# How to eliminate resonant frequency in AL frame? Expanding foam? Lead weights?



## EPeff (Apr 2, 2009)

Hello everyone,

I was directed to this section of the forums after having no luck in the Brake forum or Specialized forum, and I'm looking for a frame building super guru wiseman or wisewoman who may be able to guide me (and many others) on the path of a quiet ride.

I'll keep the issue somewhat short and simple... (there are 150+ posts on this in the Specialized forum, so I am paraphrasing quite a bit)
All 2009/2010 Specialized Stumpjumpers affixed with hydraulic brakes (Avid Elixir standard) create a resonant frequency in the rear stays that transfers into the whole frame, causing vibration and a loud loud annoying howling noise from the rear brake. Specialized points the finger at Avid, Avid has been trying to come up with fixes, but it isn't the Avid brakes, it is the frame. This is proven because different makes/models of brakes have been tried, and they all do the same thing.
Here are some of the non-working fixes so far.....
-New solid non-vented G3 rotor from Avid (noise/vibration then came back)
-Switch from metallic to organic pad (noise/vibration then came back)
-Switch from organic to new metallic pads (noise/vibration then came back)
-Switch from new metallic pads to new organic pads (noise/vibration then came back)
-New vented G2 rotor from Avid (noise/vibration then came back)
-New, different brand rotor, any make/model at all (noise/vibration then came back)
-Upgrade from Elixir R to Elixir CR (noise/vibration then came back)
-Adjusting, truing, cleaning, balancing, reinstalling, checking, adjusting (noise/vibration then came back)
-9 trips to the LBS (noise/vibration then came back)
-New Shimano brake adapter (noise/vibration then came back)
-One user installed Formula RX brakes (noise/vibration then came back)
-One user suggests spraying expanding foam into the rear stays (not tested yet)
-One user wrapped the opposite chainstay in innertube (noise/vibration is muffled)
-One user ziptied lead fishing weights onto the rear brake caliper (noise/vibration is 90% eliminated)

Alright, so other than those last two fixes, another real fix doesn't exist. Avid has put together at least 4 different "fix kit packages" to send to the LBS, and they never work. Any amount of tweaking with the brakes themselves is useless. It is the combo is hydraulic brakes with this frame.

So why I'm here... I want to run two ideas by some of you who know materials and perhaps even a bit about vibration dampening.

1) Spraying the frame's rear stays with expanding foam (Great Stuff) - it will probably void the warranty, which sucks. Will this help? Could the expanding foam expand so rapidly that is cracks a stay?

2) Using Ti bolts for the rear brake caliper and caliper mount. My thought is that the different density/mass of Ti might not transfer this frequency into the frame, or at least deaden it a bit. Obviously aluminum fasteners are not an option here. I was also thinking about some other type of material to use for the washer for the caliper adapter. Similar to phenolic material used for car intake manifolds to prevent the cylinder head from transferring heat to the intake manifold... maybe there is a specific material washer that would help eliminate the transfer of vibration into the frame?

and

3) Do you have any other suggestions of how to eliminate this issue (without adding weight via inner tube or lead weights to the bike). These 09/10 Stumpjumpers may not be the nicest bikes in the entire world, but there are many owners like me, who had a budget, and bought the best bike they could afford. Putting lead fishing weights on a $2k bike is just ridiculous. Its not a fix, its a lead band aid.

Many people are dealing with this issue, and there no fix is in sight from Spec or Avid, so your help would be greatly appreciated!

Thank you and take care


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## mikael_nr1 (Dec 17, 2005)

Sure the caliper mounts on the frame are not out of alignment?


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## crux (Jan 10, 2004)

This is a fun one. I had this happen to a guy and nothing would cure the issues. THe vibration was so bad you could feel it in the seat. It was a FS bike and even after facing the tabs the vib remained. New brakes same model were tried and vib. remained. Went thru quite a few different attempts. What finally fixed it was getting a different brake adapter. Think we put on a Formula one and it went away. Prior to that we did a shimano, hope and Magura Adapter and the noise & vibration remained. 

This will be annoying, but swap out one component at a time till the noise is gone.

I'd also check the frame for potential cracks in the area. However small that could be a potential source, but unlikely.


