Rough drive train issue

[EG]

I’m having an issue with my newly built Sam Hillborne and looking for thoughts on how to correct it. During the downstroke of both pedals I can feel this sort of clicking sensation in addition to a rumbling or vibration. It seems to be most prominent in the middle of the cassette and in the higher gears. I don’t hear any sound and it doesn’t occur when in the stand. The components are Deore xt rd, cx70 fd, 9 speed shimano cassette, New Albion “Clipper” double crank (42 x 30).

Fortunately, I live next to a bike coop in SF so I’ve been able to swap out a bunch of parts to try and narrow it down... it does not seem to be the rear or front derailleurs, cassette, hub, chain, or pedals because it persists when each is replaced individually. I asked Will at RivHQ and he said that sometimes the 9-speed setups have this issue and it goes away with time. I have only put ~300 miles on it so still pretty fresh, but I was wondering if anyone had this experience or any possible solutions. Overall the bike rides great and mechanically everything seems to be fine, just this nagging sensation through the pedals. Any ideas?

[Joe Bernard]

I've had this with certain 9-speed chain/cassette combos, I can't remember which brands of each have this mating issue. I think Will is correct that they will bed in over time and the problem will go away.

[Alex Wirth- Owner, Yellow Haus Bicycles]

I’ve also experienced this and my interpretation is that the chainrings need some time to get rid of their "rough” edges (from machining?). Maybe someone with a background in tool making can chime in on the manufacturing processes and postulate on that?...

I’ve only noticed it on low to mid grade cranks. Almost always on Sugino 9 sp.

And it always feels gross...but eventually goes away.

[Kevin Mulcahy]

Questions like this are best answered at your LBS, not over the ‘net. I’m sure an experienced mechanic could pinpoint the issue in a matter of minutes once they get one the bike.

[Eric G]

I agree — I started by taking it to LBS and did not get an answer. Then I took it apart piece by piece and put it back together which also didn’t give me a definite answer. Then I took it to RivHQ and Will suggested it just needing time to break in which seems entirely plausible. Figured I would post here to garner the collective wisdom of folks with similar bikes that may have experienced a similar issue which has so far been reassuring.

[David Carner]

I have had a similar problem with my 2010 Sam. A little different in that it is most noticeable on the drive side down stroke and particularly when spinning when not climbing. I put it down to poor peddling technique until it got worse. After making sure it was not a crank issue I have determined that there is play between the hub body and cassette; radially, not laterally. For the first time ever I actually used a torque wrench to tighten the lock ring to the specified torque and that has stopped it for now. The cassette is 12-36 Shimano and hub is Deore, both from RBW.

[Eric G]

This weekend I decided to replace my bottom bracket to try to fix the problem since it is a relatively cheap part (Shimano UN-55). I haven't ever done it before so I figured it would be a fun exercise. The original size turned out to be a 110mm while the replacement was 113mm. The threads in the bottom bracket shell were a little gunked up so I cleaned it out and replaced the BB, tightening with a torque wrench to the specified torque on the BB and crank bolt.  The grinding sensation in the pedals went away entirely. Was it the bottom bracket itself, gunk in the threads, or chain line? I don't know and I'm not sure that it matters, but I figured that I would update the thread for posterity's sake. 

[PaulS]

How old was the bottom bracket? Those Shimano sealed units usually last a very long time. So if it was new and I abused, I’d probably say it was the gunk. I’ve had creaks and groans from dirty BB shells.

[Eric G]

The BB was brand new and installed by a reputable shop. I don't suspect there was anything wrong at all with the BB since it only had ~500 miles on it. I suppose I could have sorted that out by reinstalling the BB after cleaning the threads, but alas, I didn't. 

[Joe Bernard]

Did you use the repair bay at Missing Link? That's where I learned to work on bikes before I had my own tools.

[Eric G]

No, not the Missing Link. It is called the Bike Kitchen and is located in the Mission. http://bikekitchen.org/

[Chris Corral]

Sounds like chainline to me. Without seeing the bike in person and assuming everything was tightened correctly, my guess was going to be the chain was running rough. FYI I have also noticed some chains are louder than others; for example, KMC 9 speed chains are generally louder on Shimano cassettes than SRAM. For my 10 and 11 speed Shimano stuff, I've been using Shimano chains and performance is great. KMC is okay, maybe last a little longer.

Experiment for yourself. There are a lot of variables as I'm sure you have realized by now.

[Toshi Takeuchi]

I am having this problem with one of my bikes with a few cogs on the cassette.  I think it's a chainline issue that occurs with one of my rear wheels.  I'll try applying a little more torque on the cassette lock and see if that helps (good tip from a previous poster).

Toshi

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[Paul G]

I, too, am having this issue. For me, it happened after going from an Ultegra 10-speed chain and cassette to a KMC chain and MicroShift cassette, both in 9-speed. However, the "grinding" sensation didn't happen immediately, but after about 150-200 miles (after the first chain re-lubing with Boeshield I might add).

It's become annoying and maybe I should have stayed with the 10-speed stuff but I drank the "9-is-all-you-need" Kool-aid...especially so since the current 9-speed setup friction shifts worse than the former 10-speed stuff did even though it's not suppose to.

I'll also check the cassette lock ring torque before I complain further.