When it sounds like your chain is slipping, but it isn't?

cgfw201
cgfw201 Posts: 680
edited May 2019 in Workshop
I’ve had an issue on my Canyon for about 6 months. Basically, about once or twice an hour, on any ride in any conditions, I’ll have a split second where my drivechain makes a noise as if the chain has missed a tooth and slipped. But it isn’t. I’ve replaced the big ring, chain and cassette and have the same issue across two different wheelsets. I thought it could be a freehub or pawl problem, but they are also fine.

It tends to happen pulling away from stationary on maybe the first, second or third pedal stroke, and will be a quick click/clonk and then everything carries on as normal. The derailleur alignment is spot on and shifting is perfect. I’ve also replaced all the cables whilst having this issue.

I took to a LBS around 4 months ago and mentioned this issue and they coulnd’t find an obvious cause, and I’ve just lived with it since. It’s not a major issue, but I do have a nagging doubt when out the saddle sprinting that something is about to go wrong and stick me on the deck.

Anyone able to make sense of the above and have a theory on what the issue could be?

Comments

  • webboo
    webboo Posts: 6,087
    Are you sure it’s not your free hub. I get a clunk with one of mine usually when freewheeling down a dip then getting out of the saddle as I hit the incline. It has a split second delay before engaging.
  • cgfw201
    cgfw201 Posts: 680
    Webboo wrote:
    Are you sure it’s not your free hub. I get a clunk with one of mine usually when freewheeling down a dip then getting out of the saddle as I hit the incline. It has a split second delay before engaging.

    That was what I initially thought it was, and thought it would be fixed by switching to my nice summer wheels, but situation remained the same on both. Also gave my freehub a full service a few weeks ago as it was getting sticky on descents.
  • step83
    step83 Posts: 4,170
    How are the jockeys an spring on the mech? You have pretty much changed an checked everything else, could be something as simple as a stiff spring or worn/damaged jockey wheel.
  • keef66
    keef66 Posts: 13,123
    edited May 2019
    Bizarre that you've changed just about every part of the drivetrain including wheelsets but the issue persists. As above, is the RD all hunky dory? Cage / jockey wheels / pivots / springs / firmly attached to the hanger / hanger not bent / hanger firmly attached to frame?

    Does it happen spontaneously, or is it just after a gear change so the cables / shifters might be implicated?

    Is it possible the frame's compromised somewhere??
  • cgfw201
    cgfw201 Posts: 680
    Step83 wrote:
    How are the jockeys an spring on the mech? You have pretty much changed an checked everything else, could be something as simple as a stiff spring or worn/damaged jockey wheel.

    Replaced the whole RD in July last year after a big crash, spring is fine, jockey wheels I'll check. They get removed and cleaned every couple of months but could be an issue.
  • keef66
    keef66 Posts: 13,123
    cgfw201 wrote:
    Step83 wrote:
    How are the jockeys an spring on the mech? You have pretty much changed an checked everything else, could be something as simple as a stiff spring or worn/damaged jockey wheel.

    Replaced the whole RD in July last year after a big crash, spring is fine, jockey wheels I'll check. They get removed and cleaned every couple of months but could be an issue.

    Do you have another RD you could briefly swap in? Was your big crash big enough to have damaged the frame or the right shifter? Have you peeled back the hood to check the shifter body's intact (I'm guessing yes if you've replaced cables)
  • N0bodyOfTheGoat
    N0bodyOfTheGoat Posts: 6,034
    Did you change big ring, chain and cassette at the same time, or could a heavily worn original have rapidly messed up the new drivechain?

    Could a directional chain on the wrong way around cause this?
    ================
    2020 Voodoo Marasa
    2017 Cube Attain GTC Pro Disc 2016
    2016 Voodoo Wazoo
  • bondurant
    bondurant Posts: 858
    This noise or feeling could also be the chain momentarily riding on a tooth (to the side) then falling into place. Happens on my bikes once in a while. If this is the case, don't worry.
  • jermas
    jermas Posts: 484
    I know the freehub/pawls have already been discussed, but lubing them with grease or sticky oil can (on certain hubs with weak pawl springs) allow the pawls to momentarily remain open -especially after freewheeling or starting from junctions.
    Thinner non sticky oil might cure it.
  • cossyrush
    cossyrush Posts: 43
    Interesting thread, I get this on my winter bike, a Trek Domane, with 105 group set.
    I’m convinced it’s coming from the chainset.
    I’ve had the rings off, cleaned, refitted, there’s nothing obvious, and everything looks ok.
    I just put up with it now, but I bet if I change the crankset it will go away.
  • Alejandrosdog
    Alejandrosdog Posts: 1,975
    its haunted
  • If this only started happening after the crash and is when your putting power through the drive train ie starting from stationary then I would consider the frame may have damage and is flexing when you put power down.

    You've replaced just about everything else!