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## jay_ntwr (Feb 15, 2008)

I'm assuming all these trials are with 160mm rotors too huh? Have you tried either a 180mm or a 140mm?


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## RoyDean (Jul 2, 2007)

try changing brake disc diameter?


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## RoyDean (Jul 2, 2007)

Got me by a minute, jay...


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## Walt (Jan 23, 2004)

*Lots of bikes do this with Avids*

I know for a fact that Turners and Ventanas have this problem with several models of Avid brake. There is a HUGE thread about Avid brake squeal floating around somewhere...

I will join in with the rest of the replies - swap out brake parts until it goes away. I don't think frame mods will help.

-Walt


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## Guitar Ted (Jan 14, 2004)

We had a similar issue while testing a Giant XTC 1 29"er. Hydro-formed frame, Avid brakes. A lead fishing weight killed the noise. We felt it was due to the tabs on the frame to mount the adapter that were too thin, allowing for a vibration. 

Eventually we switched out to a new set of brakes and as far as I know, that cleared up the problem. (I do not have the bike here now to verify this)


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## shirk (Mar 24, 2004)

Norco had a very similar issue with either the Fluid or the Fluid LT. They ended up changing the seat stay and adding a small gusset and it fixed the issue. I'll have to dig around NSMB to find the details.


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## unterhausen (Sep 28, 2008)

I propose connecting the NDS seat stay to the NDS chain stay with two hose clamps and a spoke


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## shovelon (Mar 16, 2006)

Had the same problem with my Serotta softail. Hayes hydrualic 22mm mounts.

Switched to organic pads, was better but progressively got worse. Out of frustration, I soaked pads in White Lightning. No power but no niose. Eventually came back. 

Friend gave me some Stans alum rotors. Put them on, lubed pads with white lightning to break in the rotors, and problem solved. Power is decent too.

I think the alum rotor dampens the vibration.


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## customfab (Jun 8, 2008)

I'd be willing to throw some great stuff in their. I did it with an aluminum bar once and it was noticeable. I don't know why it would void your warranty either, not like you modified the structure of the frame. Dynamat may be another option. Might go down to a car audio shop and see if they can give you some scraps to play with.


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## EPeff (Apr 2, 2009)

I should have come here first all along. Some great suggestions.

One of the suggestions from the other thread was the new Shimano brake adapter... but I didn't think about using other brands as well (Hope, Magura, Formula, etc). Again, following the idea of different mass/density/shape material between the frame and brake to help deaden the vibration.

Here is my next steps; (each step following the next if that previous step doesn't work)

Shimano brake adapter which arrives in 2 days...
then Hope, then Magura, then Formula adapters...
Dynamat (a little price the same shape as one side of the brake adapter - aka; Clean)
180mm front and back rotors... (potentially 2-piece)
great stuff expanding foam in the rear stays...

Thanks again everyone, you have been a great help.r


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## bobbotron (Nov 28, 2007)

*Great stuff*

If you do go the Great Stuff route, you should practice using it on something you don't care about first, like filling a small diameter pluming tube or something. The directions say something like "don't fill the void over half full" - they mean it! It is a great product, but it really does expand. I think a lot of people who use that stuff over fill the first time, and either have something pushed out of the way, or have to cut off a huge expanded blorb of GS after the fact. Or both! A little goes a long way.


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## SC RockLobster (Jul 22, 2007)

*throwing it out there*

what about a carbon brake adapter. carbon should be great for this app.


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## EPeff (Apr 2, 2009)

SC RockLobster said:


> what about a carbon brake adapter. carbon should be great for this app.


I have no knowledge of carbon brake adapters. Is this a joke, or is this even real?

I'm weary of using any carbon on my bike (heard too many stories, I'm a clyde, just my choice I guess...) but I wouldn't be adverse to this if it were actually a real product and has a proven track record.

Maybe even a Ti adapter?

Anyone know if either of these exist?

Google searching came up fruitless.

Thanks much


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## giantbikeboy (Dec 3, 2004)

Had the same problem with my Blur and the Juicy Sevens. Tried everything and nothing stopped the howling. Put some new XTs on it and problem solved. Put the Sevens on my 575 and they are quiet as can be. Brake/frame combo?


