Chain coming off

Coxy_UK
Coxy_UK Posts: 297
edited August 2011 in MTB workshop & tech
A couple of times recently the chain has come of at the front. It has happened in both the large and middle ring under little or no load. The gears appear all correctly set up.

The bike is pretty new, hit the trails maybe 10 times on it so far.

Could it be that the rear derailler needs more tension? Or other ideas?

Bike is a Canyon Nerve XC 9.0

Thanks
_______________________________________________________________________________________
Tides of sin draw tighter and brighter, hours become heavier and weighted, and the shadows smile...dark and wild.
<font color="blue">My Stumpy FSR Pic 1</font id="blue">
<font color="red">My Stumpy FSR Pic 2</font id="red">

Comments

  • nicklouse
    nicklouse Posts: 50,675
    how is it coming off? inside? outside? how does it come off the middle ring?
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • Coxy_UK
    Coxy_UK Posts: 297
    On the large ring it came off on the outside. From the middle it came off inside, past the small ring, though only half off as i stopped immediately and i lifted the rear wheel and turned the crank slowly and it went back on.
    _______________________________________________________________________________________
    Tides of sin draw tighter and brighter, hours become heavier and weighted, and the shadows smile...dark and wild.
    <font color="blue">My Stumpy FSR Pic 1</font id="blue">
    <font color="red">My Stumpy FSR Pic 2</font id="red">
  • supersonic
    supersonic Posts: 82,708
    Is the front mech the right height and angle? Limit stops set?
    GT ZASKAR CARBON TEAM

    VOODOO CANZO

    Come and see me at https://www.facebook.com/biketyke/
  • Coxy_UK
    Coxy_UK Posts: 297
    yeah and gears work properly, nice and smooth
    _______________________________________________________________________________________
    Tides of sin draw tighter and brighter, hours become heavier and weighted, and the shadows smile...dark and wild.
    <font color="blue">My Stumpy FSR Pic 1</font id="blue">
    <font color="red">My Stumpy FSR Pic 2</font id="red">
  • diy
    diy Posts: 6,473
    check the chain length is correct.
    Guide to cheap bike lights Turbo Trainer Vids Play list
    Stretching & Workout Vids
  • Coxy_UK
    Coxy_UK Posts: 297
    Well it's been working perfectly since new until the last ride.
    _______________________________________________________________________________________
    Tides of sin draw tighter and brighter, hours become heavier and weighted, and the shadows smile...dark and wild.
    <font color="blue">My Stumpy FSR Pic 1</font id="blue">
    <font color="red">My Stumpy FSR Pic 2</font id="red">
  • TuckerUK
    TuckerUK Posts: 369
    I'd guess a sticky or even kinked link.
    "Coming through..."
  • dennisn
    dennisn Posts: 10,601
    My vote goes to either out of adjustment or poor adjustment. Which are basically the same thing. Have YOU messed with anything? Operator / mechanic error is the place to start.
  • dweben
    dweben Posts: 34
    Can be adjustment issues but also can be user error. Think you have two problems working together...

    For off the top of the big ring that'll be the top end limit on the front mech maybe. Does it skip off the cogs during changing from the middle to big ring, or while riding?

    The middle ring issue sounds like a gear selection error! If you go middle ring and the smallest cog on the rear the chain gets really slack. If you use this gear combo down a real bumpy trail chances are the mech is just flapping about and failing to keep the chain taut so it then flies off. I used to get this when getting a turn of speed in -- trick to get around that is on the downs to put it on the big ring up front and a bigger cog at the back (for the same gear ratio).

    Does mean a little cross gearing which if you did 99% of the time would wear your cogs out, but since it's 2 minutes down a section it's ok. :P

    Oh and how clean is the drivechain? Gunked up cogs don't work so well...
  • Coxy_UK
    Coxy_UK Posts: 297
    Limit screws are set correctly. The chain came off of the big ring when I wasn't changing gear at all. The first time it happened I was just gunning it down a typical fire road, no single track.

