Are some pads and discs just simply no good?

colstar

I have a 2011 Kona Firemountain. At the end of last summer, I felt it was well overdue for some new rotors and pads. Budget at the time dictated that I replaced them with some lower end parts from chainreactioncycles.
The rotors are Tektro and I forget what the pads are. Prior to replacing the components, the brakes were always sharp and responsive.

I followed online instructions for fitting and was extremely careful to not contaminate pads or rotors. I followed a bedding in procedure (from pinkbike) of several long controlled brakings, with a sharp stop. After this, the brakes howled and did not grab at all.
Since then, I have had the brakes professionally bled at a bike shop and I have tried sanding and cleaning the rotors and pads so that I could bed them in again.

To put it bluntly, they're shit and it's putting me off riding the mountainbike.

Apologies for waffling on but I thought someone might be able to pick up where i've gone wrong. As the title says, are some pads and rotors just not very good or should I be looking for a sticky piston or something?

rockmonkeysc

What pads did you fit?

colstar

Clarks for shimano deore, organic.

cooldad

Most will work fine, but that method of bedding pads in is likely to glaze them.
I just fit them and ride.

felix.london

why change discs rotors?

colstar

I read that it is preferable to replace rotor and pad at the same time as they bed together.

The brakes feel firm with no spongeyness but they just don't grab and the rear howls like a banshee. Does this sound like they are glazed? If so, is it recoverable with sanding the pads/discs and cleaning? Or should i bite the bullet and just replace the lot? I just want to be able to stop!

cooldad

Pads were out quickly and are consumables. Rotors can last years.
Whoever told you to replace them at the same time was an idiot or a salesman.
Could be glazed, couls be contaminated, could be rubbish pads, although Clarkes stuff is normally ok.
I would get new pads (Superstar are cheap and come with Haribo), clean the rotors with isopropyl alcohol, (cheap on Ebay and useful for all sorts of things) and bed them in again.

felix.london

colstar wrote:

I read that it is preferable to replace rotor and pad at the same time as they bed together

Ha! That's crazy talk. Someone is either lying or very confused! I'd get through about 8 disc rotors on the downhill bike each summer!

As CD says - don't bother with 'bedding-in' as such - just go out and ride...always works for me

colstar

Thanks for the advice. I think i will order some new pads and then go from there. I have some STP heavy duty brake cleaner in the garage. Suitable for bike discs or should i go for the isopropyl?

Chunkers1980

Anything that's meant for cars generally doesn't work on bikes. Seems to leave some sort of residue which cars can burn away easier due to the amount of heat they produce in comparison. IPA is the way forward.

colstar

That could well be the root of my problem. I followed a guide on pinkbike for silencing squealing brakes and it said to use automotive brake cleaner. There is some visible (albeit minimal) residue tat has appeared on the rotors after i sanded and cleaned. My chain is sparingly oiled so i'm confident that it hasn't come from there.

One long learning curve!

cooldad

My recommendation would be to avoid anything recommended on Pinkbike.

felix.london

Just shows you, a bit of inaccurate advice and changes what should be a 2 or 3min job of removing old pads and dropping in a new set into what sounds like a complete nightmare of sandpaper, squealing and car brake cleaner! Bonkers!

colstar

Yeah right! I like to try and tackle bike maintenance myself as I think it's all part of the fun. Messing up such a simple job like this puts me off attempting other stuff though!

felix.london

just gotta ask in the right places

cooldad

felix.london wrote:

just gotta ask the right people

FTFY

The Rookie

You did remove the protective oil from the discs when you fitted them right? Otherwise they would have contaminated the pads before you even started.

colstar

I don't think i did initially as I didn't realise that I needed to. It basically sounds like I've messed the job up from start to finish!

The Rookie

We all live and learn, at least it's cheaper than messing up a car!

swod1

i've got a similar problem, fitted some superstar kelvar pads in the rear brake on my bike a few months ago and now i all i get is a loud squealing noise even in the dry.

