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Chain tension problem

~Adam~~Adam~ Posts: 65
edited March 2008 in MTB workshop & tech
I recieved my new sprocket today (30T) and fitted it straight away(16T free wheel), got the tension right, made sure the wheel was in-line and all the usual.

When i turn the cranks the chain gets tighter then as the crank arm gets to the oppesite side it slackens off. its not just a slight tension change either, it gets way too tight at one point.

Can anyone give me any advice as to why this might be happening? And is there anything i can do to stop is happening?

Any help appreciated!

Posts

  • nicklousenicklouse Posts: 81,520 Lives Here
    your chain is too tight.

    it is a common problem.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • ~Adam~~Adam~ Posts: 65
    well i have tried making it slacker but when it gets to a certain point it is way too slack :?

    i have tried a few different tensions but it gets way too tight and slack at certain points
  • dave_hilldave_hill Posts: 3,877
    - bent bottom bracket axle
    - chainring out-of-round or mounted incorrectly
    - chainring manufactured wrongly
    - unevenly worn chain
    - problem with your rear sprocket

    could all contribute.
    Give a home to a retired Greyhound. Tia Greyhound Rescue
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    JayPic
  • probably incorrectly mounted, loosen off bolts half a turn, rotate till tight, whack with a hammer, keep turning to tight and continue until it is centred. From sheldon brown.
  • ~Adam~~Adam~ Posts: 65
    probably incorrectly mounted, loosen off bolts half a turn, rotate till tight, whack with a hammer, keep turning to tight and continue until it is centred. From sheldon brown.

    whack what with a hammer? sorry if its a stupid question, and when you say "whack" how hard is a whack? dont want to be breaking anything :lol:
  • nicklousenicklouse Posts: 81,520 Lives Here
    ~Adam~ wrote:
    well i have tried making it slacker but when it gets to a certain point it is way too slack :?

    i have tried a few different tensions but it gets way too tight and slack at certain points

    you may have incorrectly fitted something then.

    Like i said a small change in tension is normal.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • ~Adam~~Adam~ Posts: 65
    Well i turned the crank until the chain was realy tight then moved the wheel forward until the chain was at a reasonable tension, how it should be, then when i turn the crank to the oppesite side the chain is sagging way too much.

    If i have mounted something incorrectly can anyone geve me advice on how to fix it?

    What 'ride_whenever' said sounds promising but im not sure what you mean when you say "whack with a hammer" :?

    Thanks for your help so far.
  • nicklousenicklouse Posts: 81,520 Lives Here
    pictures.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • ~Adam~~Adam~ Posts: 65
    I dont have a camera :roll:
  • nicklousenicklouse Posts: 81,520 Lives Here
    then take the bike to someone who can see what you have done wrong (if you have).
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • ~Adam~~Adam~ Posts: 65
    Well the only place near me is halfords.... i dont fancy my bike getting looked at by kids :lol:

    Im going take everything off and re-mount it all and see where that gets me... again :roll:

    Thanks for your help
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