This. I recently upgraded my bb5s to TRP Spyers and didn't notice and difference until I broke them in.

Instructions on my TRPs say it take about 30-40 uses to bed them in. What I would do to accelerate this period is do a few hard pulls then slam on the brakes. They will brake in fast. After one ride you will notice the huge difference.

In the mean time spray with ISO alcohol.

If you get adventurous you can pull the pads and rub on fine sand paper. Just buy a couple sheets of 150-200 grit.

Only a couple passes or just enough for the pads to shine.

Maurice

Exactly. Generally the recommended process is to brake from medium pace to walking pace a number of times and then a faster pace to walking pace a number of times. You want to brake smoothly but firmly to make the whole process even.

Any personal experience servicing disc brakes of any kind? I am not second-guessing, I am helping prioritize based on some knowledge gained from cars.

1) Dirty braking surfaces
2) Air in the lines
3) Bedding in

Cars need hundreds of miles of moderate driving to fully bed in. Many recommend a few runs of max braking to the point you see smoke coming from the brakes. That is what it takes to reasonably transfer pad material to the rotors. Maybe bikes do it faster, but I would not bet on it. But the big point is that bedding in is a small incremental improvement. The OP is experiencing something much worse degrading brake performance.

I'm sure you are right about cars. Also, I have no idea why it could be different for bikes. (I have a few completely non-backed up ideas, but no actual knowledge.) I can say a few things for certain:

1. I have 2 cross bikes, 2 mountain bikes, extra wheels sets (thus new discs) and have replaced discs a few more times. EVERY time I get new discs on there, the brake force is lousy until I bed them in. Every time. It takes some pretty hard stops, helpful to do on a descent and not just back and forth on the road.
2. If this was a MTB/gravel/cross forum, the first 5 posts would've all been: "just bed them in". If there weren't a few other points brought up in the first post, the thread would quickly fall off the front page: case closed.
3. All disc manufacturers, all youtube videos, everyone...always says: you have to bed them in.

I probably should have prefaced my post with something a guy much smarter than me often says "I could be wrong..."

I am curious if the bike bedding-in is really just burnishing off any surface irregularities or contaminants. Or, maybe the pad compound is much softer and lower temperature than car compounds so the process can work without much heat. Regardless, if that works, then that is path. (I would still clean all surfaces with brake solvent.)

I'm going to put my vote in for air in the lines -- incomplete bleeding. I once received a Niner RLT9 shipped from the company. The rear brake caliper bleed nipple had been left just a tad loose (or had loosened in shipping). That introduced a little air to the line -- and exactly the poor performance you're talking about. Not spongy. Just ineffective.

I've been using disc brakes on bikes for a long time and I've never had bike pads need "bedding in." But it's possible, I guess.

I'll report back this weekend after I have a chance to tinker. I'll start by cleaning the pads and discs with solvent, then do some sustained downhill bed-in runs. I don't have the tool to bleed the lines so that will need to wait for professional help.

That's my guess. Both systems work the same way, and certainly cars require a LOT more (removal of) energy to slow down. So, makes sense that the pad materials are different to have the same end effect.

Whoever does the bleed work, I would encourage them to dismount the calipers when they do it. The straighter the path from caliper to bleed port, the better. If you have to pay them an extra $20, it would probably be worth it. (I didn't get my Niner's rear brake working well until I followed this procedure. After I bled it using that method, it was perfect and stayed that way.)

Something is 100% wrong. I have disc brakes on my road bike and they stop so damn well I could throw myself off. Even if they are soaking wet/muddy

I've been unable to find anything on the Shimano website about bedding. The only thing I've found was this:

■ Burn-in period
• Disc brakes have a burn-in period, and the braking force will gradually increase
as the burn-in period progresses. Make sure that you are aware of any such
increases in braking force when using the brakes during the burn-in period. The
same thing will happen when the brake pads or rotor are replaced.

so I went to read the user manual for these, it says,

https://si.shimano.com/...8VR0A-005-00-ENG.pdf
Disc brakes have a burn-in period, and the braking force will gradually increase as the burn-in period progresses. Make sure that you are aware of any such increases in braking force when using the brakes during the burn-in period. The same thing will happen when the brake pads or disc brake rotor are replaced.

So the manufacturer doesn't recommend bedding in the disc brakes. But everyone you ask (as witness this thread) will tell you it's necessary to bed in disc brakes.
I was told the reason my discs were squealing, was due to my neglect of the bedding-in process. Due to that neglect it was now necessary to remove the pads, sand them down, clean with alcohol and clean the rotor similarly, then do the bedding-in.
So far I've found no manufacturer or other documentation that mentions this, or exactly what the bedding-in protocol should be. It seems to be one of the things that all disc brake riders know, but where they learnt it isn't obvious..
one of the many reasons I prefer rim brakes ;-)

Also try brake front and rear separately... if the front brakes better than rear, then it tell me the bleeding wasn't done completely and there are air in the line.

Both front and back suck similarly.

Maybe it’s time to take it in to the LBS and just “pay the man” (or woman) to fix it for you?

I know diddly about disk brakes, even tho I’ve had them on my mtb since ‘13, then gravel bike, then fatty (mechanical), and now my road bike.

They all brake ridiculously well.

One other thing to try, if you’ve maybe contaminated the rotors and/or pads, is to rinse them all off with boiling water.
I’ve had good luck doing that when my bike was honking like an angry goose, and it cleared it right up.
YMMV.

---

float , hammer , and jog

You can just rub them with denatured alcohol. I think boiling water might warp them no?

Just interjecting here... the funniest thing about this thread is that you guys all clearly love your disc brakes... but you don't seem to think there's any irony in all the weird shit you have to do to them... or the fact that a brand new bike requires a long thread on how to *maybe* get them working... ok everyone carry on.

Just to retort...you should also wipe off rim brake pads after getting them all muddy also. I've had disc and rim brakes (still do) on bikes for years. Neither takes any more time or effort to maintain and both have their advantages and disadvantages.

I've had to wipe my disc brakes off once with alcohol because I accidentally got bike polish on them while cleaning the frame. Even then it's because I didn't want to listen to them for the first mile of a ride until it wore off.

Regarding bedding in... I've never personally had to do that either. Maybe it's just happening naturally as I'm riding. But my yearly pad change has never resulting in anything but improved braking.

His disc brake issues sound a lot like business as usual for my tt bike brakes, but at least there's a way to make the discs better...

I had some annoying clicking and pulsing. This was on a new rotor.

We use the 3M GREEN scouring pads to brush-clean metal in the shop.
So I used that on the disk rotor with some gusto.

Smooth now.

Hydraulic brakes - the pads self adjust afaik. Brake caliper alignment is important too!

---

Training Tweets: https://twitter.com/Jagersport_com
FM Sports: http://fluidmotionsports.com