# Rubbing/scraping noise, not the brakes



## BestSanchez (Apr 29, 2012)

I've had my GT Avalanche 2.0 for about a week now and I think the brakes are finally adjusted (they don't make any noise when I spin the wheels) so they should be fine. But when I sit ON my bike and ride it there is something metal rubbing rhythmically that almost sounds like brake rub. If I get off and pedal with my hands it goes away though, so maybe weight related? And I can't pinpoint it exactly because it only happens when i'm on it. So maybe point out some common rubbing culprits?


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## vk45de (Feb 1, 2009)

The brake lol. 


Now that I've sounded like an ass - your frame might be flexing so what didn't rub before you sit on it now does. What to do is ride around shifting your weight left to right and see if it's worse on either side.


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## joeinchi (Jun 19, 2010)

Tire against front derailleur. If you switched to a wider tire, lowered air pressure or installed the rear wheel a little off center, that might be the source.


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## CSC (May 23, 2011)

Frame flex is a good idea. What type of brakes do you have? Does the sound form whenever you are pedaling, or does it happen when you are coasting, too? Also, Run your fingers over the spokes, and make sure there is not a broken or loose one. 

A less-likely scenario is that one of your hubs is shot. Again, not likely, but not impossible, and it would explain why you only hear it when you are on the bike.


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## CSC (May 23, 2011)

also, are your quick-releases tight enough? LBS once left my front wheel too loose...made a bad sound, and almost came off on me, too


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## BestSanchez (Apr 29, 2012)

I have tektro novelas(go away if you want to hate on them, they work fine once dialed) and yeah it's not them, and I think it happens when I coast too. And where should I look if frame flex is the culprit?


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## the-one1 (Aug 2, 2008)

Flip the bike upside down. 
Spin the front wheel. Is the noise there?
If no, spin the rear wheel. Is the noise there?
If no, spin the cranks. Is the noise there?


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## CSC (May 23, 2011)

To check for frame flexation issues...I'd say you need someone of similar size/weight to sit on the bike, and you can visually inspect the breaks and other flex-sensitive parts. Puting the bike in a stationary stand might also help.
If you are getting the sound when you are coasting, and you have the shop-installed reflectors on your wheels, make sure they are not sliding around on the spokes (causes a pinging sound). Other than that, again, check to make sure the wheels are seated correctly (QR axles are resting in the frame/fork). If that's not an issue, then it's possible that the free-rotating "gear" in your rear hub (clicks when you are coasting, locks when you are pedaling) may have an issue, or, worst-case, either of your hubs has grit or a bad bearing inside. Your LBS can help if you give them an example of the sound (ride the bike in the parking lot, or tell them to)


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## BestSanchez (Apr 29, 2012)

Actually it's only when I pedal and I think I've narrowed it down to the crank/drivetrain area. I just don't visually see anything rubbing...


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## CSC (May 23, 2011)

Well...now I'd say it's a loose bottom bracket. While they are not "supposed" to work loose, they can. If you got your bike brand-new, take it back to the shop, and they should tighten it up for free. Might be the pedals. Check to see if it's your shoe rubbing the crank arm (metal bits on a pair of hiking boots can be annoying)


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## CSC (May 23, 2011)

you can check the bottom bracket by wiggling the crank arm side to side (not front to back, haha). if it feels like there's a bit of play, then that's probably it.


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## BestSanchez (Apr 29, 2012)

I actually did swap out the stock plastic flats for some old diamondback metal flats, they're banged up and dirty but I don't see how they can cause any noise.


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## CSC (May 23, 2011)

I had an old pair of pedals that had sandy grit inside, and they were pretty cranky. You could always put the stock pedals back on, just to make sure. 

I'd check your bottom bracket (component that connects crank arms to frame). It seems to be the most-likely thing causing you trouble.


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## xenon (Apr 16, 2007)

If there is noise only in some gear combinations, it may be the chain rub against the FD. If it is the case, adjusting the FD should solve the problem.


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## James_spec (Jul 28, 2011)

xenon said:


> If there is noise only in some gear combinations, it may be the chain rub against the FD. If it is the case, adjusting the FD should solve the problem.


^^ More than likely what he said. If you hear rubbing only when you pedel, it's your chain hitting the front deraillleur.


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## CSC (May 23, 2011)

James_spec said:


> ^^ More than likely what he said. If you hear rubbing only when you pedel, it's your chain hitting the front deraillleur.


His OP states that if he gets off the bike and pedals, the sound is not produced.
Could be chain rub, but I'd think that would be pretty easy to spot.


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## joeinchi (Jun 19, 2010)

Is it a *whir, whir, whir* sound? Like the sound of soft knobbies being pedaled on pavement?


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## Abe Froman (Jan 12, 2011)

Nm....


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## BestSanchez (Apr 29, 2012)

A lot of these sound plausible haha, and it's there when I coast too(my bad) so it's not the pedals(or FD?)...


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## BestSanchez (Apr 29, 2012)

Alright bringing this back up because I had gotten used to it after a while and wrote it off as normal, but today I noticed it's making a loud squeaking sound(not high-pitched) now too. I've gotten much closer now though because I noticed it's 100% weight-influenced. If I lean over my handlebars it disappears, yet if I lean far back over my rear wheel it gets really loud. Any thoughts? Sounds like something needs lube.


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## huffster (Nov 14, 2011)

You say you've had the bike for a week now. This may be an assumption, but if you bought it new, take it to the bike shop and make them figure it out.


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## huffster (Nov 14, 2011)

OK, now lets assume its not new from an LBS...

