New chain slipping

I wonder whether anyone can help me please.

I have a carerra subway 2 and have replaced the chain today. I was careful to measure the number links on the original chain and reduced the length of the new chain so it was same number of links. It ended up about an inch shorter than the original chain so I put this down to how much the original one must have stretched.

Having fitted new chain and indexed front and rear derailleurs again all seemed fine when I turned the pedals when it was up on a stand. However when I took it out for a ride every gear slips badly when the front chain ring is on the smaller cog. Doesn't do it at all on larger chain ring, just the smaller one.

It wasn't doing it before so should I try adding a couple of spare links into the new chain to increase the length, or does this mean that I'll need to replace the rear cassette now as I've read that they wear at the same rate as the chains?

TIA.

Comments

  • In addition to replacing the rear cassette, should I also replace the two jockey wheels whilst I’m at it?
  • veronese68
    veronese68 Posts: 27,189
    No need to change jockey wheels unless they've lost all the teeth which I doubt.
    You can get away without changing the cassette if you change the chain early enough, but not this time by the sound of it.
  • antonyfromoz
    antonyfromoz Posts: 482
    edited April 2020
    totally agree with Veronese's comment above - the only time this happened to me was due to several of the cogs on the cassette having had their teeth worn down but these tend to take the brunt of a worn out chain rather than the jockey wheels (still probably worth checking though). Also worthwhile to invest in a chain measuring tool to avoid having the expense of changing the cassette so often.
  • cruff
    cruff Posts: 1,518
    Easiest way to check this is to see if it only happens in the middle of the block, since - if you're like 90% of people - you'll spend most of your time on cogs 5, 6, 7 & 8. If it only slips on those (or mainly on those) then yeah, you've worn a 'memory' into the cassette. I generally change my chains before the gauge indicates stretch of 1.0 (not quite when it drops into the chain on 0.5, but a few hundred miles after). That gets me three chains worth of use out of an Ultegra cassette
    Fat chopper. Some racing. Some testing. Some crashing.
    Specialising in Git Daaahns and Cafs. Norvern Munkey/Transplanted Laaandoner.
  • Thanks for the comments everyone and that's very helpful to know that I won't have to replace the jockey wheels. The chain seems to be slipping on every cog, but only does it when I'm pedalling the bike and not when it's up on the service stand.

    As it's only slipping when the chain is on the smallest chain ring (there are two rings on the front) then would this possibility mean that it's one of chain ring that's worn and needs replacing?
  • wongataa
    wongataa Posts: 1,001
    The chain isn't slipping on the stand as there is no load on the back wheel. Try (wearing suitable gloves) to resist the turning of the back wheel while turning the cranks and see if you can induce slipping to see where it is more clearly.

    It may only slip on the small chain ring as it could be that the different chain line on the big one puts enough tension in the system to stop the slipping.

    I would still just change the cassette. They are pretty cheap and it would most likely fix the issue. If you are still having slipping after the cassette change then the chain rings are too worn and would need to be replaced anyway as well.
  • Darius_Jedburgh
    Darius_Jedburgh Posts: 675
    edited April 2020
    From what I can remember of your earlier photos I would replace everything. Chain, cassette and front rings. That way you have a brand new drive train which will/should be trouble free for some time to come. Eliminate all the possibilities for problems; in the long run it makes sense.
  • Thanks again for the tips.

    I guess it's a process of elimination so I'll replace the rear cassette first and see of this solves the problem. If it doesn't then I'll look at replacing the two rings on the front chain set. From memory I think these can be replaced individually without having to replace the whole crank?

    I'll also try turning the pedals whilst it's up on a stand and hold onto the tyre to see if it's slipping under load.




  • I've posted a few photos of the chain rings and rear cassette
  • Charlie_Croker
    Charlie_Croker Posts: 1,687
    Yep there knackered, as FrankYates said replace the lot for trouble free cycling
  • Thanks Charlie, I've already ordered the rear cassette so may as well bite the bullet and replace the front chain rings as well whilst I'm at it
  • That big ring is shot.
  • I might as well do both front and rear then. It's my spare bike and probably only worth about 50 quid, but I've had it so long, I've got kind of attached to it!

    If I spend a bit on it now then it should last me a few more years as I only use it occasionally anyway.
  • adamzworld
    adamzworld Posts: 29
    As
    an update to my original post, I replaced the rear cassette today, but unfortunately the chain is still slipping. I've ordered replacement chain rings as well so will fit them as soon as I have them and hope this sorts the problem. If it doesn't then I'm not sure what else I can do except for maybe trying to remove a link from the chain to see if this helps.

    I've attached photos of the old chain rings and the small one doesn't look too bad to me, but I don't really know what a badly worn one would look like.





  • daxplusplus
    daxplusplus Posts: 631
    Ouch that inner (small) chain ring looks seriously sharp\warn out. Compare your teeth to a new one .. a lot less pointy on the new one

    Sometimes you're the hammer, sometimes you're the nail

    strava profile
  • Charlie_Croker
    Charlie_Croker Posts: 1,687
    If you also buy yourself a cheap (when compared to a new drivetrain) chain wear indicator to check the chain wear from time to time (It’s almost impossible to judge chain wear without one), you’ll avoid wearing everything out. A worn chain wears the teeth away like this. Even if it didn't slip it would wear a new chain out quicker than a good chainring.




    Clean, dry and lubricate your new drivetrain routinely and you’ll get many more times the life of a dirty unloved one.
  • adamzworld
    adamzworld Posts: 29

    Ouch that inner (small) chain ring looks seriously sharp\warn out. Compare your teeth to a new one .. a lot less pointy on the new one

    Thanks for the feedback and I wondered before whether a worn chain ring would end up with more rounded teeth, but it sounds like sharpened teeth are also a sign
  • adamzworld
    adamzworld Posts: 29

    If you also buy yourself a cheap (when compared to a new drivetrain) chain wear indicator to check the chain wear from time to time (It’s almost impossible to judge chain wear without one), you’ll avoid wearing everything out. A worn chain wears the teeth away like this. Even if it didn't slip it would wear a new chain out quicker than a good chainring.




    Clean, dry and lubricate your new drivetrain routinely and you’ll get many more times the life of a dirty unloved one.
    Thanks for the feedback Charlie. Are the chain wear indicators you refer to the ones that are used to measure the length of chain and show whether the chain has stretched?
  • Charlie_Croker
    Charlie_Croker Posts: 1,687

    If you also buy yourself a cheap (when compared to a new drivetrain) chain wear indicator to check the chain wear from time to time (It’s almost impossible to judge chain wear without one), you’ll avoid wearing everything out. A worn chain wears the teeth away like this. Even if it didn't slip it would wear a new chain out quicker than a good chainring.




    Clean, dry and lubricate your new drivetrain routinely and you’ll get many more times the life of a dirty unloved one.
    Thanks for the feedback Charlie. Are the chain wear indicators you refer to the ones that are used to measure the length of chain and show whether the chain has stretched?
    Yes they are the ones, they say 0.5 and 1.0 or 0.75 and 1.0 on most, that's a percentage of wear, when you reach the first marker it's time to order your new chain and save your cassette and chainrings.



    The point falls into the gap when the chain is worn
    You can of course measure a chain with a steel rule. 12 pairs of links will measure 12" on a new chain, but the tools are easier/simpler
  • adamzworld
    adamzworld Posts: 29
    Thanks Charlie, I've seen these online and they're not that expensive, so probably a good addition to my toolbox