Noisy new SLX Brakes - any advice please

offshore1

I have just bought a new bike fitted with Rockshox Recon Gold RL fork (120mm 20mm axle + taper) and Shimano SLX brakes (180mm F / 160mm R rotors).

Thats a cut and paste from the bike spec - its the first time I have owned a bike with disk brakes, and dont know anything about them.

On my first serious run, the front brake area is making quite a severe screaching / grating when I AM TRAVELLLING DOWNHILL AT MEDIUM TO FAST SPEED.

It doesnt make this noise during normal travel and my inexperienced eye hasnt yet seen anything looking amiss.

Could anybody please suggest what the problem is???

Any advice appreciated.

nicklouse

so have you bothered to have a look at the topics on this subject in the FAQs? try that first.

offshore1

You stupid sad little prat.

estampida

have you bedded the brakes in ? (there is a grime time for that)

take out the pads is there poop on them ?

swop them for sintered pads ? (superstar)

otherwise they are just bedding the slow way and the noise will go

offshore1

Thanks Estampida.

Perhaps the brakes are bedding in, but what confused me was that it was very much more severe when I was going downhill.

At a similar speed on the horizontal there was little or no noise.

I wondered if it was something to do with the brake housing arrangement being affected by the fork being compressed - as though something had been installed incorrectly / tensioned / adjusted.

I need to inspect the fork again - and the pads as you suggest.

nicklouse

offshore1 wrote:

You stupid sad little prat.

so i take it you have not read the FAQs then?

bungalballs

I had a similar problem when my bike was new - although my Brakes are Elixirs, it could be the same thing.

When my brakes were hot, e.g. downhill sections, the brakes would screech/grate, then for a while afterwards would warble like a grumpy turkey.

I used a piece of sand paper (the stuff you get in puncture repair kits is about the right grade) and sanded off the face of the pads to get rid of the sheen, made sure the edges were smooth, and also sanded down the leading edge very slightly to give a 45degree angle. The noise dissapeared straight away.

I have to do this each time I get new pads or the turkey returns!

nicklouse

Bungalballs
what is happening is you are exceeding the heat capacity of the pads and they are glazing over.

again have a read of the info in the FAQs for solutions.

offshore1

I think you could be on to something.

I was travelling just as fast on the flat, but the brakes were used for less time than going downhill I suppose. I did get a bit of the post grumpy turkey too.

I assumed the problem was fork compression / brake mounting related, but very possibly not.

Thanks for the replies

bungalballs

Hi Nicklouse,

I'm not convinced it's heat related; the noise is only when pads are new, and once sanded the noise never comes back through the life of the pad. I got the discs so hot on runs in Morzine that I could smell them when travelling at speed the discs discoloured. No turkeys until I eventually replaced pads whist over there, then same thing, until sanded, and problem hasn't come back...

Offshore - let me know how you get on!

nicklouse

then I put it down to incorrect bedding in which has cause a glazing over.

getonyourbike

offshore1 wrote:

You stupid sad little prat.

Well, that's not a sensible way to go about things if you want advice. If you did what Nick said then you'd already have your problem sorted. :roll: People are helping you out of the goodness of their heart, so don't be a d*ick

cooldad

I thought he was referring to himself for not looking at FAQ's

getonyourbike

cooldad wrote:

I thought he was referring to himself for not looking at FAQ's

If only :roll: