Rear Brake Squeal

W

Willoadrian

Squid
About 6 weeks ago I purchased a new HT with Elixir 5 Brakes. Since the first ride the rear has constantly "squealed" and sent a vibration thru the rear end when braking. The rear rotor is 160mm.

The bike is currently at the shop from which it was purchased for about the 4th time and still no fix.

Last week the mechanic took the bike out after hours and rode it in order to get a better idea of what I was talking about. Afetr about 40 minutes he was sick of the noise and gave up. The next day he put a smaller rotor on the rear then rode it again that night. Still no solution.

Whilst I am happy with the service from the shop I am getting a little jacked off that I have spent $3000 on a bike that is spending more time in the shop than it is under me.

Any suggestions?
 
Science

Science

Likes Dirt
Best thing i ever did with brakes, and for noise, was loosen the caliper bolts, pull the lever in hard, and tighten the bolts again. This centered the calipers, sat them square with the disk, and killed all the noise.

But, fit the bike man has tryed differant disks, he's robably had the caliper off. That said, many of them just throw them back together. Try recentering the caliper. After that, i dunno, I'm fairly new to Disks on pushies. I don't know how a Bike pad would respond to the various Car pad tricks.
 
D

dcow1

Squid
Willoadrian said:
About 6 weeks ago I purchased a new HT with Elixir 5 Brakes. Since the first ride the rear has constantly "squealed" and sent a vibration thru the rear end when braking. The rear rotor is 160mm.

The bike is currently at the shop from which it was purchased for about the 4th time and still no fix.

Last week the mechanic took the bike out after hours and rode it in order to get a better idea of what I was talking about. Afetr about 40 minutes he was sick of the noise and gave up. The next day he put a smaller rotor on the rear then rode it again that night. Still no solution.

Whilst I am happy with the service from the shop I am getting a little jacked off that I have spent $3000 on a bike that is spending more time in the shop than it is under me.

Any suggestions?
Click to expand...
Is possible that the pads are contaminated with hydraulic fluid? Get some new pads installed. New bike, clearly a warranty issue.

Failing that I hate avid brakes! The juicy 7s I used had a heap of power but were always vibrating through the rotor under heavy braking. I tried everything (new pads, rotors, complete rebuild). In the end I brought some Shimano XTs off ebay. I've owned 2 sets of Shimano brakes, one set is over 8 years old with absolutely no issues.
 
Christo

Christo

Likes Bikes and Dirt
The issue is Avid's 'tri-align' half moon washer system, get rid of them (replace them with flat washers or get a new disc mount) & the squeal will go.

Otherwise, loctite them & do the bolts up TIGHT. it's a recurring issue with any brake with these washers, I've just ditched my Juicy 7's for some Shimano brakes because I'm sick of the constant re-alignment.

It's a great idea in theory...
 
S

Stewiee

Squid
Christo said:
The issue is Avid's 'tri-align' half moon washer system, get rid of them (replace them with flat washers or get a new disc mount) & the squeal will go.

Otherwise, loctite them & do the bolts up TIGHT. it's a recurring issue with any brake with these washers, I've just ditched my Juicy 7's for some Shimano brakes because I'm sick of the constant re-alignment.

It's a great idea in theory...
Click to expand...
So if it is the Tri-align system, why is it that it happens to the rear brake only? I have this problem to.. Only with juicys and was considering of upgrading to elixir r's soon just not sure now
 
R

Raf

Likes Dirt
I will pay attention to this topic, same issue with the BB7 mechs. They wroked fine for about 300km of stromlo single track, then after a self service on the rear end, they started shuddering. I think the pads may have been contaminated with wax/lube...?

I have found that increasing the gap from pad to rotor seems to make it work better and smoother. Dont know why. Just tinkered with it....

What/where is the half moon washer???

Raf
 
fergo

fergo

Likes Dirt
After reading the 4 links above and no-one really finding a generic solution to the problem, I guess you just have to live with it. I have this very loud vibrating noise coming from my rear brake as well. What is different to everyone else is they are not Avids, but Shimano SLX brakes. They are on a 2009 Kona 120 supreme.

