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Help please – Chain slipping badly when applying pressure

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  • March 9, 2015 at 8:39 pm #23453
    Haggisbasher

    Hello all

    Looking for some pointers/help.

    I recently measured chain and was shocked to see that after 8 months and 3000km the chain has stretched to over 1%. I replaced the chain, and when out riding I started to get terrible chain slip (not slipping up and down the gears) but riding over, i think the cassette. Prior to the chainswap I had no problems, hving been out in strong winds and pedaling hard.

    I thought the cassette might also be worn or the pawls so checked with three other wheels and cassettes, still same problem. Thought it might be a duff chain, so changed that, no difference. Thought on the off chance that all cassettes were worn, so bought new one (slowly, buying new groupset part by part here). I had a look at the front small chainring and it looks slightly worn but not bad. The slip only occurs when I am in the small chainring at the front and the 4-5 smallest gears at the back (yeah i know I shouldnt be crosschaining)

    Could worn jockey wheels cause the chainslip? (these are even newer about 7 months and are Hope jockey wheels) or is it more likely the front chainring. Options left are new derailleur or chainring.

    An thoughts greatly appreciated.

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Viewing 15 replies - 16 through 30 (of 54 total)
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  • March 12, 2015 at 8:33 pm #835831
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    Haggisbasher

    Thanks for that, I do value
    Thanks for that, I do value everyone’s comments, even the smart arse one about taking up gardening. I can fix most things but this got me stumped, hence asking others for similar experiences.

    While most comments are well meaning and sharing their experiences, a lot are not taking on board the initial posting. I have a day off tomorrow so I will strip it down, recheck chain length and derailliuer.

    Failing that LBS will help sort it out.

    March 12, 2015 at 7:07 pm #835829
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    crazy-legs

    First thing is to STOP.
    Stop
    First thing is to STOP.
    Stop adjusting this, buying that, fettling with the other. It’s got to the point where any of the above answers could be right or wrong and you have no way of telling which is which or the expertise of the people offering their opinions based on a few photos and a vague description.

    You’re just throwing money at the problem and hoping it’ll go away.

    Take the bike to a reputable shop. The problem could be anything from half a turn on the barrel adjuster to an entire new drivetrain and the only way to find out if you’re not sure what you’re doing is to hand it over to the people who do know.
    If you don’t trust the opinion of the first shop, take it to a second, there’s no harm in asking around – go in and say “could you have a look at this issue and tell me what you think is causing it?” rather than simply “fix this”. That way you’re under no obligation to get any work done, you can evaluate the info the shop has given you and go from there.

    Posting on here is just going to lead to a host of “experts” confusing matters still further and you buying various random bits of drivetrain piece by piece (any or all of which may have varying degrees of compatibility issues with each other).

    March 12, 2015 at 7:03 pm #835827
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    crikey

    Chains snap because they have
    Chains snap because they have been installed incorrectly.
    They don’t snap because they get worn, and certainly not because they’ve done 2’000 miles!

    Chains, chainrings and cassettes wear together. Wear them out; you’ll be surprised how many miles you get out of them.

    March 12, 2015 at 6:50 pm #835825
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    Pub bike

    crikey wrote:Run chains and

    crikey wrote:
    Run chains and cassettes together, throw them both away when they eventually die; you’ll get a far easier life, far better shifting and save money.

    Sheldon Brown in the section on [url=http://sheldonbrown.com/chains.html/]Measuring Chain Wear[/url] does not agree.

    Before I started measuring I wore a chain and cassette out together as you describe, because I didn’t have a plan. I got 2,000 miles out of the chain and then it snapped whilst setting off from some traffic lights. I repaired it and rode off and of course it snapped again. Luckily I was not hurt either time although I could have been.

    Nowadays that bike is reserved for once-a-year fully loaded tours in the high mountains, and I change the chain on it before every tour. The cassette is from 2008. still no sign of slipping, and not had any kind of chain incident on tour.

    Of course your mileage may vary…literally, but in any case how do you know when to change the chain if you don’t want it to snap on a ride?

    March 12, 2015 at 5:37 pm #835823
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    crikey

    All these problems stemmed
    All these problems stemmed from measuring the chain and following received wisdom regarding what to do.

    Chain checking is a modern phenomenon; no one did until 3 or 4 years ago.

    Run chains and cassettes together, throw them both away when they eventually die; you’ll get a far easier life, far better shifting and save money.

    March 12, 2015 at 5:32 pm #835821
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    shearer27

    I see you have aftermarket
    I see you have aftermarket jockey wheels (red). Could these be a contributing factor I wonder? Is it a Shimano/Sram chain? Would be interested to see the position of the derailleur with the chain on the small chainring at the front and smallest cog on the cassette.

    March 12, 2015 at 5:08 pm #835819
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    Pub bike

    It is worth getting a chain
    It is worth getting a chain measuring tool and using it every time you clean your chain, and not letting the chain elongate beyond 0.75. After 0.75 everything starts to get expensive as the chain very quickly eats its way through your cassette sprockets and then eventually the chainrings.

