Dholton3

Hey all,

I'm posting here on Bike Forums to see if anyone may have a clue as to what my issue is; I posted this to the r/bikewrench sub****** a few days ago, and while there were some good tips/suggestions, I can't seem to resolve my issue. Basically, I keep getting a really loud, metallic sound from the rear of my bike when pedaling (it sounds like the when the gears are misindexed and they're trying to jump from cog to cog, except they are indexed properly). This happens more or less in most of the gears, but is the loudest when in the lower half of the casssette (19t cog-11t cog), and when substantial torque is put through the cassette. I wanted to ask y'all if there were any other opinions, because the noise has only gotten worse in the days recent, despite me trying/troubleshooting a couple things:

1. I first grabbed an old wheel I had in my storage closet and just for kicks, threw it onto the bike. Lo and behold, no noise when pedaling. I then took off the new cassette and fitted it to the old wheel and installed the old wheel onto the bike. Again, no noise when pedaling. Finally, I took the old cassette from that old wheel and installed it onto my current wheel, and this time it was noisy (same metallic crunching sound). This leads me to believe the issue is isolated to the wheel itself, not the chain or cassette.
   
2. I brought the bike into the shop a couple of days ago, and a really helpful mechanic ran through all the 'normal' things that may be causing the noise (e.g. checking if cassette lockring is tight, b-tension screw, etc.) He did end up straightening out the derailleur hanger (as well as noticing I had incorrectly routed the rear shift cable around the bolt, dumb me), and at first I thought that was problem solved. However, upon arriving home and pedaling the bike around, the noise is still there.
   

Again, I will note the sound is really extreme in the lower half of the cassette (19t cog down to 11t cog); the reason I say this is because when I remove the cassette from the freehub body, I notice the freehub body has (very small) notches in it from what I presume is the cassette "biting" into the freehub body. The notches are only in the 'bottom half' of the freehub body (where the 19t cogs and down would be engaging the freehub body). But I've read online (as well as having been told by the mechanic) that this is fairly common and shouldn't result in any noise. So basically, I'm stumped. My feeling is that the notching in the freehub body (although very small), must be accounting for some noise. Either that or the bearings in the freehub are shot or something, but would that really account for noise when I'm pedaling?

Some final things:

1. No noise (besides the buzzing of the freehub) when coasting; it's only when pedaling, and the noise gets louder when more force/power is applied to the pedals.
   
2. The chain, cassette, and pulley wheels are all brand new and are like-for-like parts as what was originally on the bike (e.g. same 11 speed Dura-Ace chain, same 11 speed ultegra cassette, same Dura-Ace pulley wheels).
   
3. Just today, I removed the freehub body from my rear wheel and degreased/re-applied new grease to all the parts (freehub body itself, ratchets, etc), and while the freehub does sound quieter when coasting, the sound when pedaling still remains. Rear wheel is a Roval CL50 with DT Swiss internals, sealed cartridge bearings (I did not touch the bearings).

If you've gotten this far, appreciate it you sticking with me. Any tips or recommendations are greatly appreciated, cuz I'm stumped!

N2deep

It appears that you have eliminated the rear wheel and rear derailer. My bet would be the bottom bracket bearing.

Dholton3

So the thing is I'm pretty sure that the noise IS a result of the rear wheel, since when I fit my other wheel onto the bike, the chain/cassette noise goes away. Regardless of which cassette I put onto my Roval rear wheel, I get the same chain/cassette noise no matter what. I would assume that if it were an issue with the BB, I would get noise regardless of which rear wheel I had on the bike, but I could be wrong.

CliffordK

Hmmm... tension on the lock ring should help prevent the cassette from biting into the freehub.

With the cassette locked in place, can you twist or wiggle any of the sprockets?

When you had the freehub off, did you feel all the bearings to verify that they all turned very smoothly?

Dholton3

Lock ring is indeed tight, I don't have a torque wrench to verify it's exactly at 40 Nm, but the mechanic at the shop told me it's indeed tight, and there is no play in the cassette/individual cogs, so I don't believe it's an issue with the lockring being too loose. I didn't check the freehub bearings, they are sealed cartridge bearings, do I just trying turning them by hand with the freehub off? I don't want to even attempt to open up the bearings cuz I'm scared I'll mess something up haha...