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## Megashnauzer (Nov 2, 2005)

there was some stuff made by loktite that went on automobile disk brake pads to stop squealing. i bought it years ago for that problem with a honda i had. anyway i had howling from a set of avid brakes that wouldn't go away. i put this stuff between the rotor and the hub before i bolted it on. i also put it on the back of the pads before inserting them in the caliper. it didn't make the problem go away entirely but it knocked it back quite a bit. the stuff is like orange silicon. it's cheap and might be worth a try.


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## EPeff (Apr 2, 2009)

giantbikeboy said:


> Brake/frame combo?


Exactly.

Unfortunately with my specific frame it seems most brands/makes/models will cause the same issue.

So did I get fooled into thinking carbon/Ti disc brake adapters are real? Doesn't seem logical for CF, but maybe Ti.

Thanks for your responses.


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## Francis Buxton (Apr 2, 2004)

I would seriously try a little strip of Dynamat. Its entire purpose is to reduce vibration resonance. It did a great job in the trunk of my 72 Nova with a 12" sub when I was in high school.


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## wv_bob (Sep 12, 2005)

bobbotron said:


> If you do go the Great Stuff route, you should practice using it on something you don't care about first


And wear gloves unless you think it'd be cool to carry the stuff around with you on your hands until it eventually wears off.


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## EPeff (Apr 2, 2009)

Francis Buxton said:


> I would seriously try a little strip of Dynamat. Its entire purpose is to reduce vibration resonance. It did a great job in the trunk of my 72 Nova with a 12" sub when I was in high school.


I'm going for it.

Got my new Elixir CRs on there now, upgraded for free from the Elixir Rs under warranty.

I can hear the vibration coming back after a couple of days already.

I'm going to get the Shimano adapter (still waiting), and pick up some tiny pieces of Dynamat on the way to the LBS when I pick it up, both will go on at the same time.

I totally forgot about using Dynamat back in high school as well- that stuff does its job. I'd imagine that alone will eliminate it completely.

Will report back, great suggestions all.


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## EPeff (Apr 2, 2009)

*Silence!*

Finally! After months and months of going to the LBS (11 times now total) - my Avid Elixir R/CR howling rear brake problem is GONE.

Braking firmly and silently.

I used the Shimano rear disc brake adapter and a tiny piece of Dynamat on the adapter itself. The piece of Dynamat is about 0.5" x 1.0" and placed in the center of the adapter on the side facing away from the rotor, as there isn't much room for clearance on the rotor side, otherwise I would have wrapped the whole thing.

Thanks for all your suggestions, much appreciated.


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## eMcK (Aug 22, 2007)

Hope this is the end of your problems. If it comes back, and you are using an external cam skewer, exchange it for a Shimano internal cam, doesn't matter the model. I've fixed a few noisy brakes this way.


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## jayz28 (Feb 2, 2009)

EPeff said:


> Finally! After months and months of going to the LBS (11 times now total) - my Avid Elixir R/CR howling rear brake problem is GONE.
> 
> Braking firmly and silently.
> 
> ...


Do you mind posting a photo of your fix? This may help many of us with this dreaded problem. :thumbsup:


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## EPeff (Apr 2, 2009)

Never heard of this skewer before? Care to tell?

EDIT: Just did a second of Googling to find the answer. Yep, I'm using the Shimano internal cam skewer in the back already. DT Swiss RWS up front (came on the bike). Never had an issue with a Shimano skewer of this design ever in the past, so I never found a reason to "upgrade".


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## EPeff (Apr 2, 2009)

Here is the photo of the rear disc brake adapter with a small piece of Dynamat. I had a industrial grade black permanent marker next to my work space, so I make a swipe across the silver shiny Dynamat backing, so it would disappear. 

Again, I trimmed off the Dynamat piece at the face that faces the rotor side, as the clearance is very thin back there, so I did not want to risk it catching debris.


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## customfab (Jun 8, 2008)

do I get anything for posting the winning fix? glad your noisy bike isn't noisy anymore


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## magic71 (Oct 24, 2008)

*silicone ?*

i have been using silicone, same one you would use in car breaks. One I have is super blue silicone made by VERSA CHEM it a old tube and I'm not sure if in production, but there's got to be others too
and I apply it to back side of pads before they get installed that it !


