To The Point: Disc Brake Pads

Jun 17, 2013 at 22:03
Jun 17, 2013
by Mike Kazimer  
 
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Disc brakes are one of the most significant advances in mountain bike history. It only takes a spin around the block on a bike equipped with old-school cantilevers to be reminded of how lucky we are to have the stopping power and control that modern disc brakes offer. We asked Fabien Barel, Brake Authority's R&D manager (as well as two time Downhill World Champ), about how disc brake pads are made.




What are disc brake pads typically made of?

Brake pads can be divided in two main categories: organic and metallic sintered. The materials which compose the compound are merged together during the manufacturing process thanks to a binder. This binder is in resin for the organic pads, or in metal for the metallic sintered pads. The sintered pads are lot more resistant to high temperature whereas the resin has a tendency to melt and burn which results in a drop in the braking performances at high speed. Plus, the sintered pads last longer.


How are they made? Can you explain what “sintered” means?

STEP 1: Powder mixing

Sintered pads are manufactured using powders.
The friction product contains at least 10 different constituents (copper, bronze, iron, ceramic, graphite…).
Each of these constituents has a key role when the pad is in contact with the rotor (comfort, noise, performance).


STEP 2: COMPRESSION

Once mixed, the constituents become a friction mix which is then compressed using a tool that gives it its definitive shape.


STEP 3: HEATING AND SINTERING

Next, the result is placed on a metallic base and placed in a high temperature oven.
That’s the sintering process: one constituent of the mix melts and attaches the compound to the base..


STEP 4: FINISHING

The pad is finally rectified, checked and packed.

Sintering = technology that allows the transformation of metallic powders into metallic compounds.




Most riders are familiar with how hot rotors and calipers can get after a long downhill. What types of temperatures have you seen during testing? What is the effect of high temperatures on braking performance?

We've seen temperatures of 125 °C recorded with the laser captor during the DH testing sessions.

Extreme heat during braking can cause what riders typically call 'fading.' This is the drop in braking performance that will cause a longer braking distance.


What is “bed in”? Why is this important?

When they’re new, rotors and pads have a slightly rough surface, which decreases the braking performance. That’s why bed-in is always necessary to get the optimal performance from the brake system. The bed-in period allows any roughness to disappear in order to have pads and rotors perfectly flat. Therefore, the contact surface between the compound and the rotor is maximum and braking is more efficient.


What makes one pad better for XC while another one is better suited for DH?

In our R&D lab, we put together different compounds for different uses. In fact, for each use we have a specific pad. It’s important to choose the right pads depending on your discipline. If you just ride along with your MTB, there's no need to get pads for DH racing for example, as they’re designed to be efficient at high speed - they'll still work at slower speeds, but that's not their intended purpose. That’s why we’ve developed the Ceramic, oriented towards DH racing, and the Burly, which is more suitable for leisure or “non professional” use.

www.brake-authority.com
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97 Comments

  • + 127
 It's a nice change to read one of these without constantly being reminded of the company the person works for.
  • + 30
 its nice to see a rider that knows his stuff. so many of these pros dont know jack about their bike except how to ride them and what feels good
  • - 80
 Where did you read that Bowen, you mean R&D? Agreed! I will never buy anything from those basterds! Apparently they have their department in almost every bike company, check that shit out!
  • + 76
 Shut up WAKI you are boring.
  • + 11
 I'm not sure if WAKI knows what's going on
  • + 1
 So what if companies advertise themselves in these articles? They take the time out to write them for you so why shouldent they get something back?

I personally like to know what company I can trust to know what their talking about....
  • + 4
 @dirtman04 its like gwin, what kind of rise you have high rise, low rise? uhhh i dont know, comfortable rise?
  • + 3
 helps everyone. And makes other bikers feel more comfortable about the knowledge they are getting rather then hearing business banter
  • + 3
 @megaturtle :
What is just said here is that for once this article brings knowledge to the reader, not ONLY advertisement. As an example, the sintering process is quite a technical stuff and was well explained, also there were no add in each answer as we are used to.
If you compare this article with the one about bushings you'll get the idea. At the end of barel's interview he is mentionning in one sentence what the brand he works for is making and who it is for. To my mind, it's enough and more effective thant someone repeating again and again he is better than others without really proving it.
  • + 4
 But why does it cost more than car brake pads?
  • + 3
 the 3 common problems with disc brakes on mountain bikes?

