Chain keeps falling off when climbing?

davehmercer Posts: 82
edited December 2012 in Road general
Just wandering if anyone can shed some light on this rather irritating and frequent occurrence for me?

A few weeks ago I changed my groupset from the Shimano Sora 9 speed that my bike came with, to Campag Centaur 10 speed, now pretty much every time I climb a hill and I am in the lowest gear (Top of cassette 26 tooth, lower ring compact chainset) my chain comes off?

I have set up the gears and they all seem to shift nicely and I don't get any other issues. The only thing I can think is that I havent changed the chainset which is the original FSA one that came on my bike (2010 Bianchi Via Nirone 7)? I have a new cassette (13-26), front and rear Derailleur's, shifters, cables and chain. Could this be the issue?

Any advice would be much appreciated.

Thanks in advance.



  • nicklouse
    nicklouse Posts: 50,675
    so how is it comming off?

    of the rings or off the cassette?
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
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  • Sorry should have said, its coming off of the chainset ring.

  • Monty Dog
    Monty Dog Posts: 20,614
    Check the alignment and set-up of your front mech - the outer cage plate could be too far inboard and pushing the chain off. It may be compounded by a flexing crank/bb i.e. as you push down, it flexes outboard. The inner cage plate only just needs to clear the inside of the chain.
    Make mine an Italian, with Campagnolo on the side..
  • lc1981
    lc1981 Posts: 820
    Does it come off as you're shifting gear, or some time after you've shifted into the lowest gear?
  • It shouldn't come off but if you can't sort it think about a chain catcher.
  • Gizmodo
    Gizmodo Posts: 1,928
    If it is falling off the small chainring when you shift down from the large ring whilst under load, do 2 things. Adjust the low stop screw slightly so the front mech doesn't go quite so far in (it may be just a fraction) and don't drop down under load, just back of the power for half a second whilst you change gear. That's what worked for me.
  • Thanks for the replys chaps,

    It doesn't happen when changing down it only seems to happen when peddling up hill without too much pressure on the pedals?

    Ill check everything that has been recommended and try again.
  • brettjmcc
    brettjmcc Posts: 1,361
    Double check the chain. I had something similar last year and it turned out that one of the links had slightly bent/mishaped. New chain and it was fixed for me.
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  • brettjmcc wrote:
    Double check the chain. I had something similar last year and it turned out that one of the links had slightly bent/mishaped. New chain and it was fixed for me.

    Ahh, that sounds like it could be the issue as I did make a bit of a hash up of the fitting of the new chain and managed cock up one of the links! Ill pop out and get another chain! :D

  • Did you sort the problem as i have the same problem
  • daniel_b
    daniel_b Posts: 11,652
    edited February 2021

    For me, it was worn chainrings, experienced only when really putting the power down.
    Dependent on the chainset, and ring, it can be a really cheap repair.
    Felt F70 05 (Turbo)
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  • pilot_pete
    pilot_pete Posts: 2,120

    Did you sort the problem as i have the same problem

    1. Check the front derailleur setup. Especially the end stop screws to ensure the chain cannot jump off inside the rings when shifting. It’s best to start from first principles just in case it wasn’t set up properly in the first place - if it’s Shimano, search for the Dealer Manual for your groupset and follow the instructions for setting it up correctly. This costs nothing assuming the cable inner and outer are in good condition and the derailleur itself is working properly. Ensure the inner cables run freely and are not corroded or kinked - remove the cable from the derailleur clamp and hold it whilst operating the shifter through its range of movement. There should be little resistance.

    2. Check your chain and chainrings for wear. A simple drop in chain checker tool costs peanuts. If the chain is overly worn, you will need a new chain. If it’s been worn for a long time it may have worn the chainring(s) and rear cassette teeth too - this can mean a new chain will jump and not run smoothly due to hooked teeth. If that’s the case then new chainrings (or even a new chainset which sometimes works out cheaper) may be required, and/or a new cassette on the rear. The teeth should have ‘U’ shaped gaps between them. If the ‘U’ is not symmetrical and elongated on the front edge, that is wear.

    Check your chainrings for bent or damaged teeth - they are all different, some taller, some shorter, some with scalloping on their edge etc, which is normal and aids with shifting the chain. What you are looking for is any damaged teeth, especially a tooth that is bent towards or away from you as you look at the chainring side on. (Which means bent left or right of the centreline of rotation when looked at end on). This can unship a perfectly good chain.

    3. Check your chain ring bolts are tight. I’ve seen sloppy front shifting caused by play in the chainrings due to the bolts working loose. It’s a good idea to remove, clean the threads and apply with loctite (blue) or coppaslip grease to prevent them seizing.

    4. If wear isn’t excessive on the rings/ cassette and the chain isn’t worn, check the chain for any tight or damaged links. If it has a split link I would recommend removing the chain after a thorough cleaning and drying, then laying it on a table and working your way along each link checking for any damage/ kinks in the side plates and moving each link between your fingers to ensure they move freely. If you find a tight one, that is not damaged, just flex the chain forwards and backwards side on (if that makes sense) around the stiff link. This can free it off.

    5. Check the bottom bracket bearings to ensure there is no play, and the cranks to ensure they are tightened to spec. Check for end play (side to side) and if there are spacers ensure they are fitted on the correct side/ in the correct order) - some chain sets have plastic or metal spacers and the installation instructions will tell you which side and how many should be put on the crank spindle before installation to ensure the correct chain line.

    6. When refitting the chain, ensure you put it on the correct way around if it is directional. Some are, some aren’t. Again, the dealer manual will tell you if Shimano and generally they tend to have logos on the outside, some have little arrows etc.

    If that lot doesn’t sort it I would then try a new chain as a last resort. You should find something amongst that lot will sort the problem.