CliffordK

If the lock ring bottomed out for one reason or another, it could be tight without the cassette being tight. But, that doesn't seem to be the case.

Yep... just stick your finger in and see if the bearings turn smoothly.

I don't believe taking sealed bearings apart is easy, although Mom had a wheelborrow bearing that exploded in an interesting fashion.

Dholton3

So I took off the freehub body again to check the bearings, turned just fine. After work today, I took the bike into another LBS nearby and gave the mechanic the rundown of everything; he said everything looked immaculate besides the chain slightly rubbing against the FD cage in the smallest cog(s), but we both agreed that that couldn't be causing the noise all the way up to the 19t cog. He took the freehub apart and regreased everything while I was there, and although the freehub sounds much quieter when coasting, the noise is still there when pedaling under load. At this point, I'm completely stumped as to what is causing this noise. The new cassette works/is quiet when swapped to my other wheel, so I'm almost positive the noise is wheel related. What else related to the wheel specifically could be causing the noise?

CliffordK

Are you feeling any skipping? I'm not sure what an internal freehub skip would be like. I'd expect it to spin, but perhaps one could have multiple single tooth releases.

Dholton3

Nope, no skipping of the gears, just the same, metallic grinding sound when pedaling,

nathand

When you've taken it to your LBS, can the mechanic hear the noise when the bike is in a stand?
Have you checked the hub of the problematic wheel carefully - not the freehub but the rest of it? Wondering if you've got a cracked flange or loose spoke that only gets noisy when there's both weight on the wheel and drive tension on the spokes.
Do you feel any roughness coming through the drivetrain to your feet on the pedals when it's making this noise?

Dholton3

There is a little bit of roughness that I can feel through the pedals when pedaling, yes. Kind of like a gritty/grainy feeling in my feet when applying power through the pedals, yeah. I haven't checked the hub itself in detail, the most detailed I've gotten thus far is taking off the freehub body, ratchets, and endcap, and degreasing/regreasing and reinstalling. To no success. I don't have a bike stand at home, but I can hear the noise when I flip the bike over on the ground and pedal; it just gets louder when I'm actually riding the bike and applying more power to the pedals. I've checked the spoke tension and they all seem fine/wheel is true; I actually had several of the spokes on this wheel replaced a few months ago (one of them broke during a ride, went to LBS to get it replaced, they ended up replacing around 8 spokes or so because some of them were damaged from chain getting jammed in wheel once). Dumb question: how would I check for/notice a cracked flange?

Crankycrank

Has anyone checked the derailleur pulley cage to see if it's bent from your chain getting jammed in the wheel? Even with the hanger alignment checked the pulley wheels could be at an angle and causing a grinding sound.

zandoval 

I had an old steel wheel on a 70s UO-8. The bike had been left outside in Galveston Texas air and almost all of it was well rested. The owners husband had slobbered the entire rear wheel and freewheel with Marine Grease so it actually looked pretty good after I got all the dirt off of it. I too had a strange sound coming from the wheel when under strain but it was a long wait before I could afford a wheel set so I babied it along. Oddly one morning, as I got off to class, I noted three spokes popped on the rear wheel. When I took the wheel off to repair I noted it was headed for a catastrophic failure. The rim was literally coming apart. The inside of the rim and bead were rusted through. Also the weld holding the wheel to round was cracked. It was a nice looking wheel but totally toast on the inside of the wheel lip.

It looks like you have isolated the problem to the wheel. There could be small cracks in the alloy or spoke nipples in loose fittings. It could be the wheel was just made of a bad batch of alloy or the temperatures were not right at manufacturing.

Don't wait for a catastrophic failure. There could be a defect in that wheel you won't see till its too late...

Dholton3

RD pulley cage actually does look slightly bent upon closer look, however wouldn't that cause the drivetrain to be noisy when my other wheel is installed as well? The cage is equally "bent" with both wheels installed; is there the possibility that the RD pulley cage could be aligned/running smooth with one wheel installed, but misaligned with my Roval wheel installed? AFAIK both wheels are 142x12 QR rear axles, same length and everything.

Dholton3

Well, tweaked the pulley cage slightly, it is marginally, and I mean, marginally straighter, pulley wheels seem to line up perfectly underneath cogs, same noise as before...

