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About a year ago I've got this Stevens Supreme fitted with Shimano Tiagra BB-RS500 bottom bracket.

In less than 2 months it started clicking and screeching loudly which only had gotten worse over time. Eventually I decided to get a replacement and to try something else, and installed Shimano Ultegra SM-BBR60 BB but unfortunately it had shown exactly the same problem, again in less than 2 months. I can get a replacement once more but I wonder if there is something wrong with the bike frame, or I have to do some maintenance to keep the bearings in good shape. So I see these options:

  1. I am just unlucky and just have to replace it once more and hope it will be OK the next time.
  2. There is something wrong with the bike's frame itself. I noticed that if I press pedals very hard it noticeably bends. So I may imagine that the bottom bracket does not like side forces. I am not sure what to do if this is the actual problem.
  3. The noise comes from somewhere else. But it clearly synchronized with crank rotation, also after I have installed a replacement it did run smoothly for some weeks.
  4. The bearings require some dedicated maintenance. But I could not find any instructions in this regard, and there is "do not disassemble" on the bearing's rim. So the best I could imagine is to use some liquid oil that can get in without taking the cartridge apart. I tried that but it helps only for 15 minutes of riding and only temporarily.
  5. I read somewhere that these models of bottom brackets use small-ball bearings, maybe there are some compatible bearings that I could try and that are more reliable?
  6. Maybe there is a way to restore the bearings?
  7. Something else?

Did you have similar problem?

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    Smells like potential mis-alignment in the frame between the two sides - I suggest contacting Stevens immediately, to start a paper trail. Do it today !
    – Criggie
    Aug 27, 2023 at 23:08
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    noticed that if I press pedals very hard it noticeably bends. How are you pressing the pedals? How is the bike bending when you do that? Most bikes will flex some around the bottom bracket under hard pedaling - it's really hard to make a frame that only weighs a few kilos completely rigid under hard pedaling loads. And FWIW, one potential quick and easy possible fix: teflon plumber's tape. If the bottom bracket is rocking within its threads some, the teflon plumber's tape might fix that. Aug 27, 2023 at 23:18
  • Hard pressing on a pedal down makes the frame around bottom bracket to bend sideways (about 2-3 degrees) so the crank axle becomes not perfectly horizontal. Maybe this indeed could be normal since the frame is very lightweight. The bottom bracket and the axle in it both sit perfectly tight at all times so the fitting does not seem to be a problem. Aug 28, 2023 at 13:10

1 Answer 1

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I agree with @Criggie regarding the comment that there is a high suspicion of misalignment of the bottom bracket cups (they are not perfectly parallel) when they are installed. This infers a misalignment in the frame or some flaw in the bore of the BB shell. If the cups are not parallel, there is uneven forces acting on the bearings causing premature wear and noise. The evidence for this is the very early noises produced by 2 different bottom brackets--ones that are typically high quality, long lasting models. If you uninstall the right crank to expose the spindle, you will notice the rings around the spindle where the bearings articulate. Look for inconsistencies in these tracts. This would also be evidence of a misalignment.

These Shimano Hollowtech2 bottom brackets are not serviceable. They can be cleaned externally and fresh grease applied on the inner aspects, the rings that touch the spindle as well as the spindle itself. Access to the bearings is not possible. Not easily and without a high probability of damage to the sealing system.

A well-equipped bike shop will have tools that check the parallelism of the bike's BB shell. They could "face" the ends of the shell--remove material--to make the ends parallel to each other and that will allow the cups to be parallel when installed. However if the bores of each side have center points that are not on the same line, that would be a problem that can't be solved (AFAIK).

Check, too, with Stevens and any warranty they may offer. The shop where you got the bike should be willing to help in that regard, including the testing of the shell for parallelism and/or bore misalignment.

Here is a link to the English PDF of the Stevens Bicycle User Manual. On page 93 you'll find the warranty details. The warranty is 2 years from date of purchase, so you should have ample time to work it out.

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  • I took the crank off, and could not see any obvious misalignment or any visible wearing on the parts. Rotating the bearings manually, I am inclined to think that either the bearing balls are defective or there is some sand inside. Will contact Stevens service anyway. Aug 28, 2023 at 15:37
  • @PetrGladkikh The misalignment will not be visible. A tapping set or similar would be necessary (BTS-1, Unior 1698,...). Aug 28, 2023 at 19:08
  • Have taken to the dealer for repairs, it took only 2 weeks, and I paid for it. Aaand... the same problem after 300 meters out of the gate. Oct 12, 2023 at 20:48

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