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I am having problems understanding the source of a noise.

I would describe the noise as a intermittent crack or click that seems to come from where the seatpost encounters the frame. It stops when I stand on the pedals, and it seems the cracks arrive when I pedal some more vigorously, or when the wheels roll over some discontinuity of the road.

When I am off the saddle, the noise seems to be reproducible if I grab the saddle with one hand, the handlebar with the other hand, then I pull the saddle backwards.

Needless to say, this noise is unnerving, especially because I am not sure I am ruining the structural integrity of the bike.

Different things I tried, after reading here and elsewhere:

  • remove the seatpost, clean it and reinstall it after putting on a little bit of grease on the seatpost
  • remove the seatpost, clean it and the frame, put some grease inside the frame (just a bit), and reinstall the seatpost
  • remove the saddle, clean all parts that connect the saddle to the seatpost, reassemble
  • I bought a dynamometric wrench to be sure to torque the seatpost clamp according to specs; a couple of times before that, though, I screwed the clamp by hand: not sure I screwed it in too tight or not tight enough

Update

  • also tried greasing the saddle rails. Apparently no gain. Pretty sure at this point the noise does not come from around the saddle, but where the seatpost encounters the frame

Update 2023/05/06

  • tried swapping saddles, no gain. Greased again the frame, this time more generously, and it seems to perform better. Still some clicks after ~25 km, so I will try again with a more specific product (I've been using a generic grease)

All these measures seemed to help a little bit, but after some kilometers in the noise starts again. I didn't try yet to install a different saddle, but I doubt it would be a solution because as I said the noise seems to come from elsewhere.

In case they are relevant, here some details about the components:

  • Saddle, Brooks C17
  • Cannondale Topstone Alu frame
  • stock seatpost (I believe it's a Cannondale C3, 6061 Alloy)

Thank you in advance for any advice you can provide

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  • did you grease the saddle rails when you reinstalled the seat?
    – Swifty
    May 4 at 20:24
  • no, this is a thing I didn't try
    – larsen
    May 4 at 20:26
  • Could also check the bolts on the underside of the saddle. It looks like the rails are clamped with 3 bolts. My first instinct is the saddle. Do you have the oem saddle to swap out temporarily? I think my Topstone came with a Fabric or Fizik, so I'm assuming the Brooks was an upgrade.
    – shox
    May 4 at 20:35
  • 1
    @shox exactly. I still have the stock saddle to try a swap and see how different it will perform
    – larsen
    May 4 at 20:41
  • Updated the post with last thing tried
    – larsen
    May 5 at 16:38

1 Answer 1

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Swapping the seat temporarily is a way you can eliminate the possibility of it being the saddle.

If it is the saddle, sometimes it's necessary to lubricate the spots where the frame plugs into the upper. Ideally use a wicking lube like Triflow.

If it is coming from the post/frame interface, that's fairly unusual but does happen sometimes. Fiber grip type products are the best at eliminating noises in that area.

The most common cause of seatpost creaking is the saddle clamp is undertightened, which often relates to the bolt(s) being dirty and/or underlubricated.

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  • Thank you very much Nathan. I will give swapping the saddles a try. I would also like to acquire some "fiber grip type product" in preparation if that does not work: is there any specific product you may suggest? (I was looking for "assembly paste", but not sure how to incorporate "fiber grip type" in the search, and what to look for)
    – larsen
    May 5 at 19:46
  • @larsen There's a bunch of them that are similar but have different names. Carbon prep, fiber grip, liquid torque, etc. My favorite is the Tacx but it doesn't matter much. Honestly the difference between it and grease is pretty marginal for this application unless the post or frame are carbon, but it is superior at preventing movement.
    – Nathan Knutson
    May 5 at 21:56
  • Thank you. See above for the lastest update. I ruled out the saddle as the source of the noise, and I'm now trying to fix the post/frame interface. While inspecting the inside of the frame I noticed some scratches (visible, and I can feel them with a finger): I wonder if they're related to the problem, and how I could have produced them (I'm probably going to post another question about them). However, applying more grease seemed to solve the problem for a while, so I'm going to try with a more specific product like you suggested
    – larsen
    May 7 at 8:21

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