Ryan_M

My bike came with a 2x10 M6000 RD and cassette with a KMC chain. I noticed from new there was a lot of noise from the RD, everything was adjusted right and it didn't sound "bad" mechanically, just louder than expected. It sounds like the chain noise as it goes over the jockey wheels. It was my first mountain(ish) bike so I sluffed it off that's what MTB drivetrains sounds like. I ended up upgrading to a full M8000 2x11 drivetrain and was shocked by the difference, now it's nearly as quiet and smooth as a belt drive! Love it!

My old parts got rehomed on my GF's bike to give her an upgrade and the RD sounds the same. I'm wondering if the M6000 RDs are known for this?...or what it could be? Are the M8000 jockey wheels that much better or could the KMC chain be the culprit? Everything works just fine, I'd just like to quiet it down if only for my own sake since I have to ride beside her sometimes LOL.

ClydeClydeson

Are you sure the chain is routed properly through the derailleur cage? It is possible to route it through such that the chain drags over a little tab, but otherwise looks correct unless you are looking for that particular mistake.

cobba

Photos might show a problem.

hokiefyd 

If the M6000 drivetrain was new, and the chain was new and still had the factory schmoo on it, then it should have been remarkably quiet...if the chain was routed correctly. As long as the derailleur is adjusted and indexed correctly (and the chain is routed correctly), then a KMC chain shouldn't run any louder or quieter than any other brand of chain (when new). Of course, as chains wear and lubricant disappears, they get louder. Restoration of that lubricant (liquid, wax, whatever you use) should return the chain to being quiet again. Some lubricants tend to run quieter than others, and this shouldn't turn into a this lube vs. that lube discussion...the point being any new drivetrain should sound pretty darn quiet as long as everything is adjusted and installed correctly.

I agree that photos (or even a video!) of the system on its new host frame would be helpful.

cxwrench

Gotta love these 'what's wrong w/ my bike' threads that have no photos.

Ryan_M

Yeah I know that's not it. I accidentally routed it like that when I was putting the parts on her bike, at least I cought it before I put the chain back together.

It's done it since new. Obviously the LBS would have adjusted it when new, I readjusted it after the first few rides, and it's been moved to another bike, all the same sound. We're pretty diligent about cleaning and relubing too. I don't have the bike in my possession since it's at her place. When I get it I'll put up some pics and see if I can get a video up if my phone will capture to sound well enough.

​​​​​​​I was initially curious if this was a known issue with the M6000 RD or KMC chains to see if this needed further investigation. It appears it isn't normal so I'll post more info when I get it.

ARider2

I suggest you remove the chain and carefully inspect the derailleur jockey wheels for abnormalities. Spin them and see how they feel and sound. Also check the derailleur alignment and whether the upper and lower wheels are on a parallel plane when viewing from the rear and when shifting from the small to large cogs.

Ryan_M

I finally got her bike in my shop so I could take a video of the sound differences. Unfortunately I won't have time to get into anything this time before she takes it home again. I took a video of my M8000 drivetrain to compare to her M6000. To take the vidoes I mounted my phone on a tripod the same distance away so the volume would match. Both bikes have approx the same use (~1500km) though the M8000 has probably had a bit rougher life lol.

M6000 Drivetrain

M8000 Drivetrain

cxwrench

That may be the most useless video ever. Yes, we can hear the noise. But we can't see anything that might help figure it out. Her bike has a bigger cassette...is it a b-tension thing? Hanger bent?

oldbobcat

Check the chain line. Does it make noise in all rear cog positions? Is the nose any different when using the big ring vs. the small ring? Eyeball the chain passing through the derailleur and the cassette cog directly from behind. does the chain form a straight line as it passes from the tension pulley through the jockey pulley (terminology here: the jockey pulley is closer to the cogs and "jockeys" the chain back and forth, the tension pulley keeps the chain taught) through the cassette. When not shifting, does the chain pass directly over the center of the pulleys and cassette cogs or does it favor one side? Does the sound change if you apply hand pressure to inside or outside of the entire derailleur? And finally, does the derailleur shift OK? I'm assuming the chain and cassette are both fairly new.

curbtender

I'm going with the b-tension thing. That pulley on the 6000 looks like it's almost right on the cassette.

Racing Dan

Often noise is from the B-screw not being tight enough, causing the guide pulley to slightly rub on the cassette.

