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Chain and sprocket change


Phooey
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Ok, so I have decided that I must be too thick to do bike maintenace!


As some of you may know, I had to buy a leverage bar to get the front sprocket loose. So this morning, having the morning off work and the sun shinning I decided to get the job done.


With front sprocket cracked I split the chain. No problems and starting to feel good. I removed the rear wheel, axle came out easily and rear sprocket off once I found a way of holding it to loosen the nuts. Next time I'll be cracking them before taking the wheel off!


So front and rear sprocket changed, old chain off ... next thing to do is replace the rear wheel. Bit fiddly but managed to get the axle back in and castleated nut and washer back on. Loosened the chain adjuster to give loads of slack for the new chain and got the new chain on and joined with the greased O rings and plate. Joining was harder than I thought ... not as strong in the hands and arms as I used to be :(


Anyway, all went well ... just left with adjusting the chain. Now here is my problem. After adjusting the chain I seem to have a tight spot and a very slack part. Worse than the old chain and sprocket set :(


If I adjust as I do for normal adjustments I get part superslack like racing slack and a tight spot that barely moves!


I started the bike and put it in 1st to see if the rear wheel looks like it is running true just incase I have totallymissread the adjusting marks :oops: and the clanking noise is horrendous! Chain obviously too loose but I can't take up the slack without making the tight spot even tighter and risk breaking the chain. The tight spot is close to the joining link!


What have I done wrong?

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Hmm - doubt you'll break the chain on the tight spots. You've not got any packaging material/detritus left on any of it have you?


This may be a really, really bone question but did they send you the correct pitch chain and sprockets? having a mismatched set can cause all sorts of weird things to happen.


I'd take the link apart and give the whole lot a good wiggle around in case you've got sticky links to free them up. If that didn't work I'd start measuring the link-link distances to check it's not an iffy chain.

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Hmm - doubt you'll break the chain on the tight spots. You've not got any packaging material/detritus left on any of it have you?


This may be a really, really bone question but did they send you the correct pitch chain and sprockets? having a mismatched set can cause all sorts of weird things to happen.


I'd take the link apart and give the whole lot a good wiggle around in case you've got sticky links to free them up. If that didn't work I'd start measuring the link-link distances to check it's not an iffy chain.

 

No debris or bits that shouldn't be there. I checked the sprocket and link alignment ... on front and back ... and all appears ok.


Just to make sure I also checked the rear sprocket with a make shift tool to check alignment and all appear to be ok to.


I know that something must be out of alignment for the tight spot but can't see it.


:(

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if its a tight spot in the chain then its not an alignment problem as that would create a tight spot in the same place regardless of where wheel is but im assuming the tight spot is traveling as you rotate the chain might just need working in or could have a link pinched to tight when chain made in factory

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if the tight spot on the chainis in the same links as chain revolves around the sprockets then it sounds like a faulty chain to me if the tight spot is always at the bottom or top of the chain even after turning it round a bit then its alignment,dont always rely on the markers on the swinging arm take a measurement from centre of swinging arm pivot bolt to centre of rear wheel bolt and each side should measure the same

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In my 15 years of tinkering with bikes and changing loads of chains I have NEVER seen one that has tight spots when new especially to the extent that your talking about!


what make of chain did you get?


I wouldn't be happy to run that and once run you may find that the supplier may not take it back!

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something is definitely amiss and its hard to say without looking


you didnt rivet the link too tight causing it to keep kinked as it comes over the front sprocket?

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No Stu, I have checked that. The links go over the front sprocket nicely. Everythin I have checked seems to be fine!


My mate who used to be a bike mechanic says it it fine and will settle down! I'm at the stage where I don't know what to believe.

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everything ..................on the bike not personal ones :lol:


just a few snaps showing the tension (tight and slack) and stuff just to see if anything stands out etc

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Ok what's the best way to upload a vid. I have been trying for hours and it is taking so long I assume something isn't working. A 27 sec vid on my phone has been saying 'The upload is currently in progress' for about 2 hours now!

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I thought it was shit your pants slack - that's not so bad! Is that before or after you took it for a spin?


I did notice at around 10 seconds (when you go from tight to slack) there's a section of your rear sprocket that doesn't appear to have any grease/oil marks on - I would expect to have uniform contact all round the sprocket - no grease could indicate the rollers aren't sitting correctly in the sprocket.


Can you have a shufti and let me know if I'm seeing things?

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Trick of the light Mr Fro ... Grease all the way round the rear sprocket. I haven't taken her out at all yet. Was a little concerned that something was wrong. Maybe it's my inexperience then, because I assumed/expected that a brand new chain and sprocket set would give uniform, or nearly uniform, tightness all round.


Thanks.

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Just my two pence worth, but could the drive shaft (not sure what its called, but the bit that the front sprocket is attached to) be bent?


It's the only way I can see you having a tight spot on a new chain and sprockets, especially if everything is okay at the rear.

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