Disc Brakes Screech.
 

I am having trouble with the disc brakes on my 6 week old Rocky Mountain Metropolis YVR bike. They are Tektro Novela 160. The brakes Screech and squeal extremely loudly. To give context to this; to say my brakes squeal is to say Canadians kind of like hockey or New Zealanders sort of like Rugby. The noise hurts my ears and animals run from it with terror in their eyes (ears?).
I have had it back to the bike store where I bought it and they have tried to deal with this 4 times. They have cleaned them , and adjusted them untill they say the brakes should be fine. They say the sound should go away after awhile. I say it never should have been there in the first place and I shouldn't need to run down hills with my brakes on to get this noise to stop. That didn't work anyway, I tried.
What can I do? Are there replacement shoes with softer compounds? Do I buy a boat anchor and stop using my brakes? What?
Here are photos of the brakes.
Thanks.
Red.

If you are using metallic pads, they will always squeal. Check with your shop about what pad compound you have.

Do you have a pad dragging,purple is not a good color for rotors.That 4th picture looks like the rotor is purple.Meaning they got a real workout,or one of the pads is dragging hard.If the pads drag,it will glaze the rotor and make noise.

Noise comes from something loose(rotors,calipers,pads,wheel bearings) or the rotors are glazed/pads contaminated with oil/grease or incorrect finish on the rotors(glazed or too coarse,making the pads jump in the calipers)

I've never had problems with metallic pads(or any pads) making noise when all else is correct.

This got me thinking so I downloaded the instruction manual from Tektro and found that the pads are only held in place with a magnet, they call it a floating pad. There is a locating pin, but they held in the calliper with a magnet. Obviously this will allow more movement than a pad that is screwed down. I am down with food poisoning today so I have not gone to check the movement on the pads.
As far as purple goes, I think it must be a funny reflection. I'm an old fart getting back into riding after many years off (pounds on) so I can't imagine me putting enough energy into the movement of the bike to cause the rotor to scorch to purple. Good observation thought.
The manufacturer has only one type of pad for these brakes, a metallic ceramic.
Thanks for your comments guys.

I had problems with my Avid Juicy rear brake. We tried everything including removing the pads and sanding them a bit. I ended up just getting a new set of pads and the problem was solved. While working on the problem, I even made sure the rotor was true, etc. These things were embarassing as you could hear them a long ways off. Now I'm all stealthy.... well, as stealthy as a Clyde can be.

i hear your pain: after about 3k miles on my BB7s i have pretty reliable squeal at certain times. a couple of solutions work for me (some of which you've already done):
1. make sure the pad-to-rotor clearance is as close as effectively allowable (it looks like you've done this)---a rotor that has to bend further to meet the pads squeals more.
2. non-metallic pad compound (you may be limited here; the organic pads made a difference in lack-of-squeal for me)
3. compressed air for a quick clean to remove gunk build-up; of course you should break them down completely and properly clean them from time to time.
4. new pads, new rotors---pads before rotors, since they're somewhat less expensive (somewhere around 1/3 the price, in my case); sometimes a rotor may have grooves bad enough to make constant squeal, which you can either reface or replace (in my case it's just simpler to replace)
5. learn to live with a little squeal---sometimes it's just more hassle than it's worth it to fix a tiny bit of squeal, unless you require a ninja bike. i just treat it like a warning noise to indicate my braking :D (it usually happens for me on steep incline high-speed braking under a 75# towed load... real trains make the same noise).

Thanks for all of your suggestions. I will try new pads and see, although they only have a couple of hundred miles on them. As far as living with this noise, but I can't do this. It's hard to really get the severity of this sound across to you but it is so bad it's extremely uncomfortable to hear. By the end of a ride I’ve lost all of the calm a good ride normally gives me. Are Disc brakes really worth it? I suppose that is another topic.
Rob.

yeah, if they're *that* loud, then they need to be fixed. as other users have mentioned, are your rotors true and without grooves? new pads will help, but if the rotor is bad, then the fix won't last long. also, when you change the pads, take a moment to clean out the brake calipers from dust and other grime and residue.