I have changed rotors and pads with no luck. I also went down a very big steep hill and had to stop halfway down due to brake fade (could not fully stop - had to run into the upside of the trail to stop) and over heating the brakes and they still made the noise afterwards. Everyone could smell my brakes. If there was any contaminant on them, it would have been burnt and worn off!

I was going to buy elixir R brakesets, but now am hesitant given the very large discussions on this topic of shuddering/vibrations.
 
3viltoast3r

3viltoast3r

Likes Bikes and Dirt
To all the people who have changed rotors, Did you use Avid rotors or replace with different brand rotors?
 
F

frensham

Likes Dirt
One solution to this is to have the disc mount machined so that it is perfectly flat and even. Many disk mounts aren't perfectly aligned and this results in brake squeal and vibration (the squeal is just high pitched vibration). Don't know if this is a warranty job though.
Now, Avid discs are renowned for their funny noises under hard braking - try a Shimano or Hayes disk.
 
willsy01

willsy01

Eats Squid
My SLX rear brake does the same......factory pads though, might swap them out and see if it changes anything
 
3viltoast3r

3viltoast3r

Likes Bikes and Dirt
frensham said:
try a Shimano or Hayes disk.
Click to expand...
Ive had Hayes disc which had the most definitive audio library of a turkey gobble...


Funnily enough I have some shimano rotors which were nice and quiet.....Until my mate crashed my bike and warped the rear rotor pretty badly :mad:
 
fergo

fergo

Likes Dirt
AndySTi said:
Tried re-aligning the caliper?
Click to expand...
Yep, but not facing. Who does this in Melb? Is it a lbs thing or more specialised repair?

My rotors were 09 shimano xt with shimano metal sintered pads.

Rode my commuter last night with juicy 5s and avid rotors and couldnt believe the silent difference. Thinking of changing them over.

Any comments on whats a more powerful brake - 08 Juicy 5's or 09 Shimano SLX with 6" rotors?
 
B

bodger

Squid
Gday mate, I live in launnie too and have had the same problem with about 4 brakes. If the pads are contaminated by hydraulic fluid then try this trick to fix them.

1. take pads out of the brake calliper.(don't pull lever)
2. take the wheel out
3. rub the rotor with methylated spirits (it's an alcohol so will evaporate)
4. put the pads on the ground and pour a bit of metho on them and set them on fire.(burns away hydro fluid)
5. wave a flame over the rotor to make sure.
6. put back together
7. wear them back in
If you have any problems send us a pm.
 
S

sketchyC

Likes Dirt
How I Corrected my Elixirs

I Have a 2010 scott genius and it came with elixir 5s. after my first ride i had this issue with the rear brake only (major vibration of the rear triangle).
asked the mechanic at lbs and he said it was the scouring of the rotors. just the pads vibrating as they are moving with the lines (like a car to the road). cause where i ride is very sanding and rocky, it could have been something that got into the pads and scoured the rotor.
So how i solved my problem:
Took out rear wheel, then pushed pistons back in.
Took out the pads and spring clip.
Sanded the pads a little, (keep in mind to keep them flat)
Sanded the rotor where the pads connect, on both sides.
Attached Spring clip and pads then inserted wheel. Had to re adjust rear brakes and they were fine.

Have been riding it for 3 weeks now no issues. Riding in the rain, damp condition tracks and dusty hot whether. Rear brakes are making less noise then the front under load.
Check if you guys have scouring on the rotor, if so. I dont see why you cant give this a go.

Hope this helps some of us.
 
R

Rolla

Likes Bikes
I had the same problem with my anthem the rear brake only, a 'screaming banshee' noise . Tried sintered pads didn't work went to organic and eventually fixed it and has been ok for 10 months or so. Just carry some pads with you if on a long wet ride as they can wear quick.
 
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