Shuddering from mtb hydraulic caliper

[Alex2018]

Hi all,

Since buying this bike theres been this terrible shuddering and grinding noise coming from both the front and rear brakes when applied. I have tried swapping pads, swapping discs, offsetting calipers with washers, realignment ect and still the problem persists. The discs are true and calipers pistons function as expected. The pads are contacting with the usual part of the disc. Its been doing my head in for months now.

I have a theory of the cause but I wondered if any more experienced people may know the exact cause to save further messing.

Here's a video demonstrating the front brake being nearly fully applied and pedalling. The grinding sensation travels throughout the whole frame. I did have a period of bedding the brakes in when the bike was new with some good, large hills, thinking the grinding could have (being hopeful) been bedding in issues.

https://photos.app.goo.gl/1AV75vG8R5gwWUF29

The bike is a Carrera Fury 27.5" MTB with Avid DB-1 hydraulic disc brakes. 180mm disc front and 160mm rear.

(I forgot to mention - the bike is now 7 months old)

Thanks.

 

[wisdom]

You have changed discs and offset the callipers.
Had you not done that you could have gone down the warranty route.
I have no thoughts as to what could be causing it on a newish bike.could something be contaminating the discs and pads?

 

[Tangoup51]

Check that your front wheel bearings have no play and spin freely.
Check your front QR skewer.
Same goes to the rear.

Doubtful any contaminated or misaligned pads would cause such juddering that you've described. The noise sounds like bearing knock from the hub on that video.

If all parts are original, you're still under warranty to take the bike in shop of purchase to resolve the issue.

 

[Alex2018]

You have changed discs and offset the callipers.
Had you not done that you could have gone down the warranty route.
I have no thoughts as to what could be causing it on a newish bike.could something be contaminating the discs and pads?

Hmm, the warranty route wasn't really an option. I worked for Halfords at the time so bought the bike on trade. I also assembled it out the box from distribution. I also had every colleague try to diagnose the issue and even the new trainee techy at my local store. I had then transferred to the preston store and the staff at the new store had a look and their technician. But to no avail.

I have a feeling that when the pads are being pushed inwards in their cradle they are turning inwards so the sound may the the front of the pad hitting the vents on the disc. But thats my final guess...

 

[Alex2018]

Check that your front wheel bearings have no play and spin freely.
Check your front QR skewer.
Same goes to the rear.

Doubtful any contaminated or misaligned pads would cause such juddering that you've described. The noise sounds like bearing knock from the hub on that video.

If all parts are original, you're still under warranty to take the bike in shop of purchase to resolve the issue.

Yep, there's no contamination ect. The hub is defiantly okay and with the thru axle in the front there's no wobble or abnormal sounds from it. Same with rear QR.

 

[Cycleops]

Looks like your only option is to change the callipers.

 

[Levo-Lon]

whip the pads out and sand down the leadind edge.
this will be at the bottom of the caliper , so mark pads as you remove with a permanent marker ect with an arrow.
you only need to make a small chamfered edge.
this may solve it as it seems to be the pads leading edge is catching the disc cut outs.

hth

 

[the snail]

Could be your spokes aren't tensioned properly?

 

[Alex2018]

I'm tempted to sand the pads. I noticed when adjusting the calipers if I left the inner screw loose then i can recreate the exact sound ect by pushing the inner side of the caliper inwards. So it's definitely due to where the pads are contacting on the disc or the angle at which they are.

What I'm going to try first is a trip to Halfords to insert more than one washer to see if I can make it so the leading edge of the pad is contacting a part of the disc with no slots all the way around it ect.

Without the brakes applied the wheels turn in the wind freely with no rubbing. I've built and serviced loads of bikes over the last few years usually problems are pretty easy to find and fix...

 

[Globalti]

Your pads and rotors are contaminated with oil or brake fluid. If the bike judders to a stop with a nasty squawk from the brakes that's the proof. Dismantle and clean everything with alcohol and put the pads in the dishwasher to decontaminate them. Never spray WD40 or anything near the hubs.