Ryan_M

It was mentioned earlier in the thread that there should not be a significant audible difference between the two drive trains. The only point of those two videos was to show there is indeed a significant audible difference. ???! They are both 11-42 cassettes. Both videos were shot with the chain on the 21T cog to give a straight(ish) chain line and both cassettes have this cog in common. I don't believe it is a b-screw thing. Shimano specs a ~5mm gap between the largest cog and the guide pulley. I find at that setting the chain can occasionally have a hard time climbing onto the largest cog, adjusting the b-screw to increase the gap to ~10mm ameliorates this. Visually the hanger looks fine and everything appears to be in alignment.

The sound changes slightly depending on the chanring/cog combination but is otherwise consistent. Its funny you mention the chain line, when intitially inspecting it I noticed there appears to be a very slight offset between the tension and guide pulleys and the chain favours the inboard side of the guide pulley when coming from the tension pulley. However, examining the diagram in this document (bottom of page 13) this is actually normal. Oddly this situation is more evident in the M8000 RD except it's the tension pulley that is more skewed, as can be seen in this document (bottom of page 11). I did try tweaking the RD and cage by hand to see if it had any effect on the sound, it didn't. Yes the drivetrain is fairly new and shifts perfectly fine.

One thing I noticed after watching the videos a bunch of times is if you follow the line of the chain pins there appears to be a vibrational pattern that sets up in the chain between the tension and guide pulleys on the M6000 video nut not the M8000 video. Going to the bike and looking specifically for this I can confirm this is what I'm seeing and not a trick of the camera. Maybe those videos weren't so useless after all lol!! I've been waiting to start taking things apart as I have a M6000 crank to install on her bike as soon as I can get a BB. I ordered one from China and nearly 8 weeks later when the package arrived there was no BB in the box. Ordered a second time and found out 6 weeks later the seller cancelled the shipment. I then ordered one from a place here in Canada that listed it as in stock but 2 weeks later still no BB grrr! Sorry for the rant. I was going to get into figuring this out now since riding season is getting close but there's a couple nice days expected before the temps go below freezing again so the bike went home and it'll be another couple weeks before I can revisit this. I'm going to see if I can't swap jockey pulleys to try to prove or eliminate them as the source. I'll be very surprised if they're the issue as in 30+ years of woking on bikes I've never had a problem with jockey pulleys but so far the evidence seems to be pointing to them.

That's just an illusion of the camera. The video was done on the 21T cog so there's lots of space between the guide pulley and the cog. I took a picture to show that. My bad, I should have included more detail with that post.

Iride01 

I'm not the type that gets upset and angry when a bike is turned upside down, but for adjusting things, upside down is wrong. Gravity is pulling the wrong way on some of the stuff you are adjusting.

As for noise, does it make the noise when right side up?


Also wondering if those are the right size pulley/jockey wheels. But too lazy to look up that DR right now.

Ryan_M

Yes and no. My bike is seemingly unaffected with being upside down or not but hers most certainly is. I suspect the difference is my bike has unbroken casing all the way from the shifter to the RD, hers has in frame routing so there's a short piece of casing from the shifter to the side of the downtube then bare cable through the frame, over a guide on the underside of the BB, then through another short piece of casing close to the RD. What a horrible system!!! Not only does right side up or upside down slightly affect settings but having weight on the bike makes a difference as well, presumably because any slight flexing of the frame will have a dirrect effect on the cable. Also having my weight on the bike will change the indexing setting compared to her weight on the bike albeit very small. So when tweaking the barrel adjusters at the shifters looking for perfection it has to be with her riding it and me riding beside her listening to and watching the shifting action and talking her through what adjustments to make. Again horrible!

So I do agree with you it can have an effect in some situations, however it isn't in this case. The RD makes the same noise regardless of orientation or if I'm riding the bike and have the shifting dialed in perfectly. It also made the same noise when this RD was on my bike.

I can't see Shimano installing wrong parts at the time of manufacture but stranger things have happened. I'm not sure how I'd confirm that. The tech document shows they are directional so that'll be something to look for when I get a chance to take it appart. Thanks!

curbtender

I have a stethoscope I use to find noise issues. You can do the same with a vacuum hose.

Iride01 

I don't see Shimano putting the wrong size wheels on the DR either. That was added just to make sure you or someone else hadn't changed them as to me they looked a little small for that long a cage.

From some of the tidbits you keep adding, I think there may well be more than one issue. And I don't know where to start other than tell you to either go to a LBS that has a decent mechanic or go through the Shimano DM's an SI's for your stuff and make certain everything is as it should be. https://si.shimano.com/#/

I've been thinking you simply have the chain run wrong on the DR pulley wheels and it's hitting that little tab, but from the pics it doesn't look wrong.

oldbobcat

Your big cog looks worn out relative to the chain. I'm seeing long u-shaped valleys between the teeth and a little bit of blue sky where the chain meshes with the teeth. Also the bottom end of the cage (the end that holds the tension pulley) appears to be tweaked outward a little bit. It's as if the chain isn't running a straight line between the two pulleys. Check these out.