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## Marc Hanses (Jul 29, 2009)

Well I would love to help you , but there seems to be a fine line as to how I go about it without breaking the rules of spam on MTBR. I am the manufacture of Squeal Out Disc Brake Treatment and I would like to send you a sample of my paste to see if it will help you. I have tested it on ton's of squealing/ humming/ chattering disc brakes on bicycle and motorcycles , cars , and atv's. You apply a very small amount of the paste to the rotor and let it get between the pad's then push the bike while applying the brakes on and off for several yards, it buffs and polishes the rotor and pads to create a balanced match between the two surfaces . Then you clean up the excess with isopropyl alcohol . There are a few more simple steps to using it than that but that gives you a basic idea of how to use Squeal Out. 

It has never let me down, you will see it in bike shops very soon , we shipped off our first batch today to one of the largest Bicycle Wholesalers in the industry . However I have not tested it for a condition like yours which is a great opportunity for me and my product and a good one for you if it works . If this interests you send me your address in a private e mail and I will be happy to send you a sample. Also this goes for the rest of you in this forum , The Turkey squeal really is a major pain for us all and I just want to help out.

If anyone else want's more info I think you will have to e mail me on this site , so I don't break any rules lol. And let me be very clear so as to not offend anyone ,,, Im only trying to help you guy's and girls, that's why I will send you a FREE !!!! Sample LOL. Im not a spam guy k. Regards Marc


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## dwyooaj (Dec 14, 2006)

I've been having this squeal with avid elixirs on my new banshee rune. Got reaaly bad last week and felt it in my seat. I thought maybe my seatpost is so old and worn (from always droppingh it down/raising it) that it rattles around in the seat tube. Got a new seatpost and its better but not gone. Glad i found this thread-I'll try the dynamat next.


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## TimT (Jan 1, 2004)

Not sure how long the Dynamat will last you. I'd try a piece of Nylon. You can get Nylon washers from McMaster Carr (www.mcmaster.com) Try something thin first. I'd also try foam in the tube.

Tim


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## dwyooaj (Dec 14, 2006)

where do you put the nylon washers? cps bolts or adapter to frame bolts?either one would change position of calper... I just looked at their site and the washers for that size bolt are 1.37 mm thick,


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## TimT (Jan 1, 2004)

I'd put it in the same spot as EPeff put it . In between the frame and the adaptor. But yes 1.37mm is pretty thick . Mcmaster also has sheets of Nylon , as thin as .01" You can get some as thin/thick as your comfortable with and cut some out. 

Tim


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## wreckedrex (May 2, 2007)

magic71 said:


> i have been using silicone, same one you would use in car breaks. One I have is super blue silicone made by VERSA CHEM it a old tube and I'm not sure if in production, but there's got to be others too
> and I apply it to back side of pads before they get installed that it !


You can buy little blister packs the stuff from most any auto parts store. It's usually sitting on the counter with the dielectric grease and anti-sieze.


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## Marc Hanses (Jul 29, 2009)

Squeal out disc brake treatment for bicycles works , if anyone would like to try some let me know and I will send you a free sample . Have a great day all ! Regards Marc


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## EPeff (Apr 2, 2009)

Heya!

I'd love to give it a shot and let you know how it works out.

I'll pull the Dynamat as well

Just emailed you from my *real* email address. T****[email protected]****rW****n.com

Thanks!


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## dwyooaj (Dec 14, 2006)

update: hit the trails with the new seatpost. The squealing/vibration is greatly reduced, but still there occasionally. I think it originates at the back brake, and resonates with the frame, and also with the old worn-out seatpost/seattube interface (but at least that aprt is gone). Id like to try some of the automotive silicone-type anti-squeal that was mentioned behind the pads, but im worried about it getting into the piston seals and gunking them up, since they are smaller and closer to the caliper surface than in car brakes. Any thoughts?


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## wv_bob (Sep 12, 2005)

I tried some of that automotive anti-squeal. All I got to show for my trouble was sticking pistons.


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## dwyooaj (Dec 14, 2006)

thats what im afraid of...