1.poor setup

2.poor setup

3. poor setup


also? poor maintenance regime

cleaning bike with aggressive "muck-off" products contaminating disc rotors and disc brake pads, getting overspray from aerosol chain lube, suspension spray or bike polish onto rotors and pads. Leaking hose connectors or damaged hoses getting DOT or Mineral oil onto rotors and pads.


most disc brake systems when setup properly (caliper alignment over rotor, bedding in process) and maintained properly, will cause little problem, and very little noise or vibration (admittedly some bike frames have resonance issues with certain brake systems)

I have lost track of the number of mountain bikes and hybrids bikes with disc brakes coming in for service with terrible setup and filthy rotors / pads

complaining of "needing bleeding", "lack of power", "too much noise", when what it needs is initial proper setup, cleaning, bedding in process and regular maintenance (often nothing more than cleaning brakes after bike wash or heavy riding, with disc brake cleaner and then wiping off with lint-free rag, doing increasingly harder stops on road until noise abates)
[Reply]
  • + 43
 I came here looking for an epic pun thread like the tire pressure article, but to no avail. Brakes my heart.
  • - 9
 I see what you did there..
  • + 19
 There's no stopping it now.....
  • + 22
 I was expecting a Barel of laughs...
  • + 26
 Disc getting ridiculous already. Give it a brake.
  • + 8
 I'll help pad this thread out a bit.
  • - 12
 Love to know how I get neg propped for that.
  • + 13
 tmargeson cool off before you get faded
  • + 7
 When will it STOP?
  • + 5
 When someone brakes the chain
  • + 4
 Such an organic composition of comments, you all make me so proud I could squeal!
  • + 3
 you people have definitely piston my mood, with your lack of funny material.
  • + 1
 DOT right there is how you keep it punny
[Reply]
  • + 24
 I had no idea Fabien Barel did this too. Did anyone else just hear his voice as they read it?

Also it would be good to know which constituent metals do what.
  • - 14
 His name is in the first paragraph
  • + 3
 Jack I think asking what metals do what would be like trying to get Coke to tell you what bit makes it taste the way it does.
  • + 6
 Totally read that with a heavy French accent...
  • + 1
 @ cag

too true. Hmm vegetable extract... tasty tasty vegetable extract. I often enjoy some delicious vegetable extract soda.
[Reply]
  • + 12
 Thank you for all this wonderful information.
  • - 7
 mmmmhm
  • + 2
 thanks. that was super helpful.
[Reply]
  • + 11
 How the hell do you get rid of turkey gobble from Avid Frown
  • + 69
 Buy shimano
  • + 1
 Try A2Z organic pads. Recommended to me by a bike shop in France a couple of years back and I haven't look back since. I still get some in really wet conditions but this disappears once they've warmed up.
  • + 17
 The turkey gobble is good. It means you should stop braking and go faster
  • + 0
 That noise is generally due to miss alignment.
After that you are looking at contamination.

Fabien is right with bedding in to a small degree but bedding in is about starting with clean, non contaminated rotors and moving some pad material onto the rotor.
This is why you usually use clean water to don it, it helps prevent contaminants getting onto the rotor.
Rotors are not flat as flat polished surfaces have never been known for making good friction contact areas.
A little like a car (well a lot actually) brake rotors are not waterproof, if you have a contaminated rotor with brake fluid (which is corrosive) then you have to change the rotor also to stop the squealing and increase brake performance.

