Drive train noise and vibration

Discuss light weight issues concerning road bikes & parts.
sennder
Posts: 111
Joined: Mon Aug 08, 2016 12:13 pm

by sennder

Hello forum,

My problems with my Trek Domane SLR with R8000 groupset continue. After my failed warranty attempt, I had to rebuild the bike. Now,the drivetrain has became extremely noisy and started vibrating at higher gears.

All adjustments are on point (limit screws front and back, B screw, cable tension). All the parts have less than 500km on them (indoor and outdoor combined). Drivetrain was cleaned and relubed two days ago. Chain length is perfect. Shifting is smooth, fast and precise, both front and back. Now the issues:

1. 4th-11th gear on the big ring causes rattling on the back. It sounds like a worn out chain or cassette but both have less than 500km on them. On the smaller ring, the same noise is there but it's significantly lower. I thought it was the rear cable tension but the noise is consistent with adjustment of the barrel adjuster.
2. 10th-11th gear, the drive train sends sharp vibrations up the seat tube, possibly originating from the bottom bracket area. This vibration is repeated with every crank rotation. It almost feels like rattling. The FD is not touching the chain at all. I redid the crankset just to be sure and it's seated perfectly. It spins just fine in other gears (120+ cadence in lower gears). The chain also seems to bounce up and down a bit on the top (between the crankset and the cassette, not due to the rear mech).

Both noises are present without any load on the rear wheel (on a trainer without the resistance block in contact). Shifting is perfect and fast between all gears and on both chainrings.

Has anyone experienced anything similar? Could it be a misaligned rear derailleur hanger?

Thank you!

--Sennder

Attermann
Posts: 384
Joined: Sun Jan 05, 2014 11:04 pm
Location: Denmark

by Attermann

The chain is not on the wrong side of the tap on the cage?

by Weenie


alcatraz
Posts: 2201
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

Is it possible the chain tension is too high?

What about your indexing? Is it spot on? Check the r8000 manual.

Eyeball the angles of your upper derailleur pulley. Is it perfectly in line with the cogs of the cassette horisontally and vertically?

Is it an 11s chain you are using? Is it worn out? Maybe check that you havent accidentally put a different chain.

Check for play in your cassette and crank by trying to moving it laterally. They should be solid and not move.

/a

NickJHP
Posts: 266
Joined: Wed Feb 14, 2018 2:22 am
Location: Canberra, Australia

by NickJHP

What size cassette are you using? The 11-34 available with the latest Ultegra group requres a spacer behind it when installed on an 11-speed freehub, as it's like the MTB cassettes in that it will fit on an 8/9/10-speed freehub. Also check you've installed the chain the correct way around (the lettering on the sideplates should face outwards).

Stitchking
Posts: 175
Joined: Fri May 25, 2018 7:30 am

by Stitchking

Sounds like your chain is upside down/back to front. Also, measure your chainline. Should be 46mm from middle of seat tube to outer chainring

Sent from my SM-G935F using Tapatalk


sennder
Posts: 111
Joined: Mon Aug 08, 2016 12:13 pm

by sennder

Attermann wrote:
Tue Jul 17, 2018 7:17 am
The chain is not on the wrong side of the tap on the cage?
Confirmed that it is not. I actually pulled it out of the cage (by removing the lower pulley) to make sure that the rear mech was aligned perfectly.

Thanks!

sennder
Posts: 111
Joined: Mon Aug 08, 2016 12:13 pm

by sennder

alcatraz wrote:
Tue Jul 17, 2018 7:42 am
Is it possible the chain tension is too high?

What about your indexing? Is it spot on? Check the r8000 manual.

Eyeball the angles of your upper derailleur pulley. Is it perfectly in line with the cogs of the cassette horisontally and vertically?

Is it an 11s chain you are using? Is it worn out? Maybe check that you havent accidentally put a different chain.

Check for play in your cassette and crank by trying to moving it laterally. They should be solid and not move.

/a
Chain tension seems fine. Any shorter and the rear mech will be completely stretched out in the largest cog and chainring. Any longer and the chain will touch the top pulley of the cage in the smallest cog and chainring.

Indexing is fine. As I mentioned, shifting is perfect, which is what makes the situation so confusing. I did followed the R8000 dealers manuals for that.

I'm not sure what you mean by that. I confirmed that it's perfectly aligned with the cassette in each gear (by removing the chain from the cage and adjusting the barrel adjuster). I also adjusted the B screw to leave ~5-6mm gap between the teeth of the largest sprocket and the top pulley of the cage. Am I missing a rear derailleur adjustment?

Chain is the 11s one that I got with the groupset. Not particularly worn out. I've ordered a replacement online anyway since I did have to open a link when I disassembled the bike for the warranty claim.

I suspected the cranks for the rattling problem and did end up removing and reinstalling them. No play at all. Cassette and freehub have no play either.