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## dwyooaj (Dec 14, 2006)

Epeff, is there Dynamat acting as a washer between brake adapter and frame, or did you simply put a piece of it just on the exposed side of the adapter?



EPeff said:


> Here is the photo of the rear disc brake adapter with a small piece of Dynamat. I had a industrial grade black permanent marker next to my work space, so I make a swipe across the silver shiny Dynamat backing, so it would disappear.
> 
> Again, I trimmed off the Dynamat piece at the face that faces the rotor side, as the clearance is very thin back there, so I did not want to risk it catching debris.


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## dwyooaj (Dec 14, 2006)

Well, I put my elixirs back on. (I've been running juicy's since my last post here, absolutely silent but i thought id give the elixirs another try). My car mechanic lent me a bottle of some spray-on antisqueal rubbery coating. I coated the back of the pads, the outer side of the mounting adaptor, and the inner side of the rotor. Riding around the street the squeal was there at first (hopefully just the pads rebedding) but then it seemed to go away. I wont really know util i hit the trails and do a dh. ill post back.


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## jasman_mtber (May 1, 2009)

I have the Avid Elixir CRs on a 2009 Motobecane FS (aluminum) making this awful sound and I've been looking for something relatively easy. I've tried the obvious readjusting the calipers, wiping rotors and pads with alcohol, and sanding the pads (tried to remove the glaze, didn't angle them) - didn't help.
I noticed pressing my foot on the chainstay (caliper side) would stop the noise so I tried the inner tube wrap which worked! 

Next I will try Marc's Squeal Out since the inner tube fix is pretty lame for an XTR bike, even if it is just a Motobecane.

Jason


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## Borgschulze (Nov 5, 2007)

I had the same issue..

Banshee Wildcard with Elixir CR.

Final solution...

Took a flat file, and filed the leading and trailing edges of the pads on a 45 degree angle.

Now they only get pissy when I ride through a river.


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## customfab (Jun 8, 2008)

dwyooaj said:


> where do you put the nylon washers? cps bolts or adapter to frame bolts?either one would change position of calper... I just looked at their site and the washers for that size bolt are 1.37 mm thick,


The CPS hardware has washers about that thickness in the stack. If that's what you are going to try put them as the last thing before they bolt to the adaptor


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## dwyooaj (Dec 14, 2006)

well so far so good! dont know if its the adapetr or the rubbery stuff, but from now on im doing both. I still might keep the jucies as a backup just in case. elixirs are so much better though.


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## dwyooaj (Dec 14, 2006)

btw the spray i used is Permatex® Disc Brake Quiet


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## chewymilk99 (Nov 26, 2008)

If you have holes in your frame try the spray foam first. I can guarantee you it wont crack your frame. Its just aerosolized glue with Pollystryine mixed in. It expands but not with force. I had the same problem with my blt on the rear brakes (notice a trend?) And I used a 2mm tick pies of delran plastic (butcher block) and if made it go bye bye.


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## dwyooaj (Dec 14, 2006)

update: the shrieking came back. I then wrapped a tube around the nds seatstay, and i think that finally got it!


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## jasman_mtber (May 1, 2009)

*UPDATE: Squeal Out worked for me*

The inner tube wrap on the brake side chain stay worked under most conditions but after some dusty riding, it came back bad. Marc (PV Bikeworks) sent me a free tiny sample of Squeal Out and 5 minutes later, it made the brakes completely silent like new! It lasted about 10 dusty rides so I'm ordering a jar....I can't stand the turkey gobble and this has been the only thing to reliably stop it. Marc seems like a good guy and his stuff is definitely worth a try.
(I hope this doesn't sound like an ad; I'm just a very pleased user with no affiliation to Marc)


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## Marc Hanses (Jul 29, 2009)

Thank you jasman for the kind words. I am very happy that your squeal is gone. And thanks for taking the time to inform this forum of your results using the free sample of Squeal Out Disc Brake Treatment . Thanks again ! Marc


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## febikes (Jan 28, 2011)

One idea is to face the mounting areas for where the brake connects to the frame. Park and others make facing tools for this.


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## Coldass (Nov 23, 2005)

Ok I have something new to add...