Another cause could be that when you fitted you rotor you did not clean the mating surface between the rotor and the hub, or this surface is damaged/not even. You can get anti vibration plates that fit over 2 rotor bolts at a time, never know if they work or not though.
  • + 3
 I've found that Hayes V-cut rotors with Avid brakes are a good solution to the turkey garble! That and organic pads.
  • + 1
 Other option is XTs new rotor as well, works a treat.
  • + 0
 I use SLX rotors with XTR resin pads and find them quite power full and quiet. If I have a wheel off for any reason I realign the caliper after I put the wheel back on as I find that allot of brake noise is from not having the pads perfectly parallel to the rotors and this is more noticeable when they are wet. Resin pads give me more modulation and I know how far I can push them before wheel lock up.
  • + 1
 or just don't brake Big Grin
  • + 2
 The turkey gobble is more likely from bad bed-in process, not mis-alignment, there is no such thing as anti-vibration spacers(those are safety tabs), but it might also help to turn the rotor the direction the pads will force it before you completely tighten the rotor bolts. But probably bad bed-in.

To properly bed them in when new, do a bunch of hard stops when they are new, but don't stop all the way. Sram says do 15, wait for rotor to cool down, then do some more.
  • + 1
 Gobble comes from misalignment.
Buy feeler gauges, the ones that look like swiss army knife. Loosen Caliperbolts. Stick feeler gauges on both sides of disc and calipers. Pull brake. Tighten bolts. Your brakepads should be aligned.

If that did not work you now have narrowed it down to contamination or glazing or overheated disc. Glazed pads can often recover after sanding them a bit. Contamination: Replace pads and disc. Overheated and warped disc. Replace.

Disc quality and longevity have worsened over the past two years. Our 3 month old 200 Avid Discs wear quicker than before.
  • + 1
 Proper burn-in of your pads when new and decontaminate your rotors with a torch...worked for me!
  • + 1
 The torch works sometimes, but depends on the contaminant.
I have rotors where there is no rescue.
I have seen a good mechanic change everything but the rotor and the issue remains....
Check for leaks
Change pads and rotor if you have real concerns.

I like the idea of using a laser temperature sensor... lol (might want to read the manual)
[Reply]
  • + 7
 Definitely a organic man. Can't stand the brake noise it goes through me like nails on a black board. Rather just change pads more often. Plus love the power of organic
  • - 15
 I have precisely opposite experience. Organic pads respond much worse to contamination and once contaminated, they squeal even in the dry. Then some of organic pads loose half of the power in the wet. Get some organic Clarks go ride in wet and you'll have V-brake flashback.
  • + 2
 Odd my dad switched to organic and has has the same XP as the OP, great stopping tower and quiet even in wet on some exlier 7's. My juicy's scream with stinted pads (i think they were used Razz ) in the wet and have no power...
[Reply]
  • + 3
 Prefer sintered most people bed in theyre pads wrong glazing them over with inconsistent brake in on first rides, you wont get that noise if done right, JRA.. Now I dont seem to be able to find Brake Authority for XO Trails? Fabian you the man, help?
[Reply]
  • + 1
 I use SuperStar sintered.. Cheap as they come, utterly reliable, silent and with 203 hope rotors/2012 Deore brakes they have more power than you could ever need, even in the Alps. Flawless. In the UK, you can eat a set of Organic pads in 1 ride if its wet and gritty.. Even well bedded in ones. And that, I think, is the key. Good set up, and proper bedding in are vital!
[Reply]
  • + 1
 Coming back to bikes from a 15 years stop, I thought dics brakes would be netter designed. All brands I have used (avid,formula, etc...) need too much servicing. Only shimano seem to need less but even their feel changes a lot during one ride from top to bottom. Find funny that shimano uses mineral oil supossed to be worse than dot oil for this purpose. Expected brakes to be more reliable.2 cents
[Reply]
  • + 1
 reading this "The sintered pads are lot more resistant to high temperature whereas the resin has a tendency to melt and burn which results in a drop in the braking performances at high speed"