Ryan_M

Why would you think that? A pic of a brand new cassette (see below) shows the same elongated valleys, plus in a couple of my pics you can see across multiple teeth that the plating isn't even worn off yet on the major wear surfaces. What do you estimate the thickness of the plating is? 0.001"? likely less? i have significant doubts that less than 0.001" would be beyond the wear limit for that cog. Given that that particular cog probably has less than 5km of use would also speak very poorly about Shimano's durability.

Yes the cage does have some odd tweaks to it. You're also correct the chain is not running in a perfect straight line since the guide and tension pulleys are not coplanar. This is all normal according to Shimano's documentaion as was covered in the post you quoted.

I'll appologize now, sorry to call you out like that. I really do appreciate the effort but before you post something make sure it's even correct and relevant, or hasn't already been covered. This isn't 100% directed at you, it's just frustrating. Alignment has been brought up so many times. That's already been checked, double checked, visually compared to Shimano drawings, and tweaked both mechanically and manually to rule it out before this thread was even started. Unless somebody has an idea how I can sneak a dial gauge onto that tension pulley AND has dimensioned mechanical drawings with tolerances from Shimano to compare with I don't think think there's any farther to go with that. I love that after cxwrench's snippy remark the video is actually the only thing so far that shows some proof that theres something weird going on around the jockey pulleys. Speaks volumes to his analytical prowess and his elementary math skills (since by his calculations 11-42 is bigger than 11-42) - LOL hey dude if you're gonna dish it out you gotta be able to take it too haha. Until I can get the bike back in my shop, get some time with it, and swap some parts, this is kinda at a stand still.

oldbobcat

Thanks for posting the photo of an unused 42t cassette. Relative to more normal-sized cogs, the valleys between some teeth appear elongated. Perhaps this is an accommodation for 42 teeth. As for the tweaking of the derailleur cage, yes, the documentation does show a curve at the bottom of the cage itself. It does not indicate that the pulleys should be out of line with each other or the cassette cogs, and this was the discrepancy I was trying to alert you to. The axes of the axle and the two pulleys need to be parallel and to my eye the tension pulley looks a little cocked. My advice was for you to check it.

I apologize for not being able to diagnose this problem perfectly for you from your photographs, videos, and descriptions. You indicated at the start that you had no idea. Others have responded with their suggestions with no apparent success. This tells me it's pernicious and we have to start looking under rocks. I've successfully diagnosed and remedied drivetrains with similar issues, and I have to tell you it's not a cut-and-dry procedure. You look for clues and you test them, and if that doesn't work you look for more clues. And you don't beat yourself up for following a dead end. And it's considerably easier with the bike in the stand than with photos and videos and a customer second-guessing everything you try.

If you think my advice is a dead end, then ignore it. It was offered with good intentions.

Ryan_M

Sorry forgot to follow up on this... So I had a chance to spend some time with the bike and tried a few things. I swapped the chains first . My HG701 chain was more quiet than the KMC, not a whole lot but I could hear the difference on the bench. Probably wouldn't equate to much real world gain if even noticable on the road though the tone of the sound was slightly less objectionable. I then swapped the idlers. The Deore idlers use bushings and have some 'slop', which I've read is intentional to aid with shifting, the XT idlers have bearings and little friction to them just enough to not be rattly. These made a big difference in the sound, not as good as on my bike but close. I noticed the same resonance between the pulleys as before so that must be something to do with the distance between the pulleys and being a close multiple of the chain pitch. I don't intend to explore this further since it's not really fixable.

In the end I tried a thicker sticky grease in the Deore idlers to simulate the light friction of the XT idlers and it worked great. Again not as quiet as my drive train but easily an improvement.

70sSanO

Hate to break this to you, but your M6000 drawing (pg13) shows the centerline going through the top and bottom pulleys with the pulleys parallel. It is drawn that way to show they are on plane.

If your M6000 isn’t straight I doubt it was designed that way. Also 10 speed systems have been around forever without having to tilt the tension pulley to accommodate the cross-chain angle, especially on a 2x10.

You M8000 drawing (pg11) shows the tension pulley skewed, and slightly skewed for the guide pulley, from the centerline and not parallel. I don’t think it looks that way because the engineer was having a bad day.

But I’m glad it is running a little quieter.

John