Disc Brake Contamination

rwoofer

I'm getting really fed up with my disc brakes seemingly getting contaminated all the time. Basically on my ride today I couldn't even get my front wheel to lock with all the hand pressure I could muster.

Now I'm almost religiously careful about not touching the discs, or spraying anything near them. The worst thing that can happen is some Muc-Off bike wash gets splashed and I hose it off. I do wash the bike quite regularly, I should add. I get the same thing with my road bikes and they don't touch dirt.

So what is causing the contamination? Do others regularly have this problem? Ironically the cheapest discs and pads (resin ones) I had where the only ones that did not eventually get contaminated and I wore them out.

veronese68

Is it contamination or are the pads getting glazed? Usually with contamination you get noise. My rear pads used to get glazed as I never braked particularly hard with the rear. Went through a bedding in type procedure with it and it improved, got into the habit of using it a little harder from time to time and it doesn't tend to happen any more.
If you have gone from resin to a higher performance material that may be part of the issue. Harder pads needing more heat in them to work perhaps, why not go back to resin if they worked better.

steve_sordy

Do you transport your bike on top of or behind the car (ie not inside it)?

If so, you could be picking up road grime that is contaminating the discs and then being picked up by the pads. I was getting lots of squealing and howling. My answer was to fit 8" zip lock sandwich bags, freezer bags, whatever - you know what I mean. Cut half way down on one side only and slip over the disc, so that the uncut side is upstream. Pretty much every time when I get to where I'm going and remove the bags, one side is covered in brown gungy droplets. I'm assuming it's coming from the road and hopefully not the exhaust! Although about 14 gallons of water comes out of the exhaust for every gallon of petrol, so it could be from the exhaust.

You could also use them when lubeing the bike, just to make certain.

I don't buy the bags, my wife does and uses them for all sorts of foodie stuff. I snag them when she's done, so they are in effect not only free, but recycled!

rwoofer

Thanks.

I wonder if glazing is the issue, because I have been doing a lot of riding on the flat recently. Will try some bedding in and see.