I have found this whole issue related to vibrating caliper pads. That is one of the caliper sides to have play and to vibrate at the pad (mismatch to the other side). I have had my most frustration with Avid, once with Shimano but NEVER with Magura.


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## Mountain Cycle Shawn (Jan 19, 2004)

I would have tried a floating rotor.


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## Breezin86 (Oct 26, 2010)

What a nightmare... I'm on step one with my LBS on this issue. I have a 2011 Specialized Stumpjumper FSR Comp 29er (XXL frame) that has the vibration problem BIG time. My LBS called Avid/SRAM and they said I improperly broke in /bed in my rotors and that was causing the vibration problem. But they sent new rotors and pads to fix it. Ok fine, so the LBS got the replacement vented G2 rotors and I think organic pads put on today. They also instructed me on how to properly break them in... /sigh

Hell I hadn't gone 5 miles before the ridiculous vibration was back. It reverberates though the entire frame accompanied by a horrible sound ($89 Walmart bikes sound better). I'm embarrassed to even use my back brake when other riders are around. Haha.

I've read all the threads I could find on this topic and it seems like different things work for different people. Just not sure how much time I should waste trying to get Specialized to fix this via warranty work. I'd rather not have to throw my own money at this to get it fixed... but the more time my bike spends at the shop the less time I'm riding!

So for the hell of it I figured I'd try the tube and fishing weight thing.... so here it goes:










Fishing weight zip tied on and an old tube wrapped around the seat stay... how ghetto is that! The sad thing is it actually works and I can brake in peace with this setup. But this doesn't even come close to being a real permanent solution.

I'll be heading back to the LBS to see what they say the next step is for a reasonable solution.

I also did order some of that Squeal Out stuff in desperation... will report back my findings.


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## Mountain Cycle Shawn (Jan 19, 2004)

Try a floating rotor.


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## Breezin86 (Oct 26, 2010)

Mountain Cycle Shawn said:


> Try a floating rotor.


I will add that to my list of things to try when I give up on Specialized getting this taken care of via warranty work.

I found a number of folks that talk about Alligator Wind-Cutter rotors working well. But I'd have to see if I could get a rear brake adapter that would allow me to go from the current 185mm to 180mm for the Wind-Cutter. I'll look up some info on the floating rotor as well. Thanks for the tip!


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## dwyooaj (Dec 14, 2006)

Why is it not a real permanent solution? Its what I did on my Banshee Rune; combined with a different brand (hayes) caliper mounting bracket it was the only thing that worked. Do you just not like how it looks, or the extra weight? As long as it works who cares! 
Next step is simply different brakes that dont resonate with you're frame, I eventually ditched my Elixirs for Shimano Saints, dead quiet and I even took the innertube off.



Breezin86 said:


> Fishing weight zip tied on and an old tube wrapped around the seat stay... how ghetto is that! The sad thing is it actually works and I can brake in peace with this setup. But this doesn't even come close to being a real permanent solution.
> 
> I'll be heading back to the LBS to see what they say the next step is for a reasonable solution.
> 
> .


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## Breezin86 (Oct 26, 2010)

dwyooaj said:


> Why is it not a real permanent solution? Its what I did on my Banshee Rune; combined with a different brand (hayes) caliper mounting bracket it was the only thing that worked. Do you just not like how it looks, or the extra weight? As long as it works who cares!
> Next step is simply different brakes that dont resonate with you're frame, I eventually ditched my Elixirs for Shimano Saints, dead quiet and I even took the innertube off.


Well for me it's the principle of it... I expect a brand new bike that retails for $2,700 to at least function well in all the basic areas. I know its not as much as many of the nicer bikes out there but come on... I should be able to brake without my bike feeling like it wants to vibrate out from under me. Doesn't seem unreasonable to me 

But ya... it's also ugly as hell and adds more "unnecessary" weight.


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## Mountain Cycle Shawn (Jan 19, 2004)

Breezin86 said:


> I will add that to my list of things to try when I give up on Specialized getting this taken care of via warranty work.
> 
> I found a number of folks that talk about Alligator Wind-Cutter rotors working well. But I'd have to see if I could get a rear brake adapter that would allow me to go from the current 185mm to 180mm for the Wind-Cutter. I'll look up some info on the floating rotor as well. Thanks for the tip!


