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Chain Tension - Help needed!

birch1983birch1983 Posts: 124
edited February 2011 in MTB workshop & tech
I'm hoping someone with a little knowledge would be able to offer a little advice. I have a Carrera Vengeance Ultimate which I took to Sherwood Pines at the weekend. The bike performed brilliantly, however my chain seemed to spend a lot of time slapping against my frame through bumpy sections. I have a lizard skin on the bike to try and protect this area of the bike but would like to minimize the chains movement.

Do I need to shorten the chain to increase tension?
Is there a correct way or wrong way to do this? (Don't want to shorten the chain too much and cause other problems)
Should I fit a chain guide to the bike instead?

Help and advice would be really appreciated.

Thanks in anticipation of your response.
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Posts

  • cooldadcooldad Posts: 32,904
    Chain around big/big missing out the mech plus 2 links.
    I don't do smileys.

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  • birch1983birch1983 Posts: 124
    Is there a way of checking this though without having to split the chain to test?
  • .blitz.blitz Posts: 6,588
    You can get a rough approximation by shifting into the big-big combo and looking at the rear mech. If the chain is anything like the optimum length, the mech should be extended with the jockey wheels in line and horizontal.

    If the mech is not fully extended in the big-big combo you can shorten the chain.
  • cavegiantcavegiant Posts: 1,546
    This is a very common problem and I would not worry too much about it.

    getting a more heavily sprung rear mech (like saint) or lighter chain, switching to a 2x9 to get a shorter rear der will all help.

    Nothing will fix it. It is only a problem if the chain keeps falling off.

    chain guide brings chain closer to chainstay so may worsen it (but reduces throwing).

    really I would not worry.
    Why would I care about 150g of bike weight, I just ate 400g of cookies while reading this?
  • ride_wheneverride_whenever Posts: 13,279
    Best bet is get a better/stronger sprung rear mech. If shimano then the shadow mechs are less prone to it and sram ones seem to be better still.
  • .blitz.blitz Posts: 6,588
    Always surprises me just how much tension there is in a new mech of any kind.
  • nicklousenicklouse Posts: 81,520 Lives Here
    it happens, it has done for years.

    either spend lots of money or do as most people do. use it as it is untill it fails and need upgrading.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • birch1983birch1983 Posts: 124
    It's a Shimano 9sp Alivio rear mech if it helps.

    Being honest though I am now sick and tired of hearing the noise. If it wasn't far a lizard skin I dare say most of the paint would probably be gone from that area of the bike already. I need to do something to it.

    Is the best place to start as advised by Blitz.

    Maybe remove a section if required if appears out.

    If this fails replace derallieur.

    I am ever so grateful for all your help and comments so far.
  • .blitz.blitz Posts: 6,588
    If the mech is not fully extended in the big-big combo, the chain will be too slack in some other gears. The mech has a capacity which means it can only take up the slack for a certain range of gears.

    Most MTBs with three rings up front have a long cage mech, two rings use a medium cage mech and a single ring can use a short cage mech.

    Long cage mechs have a greater capacity than other mechs but at the same time they are physically bigger and can flap around in some gear combinations.

    A new mech of the same type will have a stronger (newer) spring but inevitably it will slacken off in time and the chain slap will return. If it's really annoying you, think about a single ring up front, a short cage mech, a good chain stay guard and a chain guide.
  • cavegiantcavegiant Posts: 1,546
    If the noise is irritating, wrap an inner tube around it (what I do)
    Why would I care about 150g of bike weight, I just ate 400g of cookies while reading this?
  • cavegiantcavegiant Posts: 1,546
    Oh, and if that doesn't work getting an SLX deraliur will help ALOT.
    alivio is not really MTB stuff.

    If you do not use your big ring, going 2x9 and getting a mid length SLX will help significantly more.
    Why would I care about 150g of bike weight, I just ate 400g of cookies while reading this?
  • birch1983birch1983 Posts: 124
    When I get home tonight I shall see how the chain sits when in the big/big position and let you know the result.

    Thanks so far to everyone, I really appreciate your help!
  • .blitz.blitz Posts: 6,588
    Just take it easy shifting into the big-big combo in case the chain is too short and the problem lies elsewhere
  • birch1983birch1983 Posts: 124
    Ok, well I've got home and just put the bike in big/big. Chain sits as below:

    31012011062.jpg

    From the advice given I'd be inclined to say this chain is under too little tension. Would you guys say the same or?
  • Chunkers1980Chunkers1980 Posts: 8,035
    Looks fine to me. Shouldn't really use that gear depending on how your chain line is though.

    Now a pic of small/small would help, just to be sure.
  • birch1983birch1983 Posts: 124
    Small/small as requested.

    31012011063.jpg

    I'm still not so sure.

    Could it do with being under more tension?
  • Chunkers1980Chunkers1980 Posts: 8,035
    Nope - all looks about right. You'll never get less tension than that, and you never really use that gear unless you get caught out.
  • dilemnadilemna Posts: 2,277
    edited January 2011
    birch1983 wrote:
    Ok, well I've got home and just put the bike in big/big. Chain sits as below:

    31012011062.jpg

    From the advice given I'd be inclined to say this chain is under too little tension. Would you guys say the same or?