    If your chain has reached 1.0 on a chain measuring tool (i.e. worn out), your cassette is probably worn out also.

    A worn-out chain will very quickly wear out a new cassette. Your new cassette might have fallen victim to this chain already?

    I’ve managed to wear out a Shimano Deore alloy 36T middle chainring such that the chain slipped. Replaced it with a steel one and don’t let my chain get that worn anymore.

    My experience is that by changing chains regularly I can get my cassettes to last around 3x longer than my chains.

    Some people recommend having 3 chains and rotating between them on the same cassette so that everything wears at approximately the same rate.

    March 12, 2015 at 4:49 pm #835817
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    Tompotblenny

    Time to treat yourself to a
    Time to treat yourself to a new bike? 😉 But seriously, lots of good ideas here and do let us all know when you figure out what the problem is. Best of luck.

    March 12, 2015 at 1:04 am #835815
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    Bedfordshire Clanger

    Does the derailleur move
    Does the derailleur move freely fore and aft? If it is at all sticky that might be the cause of your problem. As previous posters state, if the cassette isn’t worn then the problem could be chain tension. Does the chain sag when you use the gear combinations that slip? Is it difficult to back pedal using the slipping combinations? Either of these scenarios indicate a chain tension problem that could be related to chain length or a derailleur that sticks in certain places. If this is the case it would explain why you can pedal without trouble on the big ring but the small ring to small sprocket combinations slip because there is less tension in the chain. If your rear mech is sticky give it a good clean and lube all moving parts.

    March 11, 2015 at 11:08 pm #835813
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    Haggisbasher

    side pic as requested, Big
    side pic as requested, Big chainring at front, small ring at back.

    The scrape on the derailleur is from a fall many years ago.

    March 11, 2015 at 6:45 pm #835811
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    Colin Peyresourde

    Could it be the chain length?
    Could it be the chain length? Silly question in a way. But I bought a chain from Cycle Surgery and was told that it was the right length and I just needed to attach it with a power link. I thought that was unusual. Rode the bike home and the chain slipped all the way – initially thought it was a worn cassette, but after a bit more inspection I realised that the chain was entirely too long.

    I was furious at the CS, but also myself at taking the utter rot that they told me as red. I did have an accident, and consider myself fortunate that it didn’t happen on a road with cars.

    March 11, 2015 at 6:08 pm #835809
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    Haggisbasher

    Thanks all for the comments,
    Thanks all for the comments, the chain has the same links as the previous one and the one before that. Going from the comments, it would appear the derailleur is the most likely problem, or the hanger.

    I will seek professional help from brother in law at weekend or LBS after that. Just need to find one that has a good mechanic.

    I will take a side picture, and when I find the problem, I will be sure to let you all know.

    Thanks everyone for being helpful.

    March 11, 2015 at 12:59 pm #835807
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    Anonymous

    Can you provide a photo that
    Can you provide a photo that is taken side on to show the whole drive-train?

    From that picture it is really hard to tell, but the hanger does look off, as the top jockey wheel looks to be at an angle to the chain as it runs onto the cassette. Also it may be the angle of the photo, but the main mech body appears to be pulled right back, and with that amount of slack in the chain a conventional mech wouldn’t sit like that. Is it stuck in the rearward position?
    My guess is you pulled it back to get the wheel out, and it has got stuck in that position.

    March 11, 2015 at 11:49 am #835805
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    RR

    It’s hard to tell much from a
    It’s hard to tell much from a single picture. Though I also think the derailleur pulleys don’t look adjusted inline with the cogs – possibly a bit too far to the right. Also something maybe be funny about the barrel adjuster; I can’t see the lip of the inner metal bit, is it just fully wound in? And the ferule on the end of the cable doesn’t look like it is sitting straight in the adjuster. However it’s probably all just the light!

    Was the new chain shortened to the same length as the old one? If it was and there were no problems before, I’d then assume the problem is something else. If the chain doesn’t sag or rub back against itself with the small chainring and small cog it’s probably not the issue, though it may be worth sizing the length properly.

    I would consider finding a bike shop with a good workshop if you are stumped. Paying someone with the experience and who can see the bike first hand may work out cheaper than throwing new parts at it when the old parts might actually be fine.

    March 11, 2015 at 10:44 am #835803
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    DaveE128

    When I replaced the chain and
    When I replaced the chain and cassette on a mountain bike a while back, the wear on the middle ring was enough to cause slipping when I put the power down. The chain slipped on the chainring but it was hard to tell where the slip was happening. Replacing the chainring eliminated it. Hope it will for you too.

    However, as others have said, the angle of the rear mech looks weird – the body of the mech seems to be rotated back and up from its normal position. Can you take a photo from the side of the bike in the same gear?

    The chain routing through the rear mech also looks funny but it may just be the perspective and the odd angle of the cage. Again, photo from the side and we’ll be able to tell if all is well.

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