Bad set of pads, imitation Shimano pads, are your rotors metallic pad compatible? If not, your chewing up the rotor which may be adhering to the pad surface.

 

They're legit pads, I made sure to check rotor compatibility before spending money lol

 

Technically you can’t “glaze” metallic pads. “Glazing” is when you reach the materials melting point, that’s never going to happen with a metallic pad. It’s something that happens with organic (resin) pads. So either they aren’t full metallic, or something else is going on. Shiny does not mean glazed. Shiny is normal because the friction is going to smooth out the material just like polishing metal. The bedding in process leaves small particles of metal pad embedded in the rotor. It is these particles that create the actual braking friction. That is why the bedding process is so crucial.

 

Right. So either my bedding in process was wrong or the pad is contaminated? I'm 99% sure they're metal, they say in big fat letters METAL on them and that model number I mentioned earlier is what I got, which is supposed to be metal.

 

the performance went down noticeably afterwards, with streaks on my rotor. Took apart the pads to find that they are glazed and shiny.

Streaking sounds like contaminated pads. Sanding doesn't remove oil contamination.

 

Right but at no point did they come in contact with any liquid or oil. The only thing that I can think of is perhaps they got contaminated a bit when i placed my finger on one of them during unboxing. To me it's weird that they worked okay with no streaks or noise until the first hard stop. I would imagine that if they were contaminated they would squeak and deliver sub-par performance at all times, but gentle stops had good bite, no streaks and no noise.

 

Buy aftermarket pads, or bigger rotors. I don't think you did anything wrong.

 

I have read not to use brake cleaner on the rotors as it leaves a residue. Bike brakes don't get as hot as car brakes to burn it off. Just use IPA.

 

Yup. and this is possibly the whole problem if OP keeps using it. get new pads and either torch or replace the rotors if thats the case and from now on isopopyl alcohol only. Brake cleaner is for cars, auto brakes get hot enough to burn that residue off and are far less sensitive to contamination than lightweight finger-powered mtb brakes.

 

I thought the point of brake cleaner is it's not supposed to leave a residue. Otherwise why would I use it instead of something else?

Op, I would replace the pads. Sounds like the ones you got are bad. Maybe they're not fake, but maybe there's a manufacturing defect or maybe they're just contaminated. Frankly I've had similar issues with Shimano OEM sintered pads and solved them by replacing with another brand (Galfer).

 

I've never had shimano sintered/metallic pads glaze. But i did glaze a set of resin pads. Do you accidently get resin pads by mistake?

 

I don't think so, the model number is for metal pads and they say metal on the back.

 

Remove the pads, torch each pad for 45 seconds with a propane torch. Douse with water, try again.

 

Don't forget to do the hokey pokey and turn yourself around, cause that's what it's all about.

 

Thanks for the input everyone. Would it be possible that the pads are contaminated, since I may have put my finger on the surface of one of them when unboxing them?

 

Sounds like you did everything right - I think you got a bad set of pads. You'd have to be putting in a ton of vert to wear metallic pads down to the backing plate in a month, and chipping is never normal.

Just touching the pads while installing isn't going to cause the symptoms you're describing (unless your hands were covered in grease/oil) but it does sound like they may have gotten contaminated somehow. It's possible that your calipers are leaking and causing problems.

 

I have thought of the caliper possibly leaking but the pistons never fell out or anything like that. They are kinda dirty however with tons of brake dust, I was thinking maybe some of the brake dust came loose and got between my rotor and pad? I always forgot to try to clean the caliper with brake clean and inspect for leaks.

 

I think the only thing you did wrong was get your brake pads too hot-you messed up by riding too fast while weighing too much, causing your pads to glaze. The fact that the same thing happened over and over after you sanded the glaze off is the giveaway to me. You need to keep your brake pads cooler with bigger rotors or buy different pads and hope they are harder to glaze. Maybe try finned metallics.

 

Right but I've heard from numerous sources that metallic pads can take a lot of heat compared to resins? Then again if I'm not mistaken metallic pads do generate more heat than resins and on an equivalent braking test the metals would get hotter? The situations that I'm in do involve like 3-6 seconds of standing on the brakes hard.

 

You are overthinking this. You need new brake pads anyway, 'cause you sanded the life out of them. Just try better pads, like finned metal, or Galfer Pro, and see if those work. If you are still glazing get bigger rotors.

 

There no way Galfer pro is going to last as long as Shimano metallic. I’m dubious on whether the cooling fins do much either.

 

Can you take a picture of the rotors and pads?

