# Rumble In Drive Train



## gofast2wheeler (Oct 13, 2011)

Okay, here is a problem that seems to have no answer. After looking at various posts it seems the answer is live with it or replace bike, never found a post about rumble,vibration in crank that had a solution. 

Here's my problem: 

When pedaling bike at 17mph I get a rumble thru the crank arms but can pedal thru it where it goes away. Does not do it before 17mph or after. Things I tried: switched to small ring and different gear in back same problem, had a worn chain so replaced it as well as cassette, was doing it before and after, replaced pedals because my last set were broken same problem, removed BB and is fine. Also took rear axle off and regreased. 

Does not do it while not on bike and turning crank fast. It seems the more force applied to pedals I can get it to do it, so 17mph seems like the force needed to recreate rumble. If there is a strong head wind rumble will appear even if speed is not 17mph (force to pedals related). One more thing I did have 2 accidents on bike nothing severe and beleive it or not no frame damage just rims which were replaced. Possible rear chain stays are bent or BB cage and if so can they be checked for alignment. (also can't remember if the bike has always had problem has been 8 years until this summer when I last rode it.)

Could the problem be related to the rear wheel that needs to be trued. My idea is when applying force it's causing the wheel to deform and the rumble transmits to crank. The back tire does sway when spinning it and does have a bent spoke (where spoke comes out of hub flange not straight installed at LBS that way not accident related). Or is this something that needs to be lived with. Mileage on bike about 4,000 miles estimate.: Colnago Master Extra-Light with campy 9spd Chorus with Mavic CXP 33 rims and Chorus hubs (bike 11 years old kept in room) Any advice would be great.


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## Hanks (Sep 30, 2011)

*Just Guessing ???*

Have you been able to duplicate the rumble when the bike is on a bike stand (I'm guessing not).

You say you removed the BB and that it is fine. What type of BB is it? I'm thinking bottom bracket. Replace/Upgrade it seems a cheap way to "eliminate" the BB as the culprit.

Switch rear wheels? (I don't discount your theory even though the 17mph has a slight "Twilight Zone" feeling to it. 

?

Hank :aureola:


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## gofast2wheeler (Oct 13, 2011)

Hanks I did swap out BB, still same thing. Trying to find another rear wheel without spending money. That 17mph is strange but it seems to be more related to force generated at pedals where at 17mph equals force that porduces rumble. Strong head wind at 14mph can also produce rumble. Driving me nuts. I would expect this on a bike from Toys-R-US but not one with prem. frame,parts, etc. Very frustrating. Will keep undated as I move along the trouble shooting procedure.


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## nightfend (Mar 15, 2009)

Are you sure it is not one of the pedal spindles grinding away?


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## gofast2wheeler (Oct 13, 2011)

Brand new pedals, shimano dual purpose pedals.


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## baker921 (Jul 20, 2007)

Does noise change/disappear as speed continues to increase? What's it like at 25mph? Have you got a big hill near you? Can you free wheel down it at 30mph? Can you get someone else to ride the bike? How do they perceive the symptoms?
Noises/vibrations are frequently most difficult to identify when they have 2 or more sources. They can have a multiplier effect at some frequencies and cancel each other out at others. 
Good luck.


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## FBinNY (Jan 24, 2009)

The key thing to look at (listen to) when dealing with any noise is the frequency and pitch. The various causes each have their characteristic frequency, most of which also vary with speed. 

Hint, the rear wheel turns 3-4 times faster than the crank, the sound of a chain on sprockets is a much higher frequency, roughly 12-24 times the frequency of the wheel rpm (depends on the rear sprocket # of teeth). Also bearing noise is unique and has it's own sound, though you rarely hear bad bearings while riding except in the most extreme cases.

I suspect, what you're hearing is the fairly normal sound of a chain coming off a sprocket, or possibly rolling over the RD pulleys. Before going crazy I'd try a decent chain oil (consider the source, that's what I sell). 

A good oil will do wonders to quiet drive train noise, and is the least expensive way to know if it's chain/sprocket related or not. Even if it doesn't eliminate the rumble, it might alter it, confirming that it's chain related, or not change anything at all confirming that it's not.


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## Surestick Malone (Jan 11, 2003)

Is this rumble a noise or a feeling? 
I can generally feel a faint vibration through the pedals on the down stroke when grinding a hard gear that I've always attributed to friction in the chain. 
I can feel it on all my bikes, some chain lubes seem to lessen it but it's always there. It's more noticeable if the chain needs re-lubing. 
Down-shifting and concentrating on a smooth spin also seem to make it go away.


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## gofast2wheeler (Oct 13, 2011)

A feeling in the pedals. When I press really hard on crank you can feel it, pedaling leisurely no feeling, but with head wind creating strong resistance rumble in crank arms appears as well as at 17 mph. doesn't make since would bike not make these rumbles when you test ride them at bike store.I use phil wood chain oil, good stuff. My idea is it is coming from crank area, no way that rumble can make its way from rear der. with out some feeling in seat. To me it sounds like whole BB and BB cage are distorting and causing bearings in BB to vibrate. Clueless right now. Probably be run over satring at my chain while trying to create vibration. I do agree with both FBinNY and Surestick Malone about chain making noise/vibratio also.


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## Kontact (Apr 1, 2011)

Most "rumbles" are when the upper jockey pulley is too close to the cassette. Something to check.


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## gofast2wheeler (Oct 13, 2011)

Kontact, rear der. Upper pulley is fine checked it. Going to check my chain line, dont know if that would cause vibration, but worth a check, doesn't cost anything to do.


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## gofast2wheeler (Oct 13, 2011)

One other thing, when turning crank chain does move left and right, sways. I never heard of front chainring being not perfectly straight. Thought it only did it while pedaling but not so. I'm thinking it is chain vibration harmonics.


