll never catch me selling anything on ebay lol, too many buyers like me about.

I don't get why the seller didn't just refund me £2, and left it at that.
 
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egroover

Esteemed Pedelecer
Aug 12, 2016
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579
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UK
Just to update, turns out the chain suck was down to a worn chainwheel. New one fitted today ( https://www.ebay.co.uk/itm/364294336249?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=0fqwmqzxtxi&sssrc=4429486&ssuid=Dst78JQnToG&var=&widget_ver=artemis&media=COPY ) and all is smooth and quiet. The old worn one didn't look too bad but a combination of that and a brand new chain was enough to cause the noise. I suspect the new chain might of settled down with the old chainwheel in time, but for the sake of £29.50 I know now that the whole drivetrain is new and the old chainwheel lasted 4k miles which considering I don't have a gear sensor fitted and it's alloy I'm okay with replacing every few years. I could fit the stock Bafang steel 44t one, but I scored a few KMC 114 link 9 speed chains cheap a while ago, they are perfect lenght for the alloy 42t chainrings, so I avoid adding links or buying longer chains, plus I get a lower gearing for knee crunching hills. And save a few grams in weight

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