[Closed] Rear brake screech/vibrate through entire frame

Firstly do you have any copper slip on the back of the pads? Secondly and I'm not 100% on this but are the disc mounts faced? I presume these are ali even in a carbon frame but someone will help you out no doubt.

Anyway, when mine squeal I use copper slip and it quietens right down.

I've tried copper slip and it just made a mess, not even sure what the point is.

whenever i've had noise/vibration that bad its been either contaminated pads or having putting the rotors on the wrong way round (they have a rotating direction, usually printed on them).

If you're not sure its sometimes worth biting the bullet and buying new pads, cleaning the rotors and trying the new pads in them. If it still squeels then at least you've got a spare set of pads, and you can rule out contamination.

i've had it on a FS bike when the seatstay bearings had ovalised the seatstay pivots - i'm guessing your is a HT - check for cracks?

my tinbred does this. All through the winter it's been silent, first sign of summer and it's howling like a banshee during rag week. Next ride out, assuming it's not pissing down I'm going to swap out the superstar sintered pads for a softer compound and see if that has any effect.

Maybe the hose vibrating. clamp it tightly to the seat stay (or chain stay) whichever way it's routed

Copper slips sounds an idea, not used any but have got some from when the car brakes were squeaking.

Checked the frame for cracks, all looks good to me though.

Going to try swapping the front / rear pads next I think. If that doesn't work, I've got a new set of alligator pads I can try.

I had the same thing on one of Mrssssu's bikes.
Things I tried were.
Different brake pads.
Different rotors.
Facing the frame. Again.
Ziptying the hose tighter to the frame.
Different rear wheel.

None of these really helped solve the problem.

My solution was to take the Avids off and replace them with a second hand pair of LX's. Been problem free since

Glazed pads? my hayes seem to glaze quite quickly and make some very disturbing noises, put me in mind of a juggernaut pulling an emergency stop. this co-incides with crazy grabby stopping. Sand the pads off a bit?

I'm still really dubious about the copper slip idea, whats the principle behind that exactly? the pads aren't vibrating in the calliper surely, and if they were it would be enough to overcome the slight stickiness of the copper grease. Plus, do you really want a load of grease all over your calliper?

Swapped front pads to rear and still wails.

Checked the rotors closely and they are definitely grooved - I'd bought these both used - maybe they are just at the end of their life?

Think I might bite the bullet and get some new ones - am also wondering if 185mm rotors are really needed - I'm sure 160mm is plenty for my XC riding.

Obviously I'll get new pads as well.

Dave.

Give the rotors a really good go with 120 grade sanding paper, and give the pads a quick go as well. Helps bed everything in better. While you are at it you could also put a tiny chamfer on the leading edge of the pad

Has this just started or did it do this from new?
I'm asking coz my cousin's Scale (with Avid Elixir 5s) howls like a banshee.
And looking at various posts on MTBR, he's not the only one with this issue.

The Avid Turkey Warble/vibration loads on it on MTBR I made it a little better by fitting Hope rotors. In the end gave up and sold them seems to be no cure.

Your rotor/brake dynamics are probably matching the resonate frequency of your frame, if this is the case copper slip etc will not cure. Changing rotor for a different style or size can help as can simple things like tightening your spokes. Good luck

Have a very similar problem with my new Remedy 8 the Elxir CR's cause such a vibration/howl that its painful to stay sat in the saddle from the vibrations (might be OK for the ladies 😉 )

Now I'm not exactly new to disk brakes or setting them up & have owned Hope,Hayes,Shimano,Magura,Clarks & Avid (BB7) disk brakes with very few issues over the last 10 years.
Mounts are faced, though this should make little difference with the CPS washers.
Tried 2 different sets of pads sintered & Kevlar
Rotor cleaned with IPA (not the beer silly)
Pads hit the rotor smack on together & square.

Might just sell them on and buy some new Hope's?

You have checked that the little tri-align spacers are all the right way around? I had the same symptoms as you and this was my cause. Simple fix?

generally caused by lack of disc mount stiffness and / or an disc caliper that's not quite parallel with the frame / rotor. frame / mount rigidity is the main cause tho, it's most common on ti frames ime.

Hmmmm.

My Scale came with Juicy 5's, and these needed a bleed so I decided to upgrade instead - got me some Juicy 7's as I liked the idea of the pad adjuster. They were originally running a 185mm rotor up front, so I decided to upgrade to a 185mm at the rear (bought used rotor off ebay).

Everything has worked fine for the past few months (so through the winter) since I got the Juicy 7's, and I'm still on the original pads.

Did a nice long ride in the dry without any noise, but then my next ride (3 weeks later) the howling started.

I've got some new organic pads to try, and I'm gonna rub down the rotors with fine grit paper - see if I can get rid of any contamination.

loose rotor bolts or loose bolts on the IS mount.

thats what caused mine anyway!

Copper slip lets the pad move within the caliper without too much friction and noise.

On a bike I have never had to use any.

My disc may squeel in the wet a bit.

Vibration sounds like too much movement-check everything, caliper bolts, disc mount and alignment.

A decent frame you can just wack on a caliper and away you go, some may need facing.

If you're not sure then take it to your LBS.

Sounds like the problem I had on my Spesh FS. Just realigning the pads by eye - so they touched the rotor at the same time - fixed it for me.

The IS adaptor has been sat fine on the frame - not been taken off since installation, at which point I've had 3 months of ace (and quiet!) braking.

Everything is nice and tight - have even had the BB out and re-greased!

Dave.

What worked for me:

Push one side of the caliper out at a time (as far as your dare!),
take pads out & clean sticky out bit of caliper with isopropyl alchohol/similar,
dry,
apply some brake fluid (cotton bud works well for this),
push caliper back in again,
Repeat fo the other side,
Put pads back in,

All sorted, phew! Now I can stop scaring the horses!

Took the advice of CaptainMainwaring (and others) - took off the rotors and lightly rubbed them with very very fine grit paper (180 I think) - plenty of cr@p came off them (even though I cleaned them thoroughly with brake cleaner before that).

Thanks for all the advice and suggestions folks 🙂

Dave.

theotherjonv - Member
my tinbred does this. All through the winter it's been silent, first sign of summer and it's howling like a banshee during rag week. Next ride out, assuming it's not pissing down I'm going to swap out the superstar sintered pads for a softer compound and see if that has any effect.