Here is how I might eliminate the brakes for sure. I would pull the rear brake caliper and wire-tie it to the frame somehow with a wedge between the pads to keep it from compressing. In other words, ride without a rear brake. Repeat for front. If you can ride a wheelie, it might be interesting to know if it still happens. At least that would eliminate the front-end.


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## BestSanchez (Apr 29, 2012)

Yeah it was new but the shop is pretty far and i'm too lazy haha, so i'm trying to figure this out like a man. And yeah I tested it with no brakes and it's still there. Since it's only when I sit and amplified when I put my weight back, could it be a hub? I know nothing about wheel hubs.


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## joeinchi (Jun 19, 2010)

Hmmm ... could be a hub. If possible, can you swap the rear wheel? Perhaps borrow a friends to make sure your wheel is the source of the noise.

But, yes, sound may be coming from the hub. If the bearings are loose, need lube or worn ... sure, it could make some odd noises. You might need certain tools to sort it out but it's nothing too complicated.

Video at the bottom of the page give you a quick overview: How to Grease Bicycle Wheel Bearings with Step-by-Step Pictures


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## Skrufryder (Aug 13, 2011)

Yeah it sounds like a rear hub to me. Lack of lubercation I would suspect. I know It was bought new from LBS. They just take it out of a box and put the wheels on. I do know that the joytech hubs are not sealed bearings, and the grease they use in the bearings isnt that highgrade. i know that aluminum just amplifies the heck out of that sound!


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## CSC (May 23, 2011)

Wow...I bet that's what it is. I did not know anyone still made open/ un-sealed hubs.

That will be fun when if you ride on sand or through a creek.


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## Winsecure (May 1, 2012)

May want to take the seat post out and put some lube on that to rule that out. I fought a creaking//squeaking seat post issue for weeks before I tried that.


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## Kcebrah23 (Apr 5, 2012)

are you in between gears?


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## xenon (Apr 16, 2007)

CSC said:


> I did not know anyone still made open/ un-sealed hubs.


Only small little known manufacturers like Shimano still do.
BTW, I had squeaking noise from a brand new sealed rear hub - replacing the bearings under warranty solved the issue.


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## CSC (May 23, 2011)

xenon said:


> Only small little known manufacturers like Shimano still do.


Looked at their lineup, and all of their mountain bike hubs are sealed. Even the "bottom" level Alivio hubs.

I understand for road use that they may be open: saves weight. But unless the bike came with cheap hubs (which would surprise me)...they should be sealed, or have a rubber gasket to prevent grit from getting in there. Even though it still can sometimes.

If you have spent more than a few hundred dollars on the bike, chances are it has sealed hubs...especially for a mountain bike.
I bet the shop accidentally got some grit in there when they assembled the bike.
Or, as you said, the bearings are faulty. Either way, the shop will deal with it.


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## joeinchi (Jun 19, 2010)

CSC said:


> Looked at their lineup, and all mountain bike hubs are sealed. Even the "bottom" level Alivio hubs.


I beieve you gents are talking about two different things (sealed hub vs sealed bearings) and both correct.

Sealed bearings are typically found in headsets and other applications and look like this:









Typical hub assembly:


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## CSC (May 23, 2011)

so #12 and #15 would be the bearing rings...and I can see how those could be open. But from my research, the hub assembly as a whole should be sealed for most decent bikes (few hundred dollars and up, price-wise).


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## joeinchi (Jun 19, 2010)

CSC said:


> so #12 and #15 would be the bearing rings...


Technically, the rings that glide along the bearings are races.

Hubs are assembled with just a tiny bit of play to allow for unencumbered motion, so they are not completely dustproof. Too tight and your wheels don't spin freely--too loose and you get contaminants.


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## prepsheriff (May 8, 2012)

I'm getting the same symptoms on my "03 Hardrock. Up of the saddle, light thumping sound goes away, back in the saddle, light thumping comes back. Does sound like it's coming from the rear hub, also seems to tempo on a full wheel rotation.


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## CSC (May 23, 2011)

prepsheriff said:


> I'm getting the same symptoms on my "03 Hardrock. Up of the saddle, light thumping sound goes away, back in the saddle, light thumping comes back. Does sound like it's coming from the rear hub, also seems to tempo on a full wheel rotation.


Check your bottom bracket (wiggle the crank arms side-to-side...if they feel loose, that's probably your issue)...chronic issue with the stock bracket (can feel like there's something "skipping" or sometimes "banging" in the drive-train). The reason it may go away when you stand on the pedals is the increased tension you put on the system while standing, which holds the bottom bracket in place.

Unless it is from your rear hub, then get LBS to check that one out.

Both wore out on me after 6 years of hard use (as a kid)...and yours is an older bike than my old one (an '05 Hardrock).

Check both of these.


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## BestSanchez (Apr 29, 2012)

Went away after I adjusted rear brake(it was squealing), even though I completely ruled out the brakes a while back :skep: then again the noise did sound just like brake rub.......


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## sonics60 (Apr 12, 2015)

Hi, 

I appreciate this is an old thread, but if anyone is still listening, I was wondering if a solution was found?
I'm having the same issue with a brand new Scott aspect 740. It's been back to the shop several times and they are claiming they can't hear anything and the bike is fine. I obviously disagree because the noise is obvious. It's hard to tell where the noise is coming from when riding, but I'm sure it's from the crank or bottom bracket area. It only happens with weight on the bike and is noticeable when peddling and free wheeling. Any advice will be much appreciated.


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## sonics60 (Apr 12, 2015)

Apologies, I'm reading on my phone and just noticed further comments highlighting it's been resolved.


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