Thank you!

sennder
Posts: 111
Joined: Mon Aug 08, 2016 12:13 pm

by sennder

NickJHP wrote:
Tue Jul 17, 2018 7:53 am
What size cassette are you using? The 11-34 available with the latest Ultegra group requres a spacer behind it when installed on an 11-speed freehub, as it's like the MTB cassettes in that it will fit on an 8/9/10-speed freehub. Also check you've installed the chain the correct way around (the lettering on the sideplates should face outwards).
The cassette is 11-28 and chainrings are 52/36, so I think I'm good there.
Stitchking wrote:
Tue Jul 17, 2018 8:52 am
Sounds like your chain is upside down/back to front. Also, measure your chainline. Should be 46mm from middle of seat tube to outer chainring

Sent from my SM-G935F using Tapatalk
I'll measure the chainline. If it is off, will I require a spacer on the crank axle (I'm pretty sure the BB bearings came with a few)?

As for the directionality of the chain, I was pretty sure that I had the HG701 chain, which I believe is non-directional. But now that you both have mentioned it, I'll check that I don't have the HG700 (directional) chain instead, and confirm that I have it in the correct direction.

Thank you for the suggestions!

NickJHP
Posts: 266
Joined: Wed Feb 14, 2018 2:22 am
Location: Canberra, Australia

by NickJHP


sennder
Posts: 111
Joined: Mon Aug 08, 2016 12:13 pm

by sennder

NickJHP wrote:
Tue Jul 17, 2018 9:59 am
The HG701 chain is directional: https://bike.shimano.com/en-EU/product/ ... 01-11.html.
That's interesting. I recalled that CN-6800 was non-directional, it's replacement CN-HG700 was directional, and released shortly after CN-HG701 was again non-directional. I guess I was mistaken. Thank you for correcting me!

However, it seems that without even following the 11-speed chain manual, I got both the direction and the orientation correct. I have the text on the outside and the outer link on the front end of the chain in the direction of movement at the connecting pin, as shown on page 5 of the manual.

Thanks!

--Sennder

sennder
Posts: 111
Joined: Mon Aug 08, 2016 12:13 pm

by sennder

Stitchking wrote:
Tue Jul 17, 2018 8:52 am
Also, measure your chainline. Should be 46mm from middle of seat tube to outer chainring
By my measurements, the chain line, measured between the center of the bottle cage bolts (the seat tube is asymmetric so I'm taking that as the center of the tube) and the outer chainring is 48.5mm +/- 1mm. It is definitely more than 46mm. The only way the chainline can be 46mm is if the bottle cage bolts are offset towards the non-drive side. My R8000 crankset is pretty much flush against the BB shell. I have no spacers installed. Just Endura bearings (37x24x7mm) and the outer seals. There's no play in the crankset.

Could this be an issue?

Thanks!

--Sennder

mattr
Posts: 4673
Joined: Fri May 25, 2007 6:43 pm
Location: The Grim North.

by mattr

Unlikely. Not the way you describe the noise anyway.
With a too large chain line it'll be noisier in the smaller gears. I.e. when cross chaining in the big ring or grinding up steep hills in low gears. And with a difference that small, it's *Unlikely* to be noticeable unless something else is going on.

mattr
Posts: 4673
Joined: Fri May 25, 2007 6:43 pm
Location: The Grim North.

by mattr

TBH it sounds like a twisted hanger. Rather than bent.
You can get it to shift well, so it's not simply bent. But there are certain combinations of twist/bend that you can get good shifting with.

sennder
Posts: 111
Joined: Mon Aug 08, 2016 12:13 pm

by sennder

mattr wrote:
Tue Jul 17, 2018 10:50 pm
TBH it sounds like a twisted hanger. Rather than bent.
You can get it to shift well, so it's not simply bent. But there are certain combinations of twist/bend that you can get good shifting with.
Hmm. That's actually a very good point. That was the one of the things that I "checked". I removed the derailleur and the hanger to see if I had accidentally damaged it while tightening the cable pinch bolt. I used a torque wrench to tighten the pinch bolt but the bolt is all twisted up because of the new RD design so the angle of the wrench might have added undue stress on the hanger. I didn't notice anything immediately wrong with the hanger from eyeballing it, but I suppose it'll be hard to tell without a derailleur hanger alignment tool.

If there is a small twist, is there any way to confirm before I purchase a new hanger? I suppose I could take it to the shop but I feel that buying and installing a new hanger will be cheaper.

Thanks for suggestion!

--Sennder

alcatraz
Posts: 2201
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

I wrote to you about checking the hanger.

You can use the eyeballing method I mentioned, but make sure you check from behind the bike and from under the bike with it flipped upside down.

In two planes. Look only at the upper derailleur pulley. It needs to be perfectly parallel with the cassette.

When you tighten your rear wheel skewer you can change the hanger angle. Make sure your pressure is consistent, then do the checks and indexing adjustment, hanger adjustments. Also make sure the wheel is deep in the dropout before tightening the skewer. It will affect shifting because the cassette can change it's angle to the derailleur.

If you are reusing a shimano chain is it possible you've shortened it the second time and put a quick link on? Noise can occur when the chain tension is high. (The B-screw on the derailleur should not really be used for chain tension adjustment but to make sure the upper derailleur pulley is the right distance from the cassette. Set that screw low enough so that you don't have clearance issues on the big cogs. If the chain is too long and touches in small/small you should maybe take a link out. Depends on how much you were off with the B-screw.)

When the wheel is off you can try to feel if your wheel bearings are gritty. It's possible your freehub bearings aren't ok, or properly preloaded so when the chain pulls on the end of the cassette it rattles or moves around a bit. Play should be zero. But you checked that.. just saying it could be likely.

by Weenie


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