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I'm getting tired of debugging this noise, which seems to come from the back. I have sent it to the bike shop, for the second time, and they couldn't fix it. This sound came around 2 weeks after I bought it.It's not just sound; you can feel it in with every pedals revolution.

They guy said the bottom bracket was loose, and that he greased, lubed and tightened everything. For a while it was smooth, but 2 hours later it returned. It seems to come from the back (I always believed it was the pedals because you felt it there), but once I went down and got a friend to ride it it most definitely comes from the gears in the back. It can't be replicated but under tension and the most use the worse it get. I only use the bike to go to work, I honestly don't know how it got that bad.

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Update: they replaced the casette and I haven't heard the sound so far.

  • If your bike shop is unwilling or unable to fix this, your ultimate recourse may be to just return the bike to the shop and ask for a full refund. I'm not familiar with German consumer protection legislation but it would be very surprising if you're not entitled to a refund after buying defective goods. – David Richerby Jun 28 '17 at 7:47
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I guess you need to be methodical about discounting possibilities.

It sounds like bearings slipping around but a lot of rattles and clicks sound similar on a bike.

Have you got any spare pedals you can put on to see if it's them? Even just borrow a mate's set for 10 minutes.

Given that it always seems to be at the same parts of the pedal rotation I would discount the rear of the bike since the alignment of everything there varies with gearing.

Check for play down at the bottom bracket.

Make sure the axle doesn't shift side to side and that the crank arm on the non-drive side is sitting snugly enough to the bottom bracket.

Take the crank shaft out and check the bearings yourself. Are you short of some balls in there. Did the bike shop do as they said?

Get a new bottom bracket. They're often cheaper than you'd expect and fitting them isn't too bad. Even fitting press-fit bearings is easy with some threaded bar and some big washers. Of course your LBS can do this too.

I've had some creaks on my bike which happens to be carbon but because of this, the seat post noise seams to travel and sounds like a bottom bracket creak. It turned out to be fixable with a wipe down and some carbon paste in the end. Do something similar just in case. It certainly can't harm.

  • I think found it..., one of the cogs of the back derrailer seems completely screwed, how didn't I notice that? actually I'm surprised it can ride so smoothly at times. when I hit the cog with my finger to a side it makes a clicking sound (the cog itself) Or actually is the cog supposed to be able to move side to side and click? it starts rubbing inside the rear derailer and the rubbing itself puts it back in place, that might explain why it only happens when I apply pressure (pedal strokes). Or is that a normal behaviour a side to side movement in the rear derrailer cog? – Onza Jun 23 '17 at 19:30
  • The bike became unridable again, now it's rubbing everywhere; I literally took it from the bike shop 2 days ago. – Onza Jun 23 '17 at 19:31
  • Odd that the clicking stayed in sync with pedalling though since it will be spinning many times faster. Fixing rear derailleurs feels like a dark art to me although generally that means straightening them which seems to almost never work. Is your front chainring buckled and causing the lower chain to move side to side? That might explain the synchronicity. – Chris Jun 23 '17 at 19:57
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    @Onza: Yes, they are supposed to move side-to-side a considerable amount. – Michael Jun 23 '17 at 20:26
  • I understand what I find weird is why it would click, instead of moving side to side smoothly, maybe it's the pedal stroke that makes it move to the top (left side) and click, for instance in the video I'm driving in circles, siding my bike to the right side, it doesn't happen if I side it to the left; maybe the gravity throws the gear down (right side) and once I pedal stroke I get it back up (left side), causing the click sound to happen, I don't know that's my hypothesis, since the clicking noise is suspiciously similar. – Onza Jun 24 '17 at 12:49
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Looking at the video it seems the clicks are at the same point in the pedal rotation each time. Based on that I'd say it's your bottom bracket or your peddles not being tightly connected to the bottom bracket.

You can investigate this a little more by flipping over the bike and resting it on the seat and handlebars, then apply pressure to both pedals at the same time in both the rotating direction and perpendicular to it checking for any play. If there's any play try to determine where it is coming from.

It could be that a pedal is not tightly connected to the bottom bracket axle (especially if you only feel movement in one peddle) or it could be that the bottom bracket is loose or the axle broken in which case you ought to feel movement in both pedals.

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If you are climbing most likely the noise is a loose rear hub.

Very often the noise is emplified in the bottom bracket. Tightening less than a quarter turn of the pre-load will kill the noise.

My Mavic SLS wheel had this trouble. I spent 6 months to locate thr noise. The good thing is adjustments can be made with a Mavic tool without removing the wheel from tbe frame.

Hope this helps.

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