Chain transfer to Granny ring on front cogs

-liam-
-liam- Posts: 1,831
edited December 2008 in MTB workshop & tech
Merry Christmas.

Quick query.

When changing down to the small cog on the front chainset if the chain is under tension, the front mech struggles to move the chain over..I just have to release the pressure on the pedals for a split second and mech then shifts over and takes the chain with it onto the Granny ring.. Is this possibly just a worn/weak spring on the front mech as it is clearly being defeated by the tension in the chain.

Chainset is a deore hollowtech. Front mech is also deore and the stop is set pretty much as far back as the mech can travel.

Comments

  • Not sure about springs and stuff but it's always a good idea to ease off on the pedalling while shifting anyway. With less tension on the chain during shifting your drivetrain will last a lot longer.

    Shifting will sound better too and folk won't look round to see who's torturing their bike :wink:
    More freerange chicken than Freeride God
    Bighit , 5 , BFe
  • -liam-
    -liam- Posts: 1,831
    yeah I know mate but sometimes its not always possible eh?. Thanks anyway ;)
  • johnsav
    johnsav Posts: 775
    slack the cable off and adjust your limit screw mate. then set the cable tension again.
  • supersonic
    supersonic Posts: 82,708
    Have to say, prob is probably shifting under pressure. Ease off.
  • dave_hill
    dave_hill Posts: 3,877
    Try to pre-empt shifting down so that you don't have to do it while the chain's under tension.
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  • stumpyjon
    stumpyjon Posts: 4,069
    How old is the chain / chain rings? Has this started to happen recently. May be a sign of stretch / wear meaning the chain doesn't release as smoothly as it did when new. As the others said, too much pressure will prevent shifts.

    There are very few times when you should need to shift whilst hammering the pedals. It's down to technique and anticiapting the need to shift in advance. If you can improve this your riding will get better and your drivetrain will last longer.
    It's easier to ask for forgiveness than for permission.

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  • Anonymous
    Anonymous Posts: 79,667
    i find i need to take the pressure off to shift to the big ring too, theres nowt wrong with the drivetrain, im an expert gear fettler, its just the way things are.

    itll shift when i dont take the pressure off but it is a millions times smoother and quieter if i do
  • -liam-
    -liam- Posts: 1,831
    Thanks for the replies chaps.

    1st off, its the front chainset not the rear cassette (for the benefit of sheepsteeth)

    The entire chainset is no more than 4 months old.

    It wasn't this way when I had an 8 speed drivetrain on it.

    I'm not talking proper full on pedal pressure up a steep incline, I just talking mild pressure.
  • Anonymous
    Anonymous Posts: 79,667
    im not the one who doesnt understand the problem, i was pointing out that you need to take the pressure off to change front gear in general. both to the bigger and smaller rings.
  • -liam-
    -liam- Posts: 1,831
    im not the one who doesnt understand the problem, i was pointing out that you need to take the pressure off to change front gear in general. both to the bigger and smaller rings.

    Thats fair enough mate. My misunderstanding of what you was saying.

    I fully understand that we need to release as much pressure as is practical. However, if we all needed to fully release pressure to change a gear when climbing a steep hill, non of us would ever make it to the top. You also can't gain enough momentum at the bottom of a climb in the granny gears to get over the top so it is obvious that there is to be some changing of gear when the chain is under tension.

    The reason for asking is simply because I know it has not always been this way and I have adjusted to front mech. I'm also fully aware of how to ride a bike thanks ;)
  • Anonymous
    Anonymous Posts: 79,667
    how clean is your front cable? they often get filthy quicker than you think, the rsistance in the cable could be enough to slow your front mech down
  • dombo6
    dombo6 Posts: 582
    This is completely normal.
    Spring of the front mech is not strong enough to shift the chain when under pressure so, as others have said, ease off pedalling slightly as you shift to "loosen" the chain. Reason you notice it more on shifting to the granny ring is that you likely want to do this when pedalling up a hill that suddenly got much steeper, hence more pressure on the pedals just to keep going.
    Changing up to the bigger ring is not the same problem as when you do this you are probably close to spinning out so there is less pressure on the chain.
  • -liam-
    -liam- Posts: 1,831
    how clean is your front cable? they often get filthy quicker than you think, the rsistance in the cable could be enough to slow your front mech down

    Fitted brand new xtr cables about 6 weeks ago. Clean as.
  • Anonymous
    Anonymous Posts: 79,667
    is it a different chainset?