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## gofast2wheeler (Oct 13, 2011)

Pretty much checked everything, so took it to LBS and they will look at it. Should have by Saturday or Sunday. While I was there took C50 Colnago for a ride to see if it did it also. Bike had campy record on it. It did do it also. When I got back told sales guy and he explained to me this was normal for the gear combo I was using. Bing ring plus 4 from the smallest cog. He said using those gears and only going 17 mph will cause that rumble noise because there is to much tension on chain and with chain being metal and sproket alum I'm mashing the gears with chain. Does this make sense to anyone, i think it does.


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## j.o.e.l (Oct 7, 2009)

I had drivetrain "rumble" (may not be the same rumble as you're experiencing) and finally traced it to worn chain. Rumble was worse when I get closer to 20 mph. Replaced chain, "rumble" gone.


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## Unknown Arch (Aug 17, 2011)

Just dealt with something similar for several weeks on my Cannondale SuperSix with a BB30 bottom bracket. After lots of iterative troubleshooting, replacing the BB bearings and slapping a new chain on it fixed the problem. Tough to say for certain which fixed the problem, but that was the second chain replacement in the troubleshooting process, and I'm thinking it's unlikely I had two bad chains in a row, so it probably was the BB.


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## gofast2wheeler (Oct 13, 2011)

chain already replaced, BB as well.


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## andulong (Nov 23, 2006)

It is a phenomenon, much like the dreaded "death wobble" and cannot be explained. Ride faster or slower or in a different gear combination.


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## gofast2wheeler (Oct 13, 2011)

andulong, I agree with you does not seem to have a explanation to it. I probably will ride faster or in a different gear. Guy at LBS did make sense about pedaling to slow in the gear I was using and causing friction between chain and front ring.


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## gofast2wheeler (Oct 13, 2011)

Okay heres the verdict. I took rear derailluer off and ran single speed with bing ring and 15 in back still got noise, rumble. So, the rear derailleur was not the issue. The last thing to check is the wheel and hub, freewheel hub assembly, but whole wheel needed. So, I went to local bike store and took a Trek 5.6 (can't remember model but was carbon) with Ultegra comp. Believe it or not I got that bike to do it as well. When pedaling in bing ring and fourth spocket from smallest at top speed I got the same rumble. So, my conclusion is the it is the rear bearings spinning out, meaning being reved to max. My hub on my Colnago has ball bearings adjustable and when pedaling looking at hub it flexes almost bends forward while pedaling. You can actually see this happen. So, my thinkng is when the hub bends the balls start to make noise because there loosing contact on races or pushing harder on races due to flex. totallly makes since to me. Probably stronger rear wheel with ceramic catridge bearings and better hub would be less flexing (stronger axle).Yes my rear hub has been taken apart and inspected and greased. Never seen any thing flex like that. It almost looks as though axle is coming foward, wicked flex.


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## bike981 (Sep 14, 2010)

It seems odd that several different bikes, some completely new if I understand correctly, would all make the rumble.

Are you *sure* the rumble really is from the bike? For instance, I recently got some new tights. First ride with them, as soon as I started going maybe 25mph down a hill I heard a sound that I thought was from my BB or cranks. Freaked me out. Turns out it was the fabric near the ankles of the tights vibrating in the wind. 25mph was the key speed to make the fabric vibrate. Maybe something similar is going on in your case -- i.e., rumble is related to *you* and not to the bike?


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## SilverStar (Jan 21, 2008)

Hub flex? Really? I find that incredibly hard to believe. Must have been an optical illusion. Hub axles, even on cheaper hubs, are incredibly resistant to flex as they are supported in two or three places by bearings. Also, ceramic bearings won't have any effect on strength/flex reduction/improved functionality. They exist solely to lighten your wallet.


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## PlatyPius (Feb 1, 2009)

bike981 said:


> It seems odd that several different bikes, some completely new if I understand correctly, would all make the rumble.
> 
> Are you *sure* the rumble really is from the bike? For instance, I recently got some new tights. First ride with them, as soon as I started going maybe 25mph down a hill I heard a sound that I thought was from my BB or cranks. Freaked me out. Turns out it was the fabric near the ankles of the tights vibrating in the wind. 25mph was the key speed to make the fabric vibrate. Maybe something similar is going on in your case -- i.e., rumble is related to *you* and not to the bike?



It's normal. All bikes do it. Even new ones. I can feel it when running through the gears on the stand.


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## donki (Nov 13, 2011)

i once had a problem with wheel bearings that created a rumble and had to get them replaced. maybe check that out??


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## hambike (Sep 3, 2005)

I've noticed a similar rumbling only in a few of my favorite gears and only when riding on the rollers. It seems to boil down to the cassette. New chain, new chainrings, new DA cassette gave me the rumble. Switched to another new DA cassette and it was quiet. Switched to a new Ultegra cassette and I got the rumble. All three cassettes were the same ratio and similarly installed. Seems like the natural gear tolerances involved are sufficient to sometimes induce a natural vibration that gets amplified through the various resonances of the other parts. Totally hit or miss in my opinion.


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## theruck (Sep 12, 2013)

i know it is an old thread but i experience the same rumble on my brand new Bianchi Via nirone 7 with Veloce 10s groupset. it drives me nuts. i tried my friends merida with SRAM Red and allthough i coukld feel the rumble when twisting the crank with hands, there was no rumble while pedaling on it. i could minimise the rumble for some gears by setting the rear deraileur to more tight chain setup but is is not completely cured yet. it drives me nuts and i can not find a solution by changing settings nor by searching on the internet. maybe i will have to get used to it? i would like to not to


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