Ungodly metallic crunching noise coming from cassette/chain
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Ungodly metallic crunching noise coming from cassette/chain
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:
Some final things:
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:
- 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.
- 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.
Some final things:
- 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.
- 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).
- 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).
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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.
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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?
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?
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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...
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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...
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.
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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.
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.
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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.
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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?
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?
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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?
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?
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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.
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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...
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...
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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.
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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...
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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.
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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?
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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.
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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.
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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...
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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?
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?
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I assume you checked the pads when you were working on them. Could the pads be worn out?
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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).
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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.
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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...
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...