Took the pads out and they are glazed, i've sanded them back but shall i just replace them, i have 2 spare packs from buying the 4 packs offer.

i have cleaned the rotor with disc brake cleaner.

As i don't race or anything like that are kelvar pads over the top for my use commuting to work and weekend off road use and would i be better off just using sintered pads ?

The Rookie

What disc brake cleaner? Car or motorbike stuff isn't good news on a bike.

If sanding works, use them, otherwise use new.

swod1

The Rookie wrote:

What disc brake cleaner? Car or motorbike stuff isn't good news on a bike.

If sanding works, use them, otherwise use new.

It was a can of muc off disc brake cleaner i used, this stuff

_http://www.evanscycles.com/products/muc-off/disc-brake-cleaner-ec008018

I'm thinking to go back to sintered pads but as i have 2 packs left of kelvar pads i might as well use these first.

The Rookie

As far as I can make out Muc-off sell that for motorbikes which may well mean it leaves a residue that is OK on motorbikes where they get hot enough to burn it off, not on bikes which don't, I'd stick to IPA.

felix.london

I use the Muc-off disc brake cleaner - it was in a bargain bin in the local sports shop. Works well.

swod1

felix.london wrote:

I use the Muc-off disc brake cleaner - it was in a bargain bin in the local sports shop. Works well.

it does seem to work ok when sprayed on the disc rotors with the wheels off the bike, i was unsure on spraying it on the actual pads like it says you can do.

Anyway after cleaning the rotors, the old pads still squeal even after being sanded.

I have replaced both sets of pads front and back which seems to have sorted the issue for the time being.

I'm going to take cooldads word about just fitting them and riding so jhavent bothered to bed them in.

cooldad

swod1 wrote:

felix.london wrote:

I use the Muc-off disc brake cleaner - it was in a bargain bin in the local sports shop. Works well.

it does seem to work ok when sprayed on the disc rotors with the wheels off the bike, i was unsure on spraying it on the actual pads like it says you can do.

Anyway after cleaning the rotors, the old pads still squeal even after being sanded.

I have replaced both sets of pads front and back which seems to have sorted the issue for the time being.

I'm going to take cooldads word about just fitting them and riding so jhavent bothered to bed them in.

Obviously I accept no responsibility if you die.

apple eater

i'm using what is left of the can of carb cleaner tha t i have in the shed to clean my rotors. I only spray it onto the rag and wipe the disks when the wheel is off. I too use the "fit new pads and ride method" no issues so far.

swod1

I thought i would re post in here rather than start a new topic on which is the same thing.

I'm still having the issue with my rear brake, after cleaning the disc with ipa and fitting new pads the squeal is back again.

This is annoying me as i would like to find the cause, this is two lots of superstar kelvar pads that seem to have got messed up.

I've even bought a replacement rotor to see if this will fix the problem and thought of trying some shimano resin pads or would sintered be better to see if the problem is the superstar pads but cant see it, the brake works but with a squeal.

Any other ideas ?

Also to put into the mix why doesnt the front brake squeal then but looking at the disc it has stamped on it resin only but works fine with the superstar pads.

cooldad

Rear brakes tend to be dragged and can glaze.

Best advice, ride it and stay off the brakes.

apreading

I recently fitted new sets of Superstar Kevlar to my road bike, before a tour in Italy. I bedded them in and did a couple of rides in the UK before going, all was well.

On the steep downhills in Italy, the front seemed OK the first couple of times I grabbed it but then squealed a bit but then if I pulled it too hard or for too long, made a horrid noise and lost most of its power. After a rest, it was again fine a couple of times unless I pulled it too hard or too long. I dont know if it got glazed or was just overheating - my guess something to do with the latter because it got worse each time I used it on a descent but then was OK after a rest and cooled down.

The back was fine, but not enough on its own!

After a few days, I switched to a spare pair of SS kevlar for the front and these were fine - a small amount of squeal if used too much but not the loud noise and loss of power that I had with the first set.

Did the first set get glazed? Or was there something wrong with them?

The Rookie

Sounds like something wrong with the first set, that or you were dragging the brakes which is fatal for overheating.