Cooked Disc Brakes?

[jimo746]

Tried a new trail today and found a nice long downhill, however towards the end of the downhill I definately noticed brake fade from the front, and when I stopped at the bottom the front disc looked blue-ish and the pads were smoking :shock: The rear brake was hot, but seemed normal.
Now the front disc has a brown tinge to it, although it seems to work fine.
I have had smoking brakes before, but never a brownish disc :?

Brakes are Tektro hydraulics, disc is a new XT 180mm.

Is the disc going to be ok?

*I did use both brakes, but always seem to use the front a bit more.

 

[DA-EVO]

Tried a new trail today and found a nice long downhill, however towards the end of the downhill I definately noticed brake fade from the front, and when I stopped at the bottom the front disc looked blue-ish and the pads were smoking :shock: The rear brake was hot, but seemed normal.
Now the front disc has a brown tinge to it, although it seems to work fine.
I have had smoking brakes before, but never a brownish disc :?

Brakes are Tektro hydraulics, disc is a new XT 180mm.

Is the disc going to be ok?

*I did use both brakes, but always seem to use the front a bit more.

Which XT disc is it? If you go on the flat for a while, and brake gently for 10 seconds, let go 10 seconds, increase pressure for 10 seconds and repeat a few times, does it clean up?

What material are the pads?

 

[jimo746]

Difficult to get a pic if it, but this is the best I could do...

 

[jimo746]

Pads are Tektro's finest lol! Stock pads that came with the brakes, so probably organic?

 

[DA-EVO]

Did you clean up the brakes prior to changing the disc or were the pads new?

I bought a similar rotor recently (not used it yet) there were some pad types listed on the box for it, from memory.

Is that just the way the pic was taken, or is there scoring in the middle of the pic / middle of the braking surface?

 

[jimo746]

No, I just bolted the new (bigger) rotor and adapter on.
Plenty of life left in the pads.
It's just the "rings of Saturn" effect in the pic. There's no scoring of the disc.

Braking power seems ok, just the disc has discoloured from the heat?

I'll remove the pads later, they may be glazed too...

 

[Matthews]

If they still work don't worry about it , I did that the first time out with the hopes on (i got from you I think) dropping back into Holmfirth , no problems since and they went back to normal colour next ride , btw finally killed the kevlar pads that were in them over Xmas and replaced with sintered, soooo much better .
Matthew

 

[02gf74]

it'll be fine. blue discolouration is actually higher temperature than brown.

my theory of braking - and I am happy to be proved wrong - is to apply brakes hard, then release. you get the brakes hotter so they dissipate more heat (heat transfer is related to temperature diufference) so work more efficiently than if you kept them one all the way down.

whatever you do, do not put your finger on hot disc to see how hot they get - you'd be surprised as well as being the owner of a sore finger.

 

[Mindmap3]

That's a good effort. Is that not an Ice Tech rotor! Looks like mine which are supposed to deal with heat better than a normal rotor.

If it is an Ice Tech one and it's got that hot, keep an eye on it because there are people who have managed to melt the aluminium core!

I've discoloured Hayes rotors in the Alps and they were fine so I'd not worry too much.

 

[Anthony]

It looks as if it was the pads that were cooked, rather than the rotor damaged?

I've just ordered some sintered pads (for Hope Mini), so I'm hoping that all those who say they are far superior to standard non-metallic pads are right!