 

Will post one tomorrow

 

IMO no reason to discard the existing brand/model of pad as though it's not a bad set of pads. Sounds like a bad set of pads. At least buy another set and see.

 

Some interesting assumptions going on here.

 

Bedding in organic pads is very important for a different reason than metallics. You actually need to get the pads hot enough to release the oil in the surface layer to produce a "dry" layer on the pads. In use this dry layer then works it's way down through the pads as they wear. If not done properly the first hard stop greases the rotors.
Shimano offers several upgrades to remove heat before it gets to the pads, and before it gets to the 2 piston calipers.
Shimano Icetech rotors from the XTR/Saint groupset. They run much cooler than solid steel rotors. Freeza versions run even cooler and have more metal to prevent bending. They dump a lot of heat before it get's to the pads. RT-86 are the 6 bolt Icetechs, RT-M905 are the 6 bolt Freezas. They used to be Centerlock only.

ICE TECHNOLOGIES FREEZA | SHIMANO BIKE-EU

To Build Closer Relationships between People, Nature, and Bicycles. We believe in the power of cycling to create a better world as we move forward. We inspire all people to enjoy our products in their everyday lives and where they take them.

bike.shimano.com

With the problem you're having you should probably step up to the 203mm size. If you stick with 180 I would get the Freezas.
Shimano J04C pads may help solve your problem. But with brakes I would want a bigger safety margin than that.

SHIMANO DISC BRAKE PAD METAL WITH FIN J04C-MF 1 PAIR | SHIMANO BIKE-EU

SHIMANO DISC BRAKE PAD METAL WITH FIN J04C-MF 1 PAIR. SHIMANO Original parts and the right maintenance makes this excitement possible for you, every day.

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Planet Cyclery is having a going out of business sale. They have some Centerlock rotors on sale there. M800, M900 are the numbers for those.

Sorry about that I see you're using the RT-66 which are 6 bolts. The RT-86 can be found discounted several places. If money is tight the 180mm can be found around $45 at Jenson. Discounts on the M905 are harder to find.

 

Does the OP have centerlock hubs?

 

Nope, 6 bolt, Forgot to specify, it's a 2012 Trek X-Caliber.

 

Here's some pics of the carnage. The uneven pad wear is probably my fault. The brownness on the rotors is concerning me - in the past i had contaminated pads with hydraulic fluid on the exact same rotor model and it too had these brown streaks on it.

 

View attachment 2097183 View attachment 2097184 View attachment 2097185 View attachment 2097187 View attachment 2097188

Here's some pics of the carnage. The uneven pad wear is probably my fault. The brownness on the rotors is concerning me - in the past i had contaminated pads with hydraulic fluid on the exact same rotor model and it too had these brown streaks on it.

Are those not "Resin only" rotors??

Edit: Nevermind, I see you have RT-66. That said, those pads are knackered and I wonder if that's contributable to over-zealous sanding and the use of brake clean? They look contaminated and like the material is falling apart.

 

I edited in a 6 bolt answer above.

 

I was answering a similar question on Reddit and found some Shimano fine print.
"203 mm RT-MT905 operates 100°C cooler compared with a 220 mm stainless steel disc"
This would put the 203mm RT86 at -50*C vs 220mm steel rotors. The $45 RT85 180mm should be about even, and would bolt onto that bike. Save a few grams too.

 

One of the (many) failure modes for hydraulic brakes, especially really old ones is the pads not retracting all the way and dragging some. This should be easy to check for. Apply the brakes hard and release them on level gorund, and then see if the bike coasts away freely. Sometimes you install new pads, and it pushes the piston back into a corroded area in the caliper.
DOT fluid absorbs moisture, but mineral oil lets it collect in the bottom of the caliper. Also leakage into the piston area from the outside can tighten things up there.

 

Another thing that can cause drag is if the lever doesn't return all the way and open the return port for the fluid. Them heat will expand the fluid and slowly apply the brakes. Or it could be clogged for some other reason.

 

Thanks, I'll try to check that. The caliper was misaligned for a while which i didn't notice cos I ride with headphones on. I adjusted it recently, and didn't notice any form of the brakes dragging after releasing them. I did bleed the brakes myself and perhaps haven't done a splendid job.

 

If the rotor was over heating the discoloration would likely extend beyond the contact area and down the rotor "spokes" somewhat.

 

Also, you do have the option of using an Avid 185 rotor, as opposed to getting an adapter for your Shimano caliper. But, I think if it were me, I'd get the Shimano adapter.