Crankycrank

True that most likely not the issue but I've learned to never assume anything with these confounding problems. Anyways it looks like you've taken care of that and at least eliminated a bent cage as a problem and narrowed it down to different wheels.

masi61

Could your chain be too long? If so, when in the small chainring the smaller cassette cogs would be making the derailleur pulleys try to wrap up the excess chain which a short cage RD might not be able to do thanks to an extra link or two in the chain. Does the noise in the small cogs persist when you are in the big chainring?

Another chain related possibility is that you routed the chain through the pulleys improperly. You would most likely get a God awful clattering noise if the chain is riding outside and on top of that little metal tab on the derailleur pulley cage. You and your LBS mechanic could not possibly have overlooked that, right?

nathand

Careful inspection: take the wheel off the bike, take the cassette off the wheel, look carefully for any cracks where the spokes go through or into the hub flange. Check the spoke holes in the rims while you're at it.

oldukbkr 

It sounds like the wheel (and therefore the cassette) is somehow out of alignment within the frame. Perhaps a bent axle? Or, as someone else mentioned perhaps you have a crack in flange, rim or axle that is allowing the wheel to flex. If it was OK when your mechanic aligned the derailleur hanger and then the noise came back after you rode around a bit, that suggests the wheel shifted out of alignment when you rode it. It might be worth having him check the derailleur alignment again to see if that's the case. It would also make sense the noise is louder in the high gears because an alignment problem will be more noticeable when the chain line is at a greater angle.

ShannonM

I'm thinking bent axle? Or maybe worn-out pawls or drive ring inside the freehub? Broken pawl spring? Dunno, but seems internal to the hub...

--Shannon

Dholton3

All good thoughts, thanks everyone for the feedback! Update: I was messing around with the bike a little more today during my lunch break, and just for the hell of it (and cuz I couldn't think of anything else intrinsic to the wheel that I can get at), I went ahead and recentered my rear disc brake pads. Somehow, the noise actually did go down a bit. I went on a ride after work and the noise is definitely still there, but it's not as loud as it has been the past week or so. Now I'm completely spitballing here, but could it be that in recentering the pads, the rotor is sitting in between the pads in a slightly different position, therefore making the rear wheel as a whole sit in a different position in the dropouts, changing the chainline? Because somehow in recentering the brake pads, the noise has gone down; not eliminated, but has decreased.

I do agree with you guys in that I think the wheel in general is somehow out of alignment with the frame. Because when I put in my other spare wheel, the noise disappears. The noise is definitely tied to the wheel (I'm 99% sure). Regarding your commen oldukbkr, when the first LBS adjusted the RD hanger, the noise was still there afterwards. Adjusting the RD hanger had no impact on the noise. In response to your comment, how would I be able to 'diagnose' a bent axle; would that involve taking off the freehub and removing the axle from the hub and measuring it somehow? Is there a tool for measuring if a rear axle is straight vs. bent?

CliffordK

I assume you checked the pads when you were working on them. Could the pads be worn out?

Dholton3

No, swapped out both front and rear with new resin Shimano pads about a month or two ago. So not new new, but not worn I would say; plenty of material left on both sets. BTW, for some reason Bikeforums is only letting me type 5 messages every 24 hours, so apologies if I don't reply for another day or so haha. All the advice is seriously appreciated, thanks all! The fact this has stumped me (which is unsurprising), as well as 2 LBSs, leads me to believe this is a pretty uncommon/hidden issue (at least something that wouldn't appear to the naked eye, such as a bent axle).

bitpuddle

Sounds like you have a bad freehub. Either a bad bearing or there is some play between the freehub and hub shell. I’d replace the whole freehub.

Dholton3

Could be the freehub, for sure. The last LBS I took the bike too, they said the freehub bearings felt great, they repacked everything with extra grease, and the noise still persisted. Could it possible be a smaller issue with the bearings (as you mentioned) that they can't see since they're sealed cartridge? Even if things feel great, maybe they aren't great, I don't know...

Also on a separate note, I was thinking more about whether the wheel itself has a bent axle, but wouldn't logic dictate that if the axle was bent, I wouldn't be able to fit my QR skewer through it? QR Skewer is completely straight, so if the axle was bent, I would expect that the skewer would be bent too, right? Just trying to logic my way out of having to disassemble the whole rear wheel haha...