I have 2 sets of Alligator Wind Cutter rotors, 160 and 140mm and I really like them, Also, they look cool. And you can get them really cheap on Ebay.


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## dwyooaj (Dec 14, 2006)

well I can understand that. But the fact that that particular brake resonates with that particular frame is also a physical principle and the only solution is to dampen the vibration (inner tube, Dynamat) or change its frequency (lead weight or differntly shaped mounting bracket). Pretty much the only fix, unless you can get Specialized to replace with a different brand brake for free, which they should, but they wont. So you can either live with a cheap inner tube around the stay and not worry about it anymore, or keep running in circles with the lbs (they wont have a better solution than what you've already done) or spend more money on different brakes.. Have you tried a Hayes bracket, without the inner tube? What also helped me was spraying a few coats of permatex disc brake quiet: http://www.permatex.com/products/au...nce_repair/auto_Permatex_Disc_Brake_Quiet.htm on the side of the bracket where it mounts to frame, and also on the rotor (cover the braking surface when spraying!) on the side that faces the hub. DO NOT spray it on the back of the pads like it suggests for an automobile, on a mtb brake it will gum up the pistons, and it burns way from there pretty quickly anyway. The combo of hayes adapter, inner tubes on both chain- and seat-stay, and permatex is what did the trick for me, rode it like that for 6 months and forgot the tube was there, was so worth it for the silence. But last month I got saints because I was tired of the elixir's durability problems, and they run completely silent without all this mumbo jumbo, at least on my frame.


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## Adam_M (Aug 8, 2008)

I've now got this problem with my Avid juicy brakes on a Ti hardtail. Really annoying it is too. Thankfully, there are lots of good ideas listed above that I will try.


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## Breezin86 (Oct 26, 2010)

I think what bugs me the most is that this has been a known issue with the Specialized Stumpjumpers back to at least 2009. But I assume the number of affected bikes is small enough that it doesn’t justify the cost of a design or component change. Avid points their finger and blames the frame… Specialized points their finger at the brakes… and the customer ends up going in circles with the repair shop. Eventually they get frustrated and start throwing their own money at the problem while chasing possible solutions from the forum. I was pretty much ready to start doing that myself. But that really shouldn’t be the job of the consumer.

Specialized should be shipping a finished product that works and is safe. The customer service rep I spoke with didn’t like the term “unsafe” in relation to this vibration issue. He was quick to point out that the bike is safe and it’s more of an annoyance then anything else. But I’d really disagree here... now that I have my temp fix (fishing weights & tube) on I can really see how much of an affect this brake problem had on my riding. You take a steep technical section that is already sketchy and throw in some wicked vibrations from your brakes and it makes everything seem harder. Even if it’s only the perception of performance it affects the confidence you have in your equipment. With so many sports like this one you are simply doomed if you don’t trust the equipment that you use.

But back to the main issue, I do find it interesting that OP calls himself a clyde in a follow up post. I’d fall into the same category and ride on an XXL frame. I’m wondering if this issue is more pronounced with the larger frames. I’d be curious to know how many of the people with this problem are running on the XL and XXL frames. I’ve had great luck with Specialized in the past and my whole family rides their bikes. This is the first time I’ve had to test them with a customer support issue so I’m curious to see how they handle it. My LBS has a call into their rep and wants to have me bring the bike down when their store rep makes his next visit to their shop. We will see what they end up doing. I bought the bike so I could ride it... not have it tied up in the shop while they play around with fixes. That should have already been done through Specialized R&D and/or quality assurance departments.


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## Homer (Oct 2, 2004)

A slight bump, but here is my short term solution, I'll just match the total mass with dynamat instead of tubes and make it a bit more elegant.


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## Adam_M (Aug 8, 2008)

For what it's worth, I eliminated the problem by swapping the rotor for a G2 (I think - the non-wavy one, anyway) and realigning the caliper. It's been silent ever since.


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## cbchess (Dec 20, 2003)

Did anyone ever try the expanding foam inside the chainstay?


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## Homer (Oct 2, 2004)

cbchess said:


> Did anyone ever try the expanding foam inside the chainstay?