    I'm not sure whether I was changing gear when it came off the middle, however I never run middle front small rear. I'm not riding any different than I have on my previous bikes and have never experienced this problem.

    I may hit the trails again tomorrow so I shall clean and re-check everything all over again, and see how I get on.
    _______________________________________________________________________________________
    Tides of sin draw tighter and brighter, hours become heavier and weighted, and the shadows smile...dark and wild.
    <font color="blue">My Stumpy FSR Pic 1</font id="blue">
    <font color="red">My Stumpy FSR Pic 2</font id="red">
  • stubs
    stubs Posts: 5,001
    Is the spring on the rear derailler mech working properly by that I mean is it tensioning the chain. I have a Canyon Nerve XC 7.0 with SRAM X9 mech and the chain has bounced off a few times the spring in the mech feels really weedy. I am thinking to try out a different mech and or a chain guide.
    Fig rolls: proof that god loves cyclists and that she wants us to do another lap
  • Coxy_UK
    Coxy_UK Posts: 297
    I will have a look shortly, I may try adding tension to the spring.
    _______________________________________________________________________________________
    Tides of sin draw tighter and brighter, hours become heavier and weighted, and the shadows smile...dark and wild.
    <font color="blue">My Stumpy FSR Pic 1</font id="blue">
    <font color="red">My Stumpy FSR Pic 2</font id="red">
  • supersonic
    supersonic Posts: 82,708
    f you go middle ring and the smallest cog on the rear the chain gets really slack.

    It shouldn't, if the chain is the right length this is easily within the range of the derailer!

    Is the chain slipping past the mech cage?
    GT ZASKAR CARBON TEAM

    VOODOO CANZO

    Come and see me at https://www.facebook.com/biketyke/
  • Coxy_UK
    Coxy_UK Posts: 297
    No ride today, plan to be out tomorrow though weather permitting. I have cleaned and reset everything so gears appears to run beautifully... will just have to see what happens now.

    I will update as and when. Thanks.
    _______________________________________________________________________________________
    Tides of sin draw tighter and brighter, hours become heavier and weighted, and the shadows smile...dark and wild.
    <font color="blue">My Stumpy FSR Pic 1</font id="blue">
    <font color="red">My Stumpy FSR Pic 2</font id="red">
  • The Rookie
    The Rookie Posts: 27,812
    Its just not possible for the chain to come off the outside of the big ring with the front mech correctly set as the outer face of the cage should be less than the chain width from the ring, there simply shouldn't be enough space for it to fall through!

    Simon
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • stubs
    stubs Posts: 5,001
    The Beginner wrote:
    Its just not possible for the chain to come off the outside of the big ring with the front mech correctly set as the outer face of the cage should be less than the chain width from the ring, there simply shouldn't be enough space for it to fall through!

    Simon

    Unless it comes off the bottom why do you think chain guides work on the bottom run of the chainhttp://www.leisurelakesbikes.com/product/sunlinev1travelguideandbashguard.aspx?&id=15629
    Fig rolls: proof that god loves cyclists and that she wants us to do another lap
  • Coxy_UK
    Coxy_UK Posts: 297
    Well 15 miles of Swinley Forest later and the chain remained on, it shall be further tested tomorrow.
    _______________________________________________________________________________________
    Tides of sin draw tighter and brighter, hours become heavier and weighted, and the shadows smile...dark and wild.
    <font color="blue">My Stumpy FSR Pic 1</font id="blue">
    <font color="red">My Stumpy FSR Pic 2</font id="red">
  • The Rookie
    The Rookie Posts: 27,812
    stubs wrote:
    [
    Unless it comes off the bottom why do you think chain guides work on the bottom run of the chainhttp://www.leisurelakesbikes.com/product/sunlinev1travelguideandbashguard.aspx?&id=15629
    If its coming loose at the bottom, you'll never notice if your pedaling as it says in the first post he was.....

    Simon
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.

Categories