if your thinking of going to a bike park in europe (30 degrees), what king of pads would you take? sintered? FAIL
[Reply]
  • + 3
 HOPE, HOPE n MORE HOPE, best brakes with best customer service anywhere....
  • - 1
 Oh yeah none of my brakes feel as good as my hopes!!! And low service too
  • + 1
 Got myself a set of V4's, on vented floating rota's, simply awesome......
[Reply]
  • + 0
 Why don't companies produce aftermarket Shimano pads for the IceTech stuff? Apparently Shimano can't make enough pads themselves. It also seems that same finned concept could be applied to other types of calipers/brands as well.
  • + 1
 scrub components (made in usa) makes em, www.scrubcomponents.com/Brake_Pads_Overview/CHILL/chill.html
for avid, formula, even pre 2011 shimano
[Reply]
  • + 3
 what kicks ass about metallic pads is that you can burn the oil out of them without rendering them useless in the process
[Reply]
  • + 0
 As much as they are an advance its only the last couple of years, mainly since the release of the most recent shimano brakes i have felt that disc brakes are better now in all conditions than rim brakes. In the dry the Avid Arch rivals i have on an old bike have been better than many disc brakes i have owned over the years. In many respects disc breaks are much easier to live with, but for breaking performance i recon its only in recent years disc breaks have strode ahead. In the wet however disc breaks have always been superior and living in the UK that was the mane reason i invested a small fortune in a set back when they first appeared on the scene.
[Reply]
  • + 1
 I have sintered pads in my clarks skeletal brake and there kicking out loads of black dust which settles on my hub and caliper. Any one know what this is ? It looks like carbon but it doesnt effect performance
[Reply]
  • + 1
 Wow they give great service as well, definitely buying these, got an email reply in less than 20minutes wow, that XO Trails available next month in sintered, be holding out till then!
[Reply]
  • + 4
 Breaks only slow you down.
  • + 89
 Indeed, even more than brakes!
  • + 2
 MrDuck just made my day! Big Grin
  • + 0
 Ikr??? Breaks would surely suck.
  • + 1
 Leg breaks? or coffee breaks? I like a coffee break every once in a while! But it does slow you down.

The worst is broke. Broke really limits your ability to go fast. But it works in the wet and dry.
[Reply]
  • + 0
 Organic pads are great for xc. For true DH I use metallic pads. Harmonic vibrations are the root cause of most squeeling. Try putting in fresh pads and re alighn the caliper.
[Reply]
  • + 2
 Sintered pads may last longer but they are really noisy and the stopping power is really bad compared to organic.
  • + 12
 Only to a certain temp. Once over a certain amount of heat, the organic's power will start to fade off. Metallics won't grab well when cold or at slow speeds, but when you're on a long, steep dh with constant braking they are worth the noise.
  • + 6
 Yea that right, at low speeds until they get hot! Then its the other way around. Don't worry, you will be faster one day... Maybe.
  • + 1
 Oops got beaten to it.
  • + 1
 How about the fact that they're way more expensive too. :/
  • + 2
 Avid and Formula pads costs exactly the same price for sintered and organic and since the sintered pads last longer they come way more cheap in fact.
  • + 2
 sintered for life indeed..price doesnt bother me,. but never had any squeking or noise ? i use em from street to dh..
only resin in the trial pads.. but there are no other options for that,. .
  • + 2
 The noise of sintered pads the worst whenever I do a long climb up into the snow. Need earplugs for the first couple minutes.
  • + 2
 climbs.. snow.. what are you talking about.. ? Razz
[Reply]
  • + 2
 who else read it with a french/fabiens accent?
[Reply]
  • + 2
 Bring back tech Tuesdays.
[Reply]
  • + 1
 this is a nice short article that is to the point with no Padding it out.
[Reply]
  • + 0
 theyre isnt really a super good solution yet for fading in any case yet
[Reply]
  • + 0
 Who else saw the Hope 6ti pads at the top?
  • + 1
 yeaa as mine
[Reply]
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