    O M G! Lordy lordy - a good way to prematurely wear out your bike chain, chain rings, free wheel and deraillieur :roll: . Use your gears properly! Why isn't your bike chain on the middle ring at the front and middle of the cassette? I suggest you take a look at SheldonBrown's gear calculator so see where you favourite gears are as several will be duplicated and use the ones that DO NOT excessively stretch the chain.

    DO NOT use the smallest chain rings with smallest rear sprockets or correspondingly large chain rings with the large rear sprockets. Well you can but your bike transmisiion will quickly become knackered plus you won't be using your gears as efficiently as possible.

    Use smallest front chain ring with larger rear sprockets and largest chain ring with smallest rear sprockets. Simples really :roll: . You can use a chain stay protector but if your are using your gears properly you shouldn't need it. Even with an Alvio deraillieur I am sure the spring is more than strong enough. What will knacker it though is constantly being stretched to max or with no tension on it as your pics clearly show.
    Life is like a roll of toilet paper; long and useful, but always ends at the wrong moment. Anon.
    Think how stupid the average person is.......
    half of them are even more stupid than you first thought.
  • birch1983birch1983 Posts: 124
    You mean more tension not less?!?!?!

    Even out of those gears such as big front/mid rear it still slaps the frame. :(
  • birch1983birch1983 Posts: 124
    dilemna wrote:
    O M G! Lordy lordy - a good way to prematurely wear out your bike chain, chain rings and deraillieur :roll: .

    Care to expand? Now you've lost me?!?!?!? :?
  • Chunkers1980Chunkers1980 Posts: 8,035
    It will.

    Through any rough ground you can go up to the biggest front to stop it a bit. But like peeps have said it is not that greater mech in the first place.

    Look at the small/small pic - if the chain was sagging then it may have been the mech, but it's not, so really it's just the fact it's alivio.

    If you're feeling flush a Deore might be in order, it will improve things and allow you to run a better cable line into the mech without all hat loop.
  • Chunkers1980Chunkers1980 Posts: 8,035
    Birch - search cross chaining.
  • birch1983birch1983 Posts: 124
    Thanks Chunkers. Just done a search. I've been abiding by those rules :D
  • Andy!Andy! Posts: 433
    dilemna wrote:

    O M G! Lordy lordy - a good way to prematurely wear out your bike chain, chain rings, free wheel and deraillieur :roll: .

    try reading the 1st 4 posts :wink: :roll:
  • dilemnadilemna Posts: 2,277
    birch1983 wrote:
    dilemna wrote:
    O M G! Lordy lordy - a good way to prematurely wear out your bike chain, chain rings and deraillieur :roll: .

    Care to expand? Now you've lost me?!?!?!? :?

    I did at some length. Explain to me what I have tried to advise. You did ask for advice didn't you?
    Life is like a roll of toilet paper; long and useful, but always ends at the wrong moment. Anon.
    Think how stupid the average person is.......
    half of them are even more stupid than you first thought.
  • dilemnadilemna Posts: 2,277
    Andy! wrote:
    dilemna wrote:

    O M G! Lordy lordy - a good way to prematurely wear out your bike chain, chain rings, free wheel and deraillieur :roll: .

    try reading the 1st 4 posts :wink: :roll:

    I did. I also looked at the pics the OP has submitted of his bike transmission. My advice remains the same, perhaps you should try reading it. His bike chain length appears ok and I should imagine so is the deraillieur unless he's totally shagged it by frequently riding his bike in the gear configurations he shows in his pics, in which case, his bike will need a new deraillieur. I would suggest he gets a bike shop to fit the replacement so at least it will be set up properly, one would hope.

    So please Andy! what is your advice? Don't be coy or shy :wink: .
    Life is like a roll of toilet paper; long and useful, but always ends at the wrong moment. Anon.
    Think how stupid the average person is.......
    half of them are even more stupid than you first thought.
  • Andy!Andy! Posts: 433
    because what you wrote appears to assume he is riding his bike in the big-big format and are telling him how to use his gears.

    The pic of big-big is in response to someone telling him to try it to look at chain length. He doesnt ride like that. :roll:
  • Andy!Andy! Posts: 433
    dilemna wrote:
    Andy! wrote:
    dilemna wrote:

    O M G! Lordy lordy - a good way to prematurely wear out your bike chain, chain rings, free wheel and deraillieur :roll: .

    try reading the 1st 4 posts :wink: :roll:

    I did. I also looked at the pics the OP has submitted of his bike transmission. My advice remains the same, perhaps you should try reading it. His bike chain length appears ok and I should imagine so is the deraillieur unless he's totally shagged it by frequently riding his bike in the gear configurations he shows in his pics, in which case, his bike will need a new deraillieur. I would suggest he gets a bike shop to fit the replacement so at least it will be set up properly, one would hope.

    So please Andy! what is your advice? Don't be coy or shy :wink: .

    Bit in bold - he is not riding it like that. he only put it into that configuration to see if the chain length was correct. Which everyone else understood.
  • nicklousenicklouse Posts: 81,520 Lives Here
    lots of videos to show what happens

    http://www.youtube.com/watch?v=AZQf1bduGYs
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • Andy!Andy! Posts: 433
    nicklouse wrote:
    lots of videos to show what happens

    http://www.youtube.com/watch?v=AZQf1bduGYs

    that makes me want to go single speed!
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