Brand New Ultegra 8050 Drivetrain Pulsing and Noisy [Video of Problem]
 

*Video links at the bottom to hear the noise*

I recently built up my first bike from a bare frame (2020 - Trek Speed Concept). The drivetrain is Ultegra Di2 8050, with the exception of the chain which is Dura-Ace. The frame and all components were bought/installed new.

The drivetrain just seems noisier then it should be (the overall noise and kind of a clicking, and at times there is a pulsing or vibrating that I can feel in the drivetrain/pedals); this is in comparison to an older Cervelo R3 I have which has Ultegra 8000 mechanical drive train. The bike shifts crisply, but I’d like to identify and eliminate the noise. I’ve ridden the bike approximately 500 miles, the bike has never been dropped or damaged.

I initially thought the noise could have something to do with my Zipp 404’s, which seemed to make more noise then a pair of Ican wheels (see videos below), but when I put the bike on a trainer, I get much of the same noise and feeling. With the Zipp’s on, the noise and pulsing seems most prevalent in the smallest cog and large chain ring. The noise is less pronounced in the same gear combination with the Ican wheels on. On the trainer, the noise is most pronounced when the bike is in the largest chain ring and 2nd to the largest cog (so almost cross chained). On the trainer, when I shift to the small chain ring and middle cog, the bike is at the noise level I would expect (quiet) and there is no pulsing feeling.

I’m no bike mechanic (I've been learning as I go), but I’vetried a few things to diagnose the issue, and now I’m at a loss for what to try next:

-Re-indexed

-Lubed and cleaned the chain (a couple times)

-Double checked the chain size (it was accurately sized according to Park Tools Youtube video on how to size a chain). I also tried a chain that was two links shorter. Same issue.

-I Have tried 3 different cassettes (on two different sets of wheels and a trainer).

-Checked the torque on the cassettes.

-Removed the chain to check for any sounds or play in the bottom bracket; felt smooth and no play

-Removed the chain and checked the jocky wheels, spun freely

-Initially thinking the Zipp wheel was the issue, I pulled it apart, bearings seemed good, wheel is true, and dishing is not dead center, but within 1mm, which I understand to be within tolerance.


Video of bike on trainer (at about 12 seconds the sound is most pronounced and at 23 second the shifting brings the sound to what I consider to be a normal level):
Video of sound with Zipp wheel on:
Video of sound with Ican wheel on (same gears as Zipp):

Any thoughts or suggestions are appreciated!

When you say you “indexed”, you checked / trimmed with either shifter adjustment or etube software?

if you did do this without the software by going into the adjustment mode and jogging the RD with the shifter buttons, I’d try again……easy to lose your reference point….I prefer using the software…

Another possibility, is a very slightly bent Derailleur hangar….have alignment checked …..

How old = worn are the cassettes?

Yes, I checked and trimmed with the shifter adjustments. It shifts crisply into all gears, and doesn't make the "crackling" sound I'm accustom to when my Cervelo is not indexed properly, so I'm not thinking it's the indexing, but I did to it with the shifter buttons and not the software. I'm not familiar with doing it via the etube software, so I'll find a video on how to do that with the software and give that a try tomorrow.

I checked it tonight with a Park Derailleur hanger tool (probably should have done that earlier to rule it out 100%, but visually it looked good and the crips shifting made me think it was ok). The hangar was aligned properly (less than .5mm at any of the 4 points checked), so that doesn't seem to be it.

The cassette on the Zipp wheels was new with this build, so it has less than 200 miles on it (the other 300 miles on the bike have been on the direct drive trainer). The cassette on the trainer is around 1500 miles and the one on the Icann wheel is around 3500.

Thanks for the ideas/response, I'll check the etube indexing and report back.

I "Micro adjusted" (just found out this morning that's the term for indexing on Di2) this morning using the eTube software. It was already accurately adjusted and that didn't change/remedy the issue, thought that's a cool Di2 feature I didn't know about before.

Just a thought, but do you know all those wheels and trainer put the cassette in the same position with respect to the DR?

Is the one that you had on it when you adjusted the positions the quiet one or was it noisy too?

Noise like this is usually caused by the chain binding or not lining up with something, like a chainring, a cassette cog, or a derailleur pulley. On some of these I've noticed a slight twist in the derailleur cage, i.e. the pulleys are not in line with the chain/centerline of the bike. To test this, first determine if it gets quieter in different gear combinations. You can also eyeball this alignment from above. Finally, you can impart a slight twist in the cage with your hand as you pedal on the stand. Do that in a gear combination that puts the cage in a vertical orientation. If that quiets it, give it a permanent gentle twist with an adjustable spanner.

Something else I've seen for which I've caught hell on this forum is the derailleur pulleys not being in line. That is, the lower (tension) pulley was cocked out because of a slight bend in the cage. Somebody tried to convince me it was normal. It isn't. If that's the case consider warrantying the derailleur against trying to straighten it yourself.

I guess my answer is that I don't know enough to know. My thought is that (at least in theory) the trainer and both wheels should put the cassette in the same place in relation to the the derailleur. But, in the real world I would imagine each has some level of error in manufacturing that would cause some discrepancies.

My intent in trying different wheels, cassette, and the trainer was to try and narrow down whether I had a wheel problem, a cassette problem, or none of the above. At this point I'm leaning towards it being something other than the wheels or cassettes themselves as the sound varies across the two different wheels and the trainer, but it is universally noisy across all 3.

I think the most likely scenario so far is slight twist of the RD cage and / or misalignment of pulleys….

All I hear is your chain on the last video. There was a recent thread where someone wanted to know what the buzzing sound was when he was in the small cog. The chain links are a certain size and when it goes around a small cog its going to articulate more and buzz a little.

On your other two videos, a couple things to keep in mind for anyone listening. The sounds are very pronounced and louder on video. This includes the act of shifting where you will hear a loud "thunk" and the sound of the trainer itself. Keeping that in mind, it sounds like the chain may be contacting your front derailleur when you are pedaling.

Looks like you both are thinking the same thing.

I looked and didn't notice either of those as the case, and did some twisting on the derailleur cage with no improvement, but I'll give that some more time this evening.

Thanks for the responses/ideas!

I concur that in the last video (with the Ican wheel) it is mostly the chain sound (the point of that video was to contrast it with the other wheel in the same gear).

There is an abnormal drivetrain noise and pulsing (when compared with another Ultegra setup). It's probably best reflected in the video on the trainer at about 12 seconds (and the sound goes away after a shift at about 20 seconds. I took the bike out for 50 miles today and the noise is definitely present on the road. It's not horrific and I may need to just let this go and ride, but I believe the problem is fixable; just not sure that my experience/knowledge level is capable of fixing it.

I checked, the chain is not contacting the front derailleur.

Appreciate the suggestion!

A friend had something similar, and the problem was the chain routing through the rear derailleur. It was in the wrong side of a metal tab, and each link had to slide over it.

​​​​​​THis seems like a large enough error that it would be obvious, but it isn't. He had taken it for 1-2 mile shakedown rides and the extra drag wasn't so much scream. "wrong wrong", just enough to be noisy.

Something to check...

Appreciate all the recommendations; I’ve tried/checked everything listed and can’t find any issues/defects.

I did find that this seems to be a known/common issue (one of several threads I found): https://weightweenies.starbike.com/f...p?f=3&t=151935

And it seems numerous people are finding a resolution through using a 12 speed Shimano XTR chain. So I’m going to give that a try.

Hey,
my Ultegra Di2 drivetrain is making the same noise. Did switching to a 12 speed chain fix it for you?