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Posted

I bought new bike with Elixir CR brakes. I took it for it first ride and about 15 km into the ride it developed a horrible noice everytime i use the back brake. It sound like steel on steel when using the back brake. At that stage I thought it could be because the bike is new and the brakepads need to set probibly.

After the ride i washed the bike and look at the pads and could see that everything is fine and the pads is still thick. Yeserday i took the bike again for a ride. Everything was fine and without any noice untill about 20 km in the ride, and then i heard it again and continue untill the end of my ride. Somebody actually siad that it is only dust making that noice. My other bike got Shimano brakes an i never had any of these scratch noice coming from them. What can that noice be and how can i fix it.

Posted

is it a warble/squeal/screech? Did this start after you rode on some dusty trails? what rotor does your bike have? I ask this, because for 2012 IIRC, avid has changed the design of their rotors. One reason cited for the change was the infamous 'turkey warble' that apparently the older G2 and G3 rotors made.

 

G2 Cleansweep:

http://www.sram.com/sites/default/files/styles/product_hero/public/images/products/rotors/2012-g2_cleansweep-large-en.jpg

 

G3 Cleansweep (note, the image below is not of the finished product. It has further machining around the center as with the G2 above):

http://www.sram.com/sites/default/files/styles/product_hero/public/images/products/rotors/g3_203mm_large.jpg

 

Avid's two latest rotor designs (not only a different design, but now offering standard rotor sizes: 140/160/180/200mm)

 

HS1:

http://www.sram.com/sites/default/files/styles/product_hero/public/images/products/rotors/hs1_160mm_large.jpg

 

HSX (6-bolt shown below. Also available with centerlock):

http://www.sram.com/sites/default/files/styles/product_hero/public/images/products/rotors/hsx_160mm_large_1.jpg

Posted

I just went and look and it is definitely the G3 one I have on the back. The bike only did about 75 km now. Is it a common problem and if so, I should probibly change the disk?

Posted

I had the same problem, and yes its a comon problem with those brakes. I changed to different disc and pads and it was better. I dont know what it is with those Elixier CRs, I decided that i will never use Avid brakes again, but as it is I got the new avid elixcier 7's now and they dont have that squeel sound.

Posted

i guess i've been very fortunate, in that all my brakes have been avids (juicys, various models of Elixirs and Codes) using G2s, G3s and now the HS1s (cos they dont stock the G3s anymore :( ) sizes from 160 to 203mm, and no warble. Not even once. Yes, had some dust-squeals that were easily fixed b cleaning my rotors, or just using the suckers. But no annoying warble. Neither have i ever had persistent alignment issues. I guess i was just that lucky with Avid.

 

But, a redesigned rotor certainly lends credibility to any claims of how common the warble noise problem really was. Maybe try the new rotors and see if they give you any grief.

Note: the new 180mm and 200mm rotors will require new mounting adapters. 140mm and 160mm wont as the old G and new HS-series rotor mount adapters are fully compatible ito those specific rotor sizes.

Posted

Also have the same avid cr squeel problem,especially when they become hot on long downhill.New bike has shimano XT ,s .Next change to old bike will be XT,S period!

Posted (edited)

Bedding in new pads/rotors correctly is very important and not something many people are aware needs to be done to prevent high spots etc on the rotors. The noise is vibration/oscillation developing , the resulting sound is the rotor singing in beautiful unison :)

 

Nothing can grate the edge of your nerves quite like the screeching wailing of disc brakes. The Avids have a well documented issue with squealing , but its common to many different makes of brake , esp when wet!

 

Here's some interesting info I had saved:

 

Why MTB Disc Brakes Howl - How to Solve it

 

What makes brakes howl was explained to me by Wayne Lumpkin, the founder of Avid Brakes and a vast reservoir of information about everything disc brakes. This is what Wayne said:

 

As the brakes go through the break-in period, they don't begin to stop with authority until some of the brake pad material is deposited on the rotor as the two components bed together. If the pad cuts through this layer or the layer is laid down irregularly by an improper break-in interval, the pad jumps a tiny bit as it hits a damaged area, digs in, jumps a bit and then digs in again a short distance beyond. The sequence creates an oscillation which continues onward, creating a microscopic series of waves around the circular braking track. Once the pattern is created, the rotor essentially becomes a steel recording disc that is programmed to squeal - and it can't be erased simply by switching to new pads. Brake squeal is most commonly caused by a weak initial break-in period, with the introduction of impurities like chain lube or chemical bike cleaners to the braking surfaces as a close second.

 

Arrest the Squeal Before it Begins

 

Wayne says to break in your disc brakes with a series of very firm stops from a reasonably good speed before you get out on the trail. This properly deposits the pad material on the braking surface of the rotors. Typically, most riders drag their brakes lightly around every corner in the trail, as well as down easy descents. Lightly dragging a new set of brakes is a perfect recipe to create brake howl - which is why you see so many cross-country riders with noisy brakes.

Edited by SkyLark
Posted

I remember Johan Bornman berating my theory about squeal that actually lines up with that which u just posed Skylark. I'm sure i have a huge slice of humble pie here somewhere... :P

 

As for breaking them in, that's pretty much how i've always done, despite being oblivious to Avid's recommendations. Actually, i give myself too much credit: i change pads, and then just go ride like I would any other day, but wonder why the heck i'm still hitting mach 9 into a corner i'm supposed to be slowing down in.. :lol: fun fun fun!!!

Posted

Thank you to everybody comments. I took the bike back to the bike shop and they sorted the problem out for now. The rotor was not straight and the brakes was not properly aligned with the rotor. They claimed that they had sorted the problem out.

 

In the meantime knowing and seeing from other people comments, i started to look arround for other rotors. I currently got 185 in the front and 160 at the back and not sure who can supply, for example XT rotors in this sise.

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