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I have a 2018 Trek Domane SL6 Disc that I've put ~2500km on. I purchased an R8000 dual Stages power meter (Left and Right units) and fitted it onto my bike (following all the steps outlined in the dealers manual, and on many youtube videos). I still have lots of life left in my chainrings, so I swapped put my old chainrings on my new right crankarm. Since then I have been getting a creak when I put a decent amount of power into the pedals. My troubleshooting steps have been as follows (with the creak remaining after each one but the last):

  • Checked the torque on the chainring bolts (installed to 14Nm)
  • Cleaned the hell out of the drivetrain re-lubed
  • Had the LBS replace the bottom bracket and re-install the cranks
  • Checked the torque on seatpost (and then cleaned the seatpost, re-applied friction paste, and re-torqued)
  • Checked the torque on the seatrails (and cleaned, applied a light grease between clamp and rails)
  • Removed the rear derailleur, regreased, and reinstalled.
  • Removed the pedals and tried riding with flat pedals.
  • Put the new chainrings on the power meter cranks (and then swapped back once it didn't help).
  • Put the old (non powermeter) left crankarm back on (with the power meter right crank arm).
  • Finally - I installed the old right crankarm with the old chainrings with the new left crankarm (with power) - and voila - no creak!

I then swapped the old chainrings back onto the new right crankarm and the creak returned.

Other than a manufacturing issue from Shimano, or a power meter installation issue from Stages - I can't imagine what the mechanism is that would cause a creak from a right crank arm (given the above steps).

Has anyone experienced an Ultegra R8000 right crankarm being the ultimate culprit of a creak?

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    Have you oiled your knees?
    – Daniel R Hicks
    Jun 17, 2019 at 1:45
  • Can you share how you installed the chainring bolts? I assume when you installed on the new drive side crank arm you you cleaned the bolts, cleaned the thread on the crank arm and applied new anti-seize or grease (or something else)?
    – Superman.Lopez
    Jun 17, 2019 at 1:58
  • Did you immediately remove the new chain rings? Or did you first try the crankset as completely new? If you did, was it originally quiet?
    – Superman.Lopez
    Jun 17, 2019 at 1:59
  • The chainring bolts were blue Loctited in by the LBS when they first installed it. So I used some isopropyl alcohol to try to degrade the loctite and then scraped the remaining out with a pick (from both the bolts and holes on the chainrings). I rinsed and air dried the chainrings before re-installing. After each time I reinstalled them I didn't put on anything (no loctite, no grease, no antisieze). I never did try the new crankset completely before disassembly.
    – Vitamin-T
    Jun 17, 2019 at 2:17
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    While testing for the creaks, I would use some grease on the chainring bolts in addition to making sure they are clean. Seeing you now also have an issue with the bolts itself (from your other question), I would not be surprised if it's the bolts that are creaking. It also sounds like you bought the new crankset from the LBS so I would definitely let them help you solve the issue. That's what the LBS is for! :)
    – Superman.Lopez
    Jun 17, 2019 at 4:46

3 Answers 3

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It seems that after all was said and done - putting the new crankset on another bike showed that the creak followed the crankset. Thus, the issue was a poorly bonded/other issue with the right crankarm or power meter.

My stock PF90BB was a bit loose as well, so the Token BB mentioned above was another benefit (and better design IMO).

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I believe it's the crank arm I've installed a new Token bbq and new pedals all installation instructions were followed and torque settings adhered to but it still creaks like grandma's rocking chair

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  • Hi, welcome to bicycles! The question is why the Ultegra 8000 crank arm seems to creak, and if anyone has firm evidence that it actually is the crank arm. It sounds like you have a similar problem, but it doesn't really answer the question.
    – DavidW
    Aug 13, 2020 at 2:48
  • Creaks can come from a variety of different places. Replacing the pedals and BB without solving the problem doesn't necessarily mean that it's the crank arm.
    – jimchristie ♦
    Feb 27 at 19:43
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Are you sure the creak is coming from the chainrings? If they fit properly and the bolts are tightened properly I can’t imagine them creaking.

I think it’s much more likely that the bottom bracket (apparently it’s a BB90 Press Fit?) or even the rear wheel or pedals/shoes are creaking.

Maybe the issue disappeared when you re-installed the old chainrings because by chance you got the bearing tension just right. Or maybe the new crankset has slightly different spindle dimensions.

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  • I'm pretty confident it's the cranks. I had the BB replaced and pressed in (PF90). The creak remains with flat pedals on the bike. I have another rear wheel I could try. It is possible I only got the bearing tension right on the one try, but I've reinstalled the new cranks almost 10 times throughout the troubleshooting process.
    – Vitamin-T
    Jun 17, 2019 at 13:55
  • @Vitamin-T Press-fit bottom brackets are prone to creaking. google.com/search?q=press+fit+bottom+bracket+creak If they don't creak, and you replace them, they can start to creak, even if the replacement is done completely correctly. Unfortunately, I don't think anyone makes an adapter that converts Trek's BB90 to a threaded bottom bracket, such as this Wheels Mfg PF30 adapter does for PF30 bikes.
    – Andrew Henle
    Jul 17, 2019 at 13:52
  • My LBS pointed me in a similar direction. For any other Trek owners reading this - a company called TOKEN makes one for Trek (tokenproducts.com/bottom-brackets/ninja/bb3724). I recieved one from factory two days ago and I'm going to install it tomorrow. Even if you don't have a local retailer that carries them the factory will arrange shipping to you if you email them (service at tokenproducts.com). Note, it needs a special install tool (BB3724R-2A). Fingers crossed it works! I'll update when I have a chance to take it for a spin with the new BB.
    – Vitamin-T
    Jul 18, 2019 at 14:20

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