I did actually. Didn't do anything. It wasn't enough mass to be an effective mass damper unfortunately. :madman:


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## Breezin86 (Oct 26, 2010)

They ended up giving me a new frame. Problem is now gone. What a pain though.


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## ChuckChurch (Oct 4, 2005)

Hey all. Lots of good info here. Been fighting this rear braking vibration on my 2010 Trek Fuel Ex9. It's an Avid Elixir R, 185mm. Bike hasn't always done it, but it's been doing it for a couple months. Replacement brake pads haven't fixed the issue, tried both Jagwire and Koolstop. Also tried swaping my front and rear rotors, still no luck. After reading this thread, I tried a few 'counterweight' type things around the caliper adapter. No luck. Finally tried a used 160mm Hayes rotor and adapter. Braking power is diminished, but the vibration seems to be gone. Only tried it in the driveway, will know for sure after first real ride. Since this rotor is worn down a bit, started looking for a replacement. Stumbled upon this: Universal Cycles -- Avid G3 Brake Rotors Check out the description for the SolidSweep ones. Anyone tried these?


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## Broussard (Mar 17, 2005)

I struggled with this issue on my Niner One 9 for months. Swapped rotors, pads, entire caliper, etc etc and nothing worked. Terrible howling and vibration. I put weights and rubber and whatnot on the stays, but while this made it quieter, it did not stop the resonance. That's what made me realize that the resonance was not in the seatstay or chainstay, but in the caliper and mount itself.

So what finally DID work was pulling some tension on the rear brake hose as it exits the caliper, and then securing the hose tightly in the last guide closest to the caliper... such that the hose holds some tension on the caliper. Instant, total silence. Just have to make sure your hose is routed from the caliper neatly so that pulling on it a bit won't kink it.

Hope that helps someone.


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## ChuckChurch (Oct 4, 2005)

I can confirm, that 160mm Hayes rotor made no noise. I'm pretty sure those CleanSweep G3 rotors are to blame. Talked to Avid, and they said the SolidSweep ones are designed to fix the vibration. LBS is going to try getting it swapped for me.


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## robin640 (Feb 26, 2012)

Breezin86 said:


> They ended up giving me a new frame. Problem is now gone. What a pain though.


I recently bought a new 2011 Stumpjumper FSR comp in the medium size. It too has a very bad rear brake noise starting after about 100 miles. Just found out there are a bunch of people on-line with the same problem.

Going to call my LBS tomorrow to see what they have to say. Wish me luck.

-Ron


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## robin640 (Feb 26, 2012)

Just contacted my LBS and they want me to do the following:

Loosen the rear brake caliper
Spin the wheel and apply the brake before the wheel stops spinning
Tighten the caliper while continuing to hold the rear brake lever from the spin


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## robin640 (Feb 26, 2012)

oh yea, they said a lot of disk brakes make noise.


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## asphalt_jesus (Aug 13, 2010)

robin640 said:


> oh yea, they said a lot of disk brakes make noise.


You guys paid LOTS of money for these bikes and they flat out don't work right. And yet all of you just take the Specialized and other brands punishment. Why?


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## Raxik (Oct 21, 2012)

crux said:


> This is a fun one. I had this happen to a guy and nothing would cure the issues. THe vibration was so bad you could feel it in the seat. It was a FS bike and even after facing the tabs the vib remained. New brakes same model were tried and vib. remained. Went thru quite a few different attempts. What finally fixed it was getting a different brake adapter. Think we put on a Formula one and it went away. Prior to that we did a shimano, hope and Magura Adapter and the noise & vibration remained.
> 
> This will be annoying, but swap out one component at a time till the noise is gone.
> 
> I'd also check the frame for potential cracks in the area. However small that could be a potential source, but unlikely.


I was also reading through everything becuse I gt this annoying resonance once I installed new Shimano SLX with Shimano rotors RT66. While front brake is a joy to ride and use, a rear one makes this problem.

After reading this post I realised that up front I have a 180 mm adapter from Shimano, and on the back I have old one that I got stock with Avid BB5 brakes. Maybe this will help me, so cheers m8, starting hunt for the rear Shimano adapter.


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