Massive brake fade

User avatar
Nate
Posts: 3149
Joined: Mon Oct 20, 2008 8:49 pm
Contact:

Massive brake fade

Postby Nate » Wed Dec 10, 2014 8:26 am

I've been on discs for a while - BB7's have been the standards on my commuters.
Old commuter was 14.5kg of steel - for a 45km daily commute with 950m of climbing each day...

I've tried most pads, Avid sintered were solid, Clarks never faded (cause they never grabbed!), EBC Golds were the best so far - step up from the avids.
Resins not so good - i'm 93kg & they didnt have the power on long desents.

New bike - Canondale Synapse, discs front & back & a LOT lighter!
Didnt stop as well as the old heavy bike with the stock pads.

Got some Kevlars from Disco, wow - solid improvement - really really happy.
grabby, consistent & much better performance. Ran them for about 3 weeks.

Swapped over & put the BB7 on the front & put in the Ceramic pads.
OMGosh - WOW
MASSIVE stopping power... minimal bedding in too, such huge amounts of effortless braking... until...
2 descents from 40-50km/h to s stop, space between them to cool
2nd descent - complete fade, brakes went out the window - shocked!

had a look & it appears they cooked!
REALLY disappointing... *might* switch to the HS1 rotor, but might have to chuck the ceramics & go to Kevalr on the BB7's...

Pics of the results...
noticeable discoloration on the disc, and chunks missing from the pad material :\
Image
Image
Image
Image
Image
Image

stuff removed from the rotor:
Image



Look cooked?
The HS1 rotor apparently is supposed to help with heat, so might be worthwhile to swap it out... anyone else seen pad breakdown like that?
Any recommendations for Discs?

User avatar
MichaelB
Posts: 8371
Joined: Tue Feb 20, 2007 9:29 am
Location: Adelaide, South Australia

Re: Massive brake fade

Postby MichaelB » Wed Dec 10, 2014 9:07 am

Maybe I need a coffee, but what brad pads went back in the BB7 that really faded ?

What disc size ?

My comments from my experience. Same body weight ( :( ) and do plenty of hard stops on some of my descents, with a classic series of hard stops being for 15km/hr hairpins don a 10 - 12% slope from 80km/hr. So, working the brakes hard, and they are close together.

Re discolouration : Have seen a similar thing on my discs. Just means they got hot. No problem.

Re material from disc : Just brake pad dust. No problem. Some will do it more than others.

Re stopping power : Most pad materials will have a heat range where they work well. Some work great from cold, but will lose power when hot, some the other way around, some consistent over a wide heat range etc.

Here is my feedback re the pad materials that I have tried on my Avid X0 Trail calipers : (180mm front Shimano RT86 or Hayes V7)

Avid Organic : Pretty good, esp cold, not bad when hot, but squeals like a stuck pig when wet. No noise when dry.
Avid Sintered (Metal) : Much better initial bite, and good when hot, no fade. Same when wet.
EBC Green (Resin) : Not happy at all. Once warmed up with several hard stops, good for remainder of ride. Next morning crap again. Thrown out next day.
Uberbike Sintered (metal) : Great initial bite and worked well when hot, but after getting hot, squealed REALY bad, even to the point of vibration. Took them off for a while. Then put back in some months later, and better. Have worked out when they do squeal, quick squirt of water settles them down :?: :?:
EBC Red (Resin) : Haven't tried them yet, but have them sitting there ready to go.


My conclusion is that you reached the limit of the pads re heat. Try the same run with the Kevlar pads and see what happens.

When I had the BB7 on my Argon18 (front disc only), I just had the std pads and never had an issue re fade.

User avatar
silentbutdeadly
Posts: 2294
Joined: Fri Apr 09, 2010 9:52 am
Location: Somewhere flat...

Re: Massive brake fade

Postby silentbutdeadly » Wed Dec 10, 2014 11:21 am

MichaelB wrote:My conclusion is that you reached the limit of the pads re heat. Try the same run with the Kevlar pads and see what happens.


What he said...

...but I'll add that IME the so called heat shedding rotors aren't that much better at shedding heat plus they are far more prone to warping and damage due to impacts.
Ours is not to reason why...merely to point and giggle

User avatar
Nate
Posts: 3149
Joined: Mon Oct 20, 2008 8:49 pm
Contact:

Re: Massive brake fade

Postby Nate » Wed Dec 10, 2014 12:13 pm

silentbutdeadly wrote:...but I'll add that IME the so called heat shedding rotors aren't that much better at shedding heat plus they are far more prone to warping and damage due to impacts.


hmm i've run Avid HS1's for a while with no issues on heat/warping - i'll throw on a space HS1 & look into the Icetek maybe.

Front Rotor = 160mm
Pads that faded were "Ceramic Pro" - http://www.discobrakes.com/?s=0&t=8&q=compounds&
There's apparently special fibers that "insulate the heat from the braking system" - but then where does it go...

Will try the Kevlar in the BB7's and see how we go.
Then onto new rotors - the upgrade from G2 Clean Squeaks to HS1's was noticable on the old bike

User avatar
jules21
Posts: 10331
Joined: Thu Apr 02, 2009 11:14 pm
Location: deep in the pain cave

Re: Massive brake fade

Postby jules21 » Wed Dec 10, 2014 12:42 pm

Nate wrote:MASSIVE stopping power...

brakes are really just heaters. the more stopping power, the more heat.

User avatar
Thoglette
Posts: 3326
Joined: Thu Feb 19, 2009 1:01 pm

Re: Massive brake fade

Postby Thoglette » Wed Dec 10, 2014 1:48 pm

jules21 wrote:brakes are really just heaters. the more stopping power, the more heat.


+1 I used to play with modified sedans - stopping them is a challenge

Fade is a three step process -

1/ first gas builds up between disk and rotor - slots and gaps can clear this away
2/ second the pads start to met (as you found)
3/ finally the disk loses structural rigidity and either buckles or cracks

You need bigger disks; harder pads and better cooling. Can you get a ventilated disk yet? Also, those pads "that never gripped" are possibly the ones to use - once they get hot.


I remember one pad compound we used for long races was so hard that we had to manually manhandle the car on/off the trailer as the brakes were completely useless when cold. Getting out of the pits and down the ramp to pit lane for the first time was "interesting". Not something you'd want on a road car
Stop handing them the stick! - Dave Moulton
"People are worthy of respect, ideas are not." Peter Ellerton, UQ

User avatar
MichaelB
Posts: 8371
Joined: Tue Feb 20, 2007 9:29 am
Location: Adelaide, South Australia

Re: Massive brake fade

Postby MichaelB » Wed Dec 10, 2014 2:08 pm

Nate wrote: ...
Pads that faded were "Ceramic Pro" - http://www.discobrakes.com/?s=0&t=8&q=compounds&


From the disco website :

Conclusion: Best Performance, Short Life

Seems like you discovered that.

Re the pads and when they work. For road bikes, you really need a pad that works well at both ends of the spectrum. One that does not have any initial bite is no good, especially if you commute as well, and there can also be long sections of no braking and suddenly, you need some !!!

During a recent descent down the aforementioned climb (Mt Osmond - Beaumont side), at the bottom (the last section is through suburbia and is 9% for the last 900m where you have to constantly brake as there are MANY driveways) I decided to see how hot the system was.

The caliper body was pretty warm (didn't burn, but was uncomfortable), the disc friction face was discoloured, so knew that was toasty, the rotor support arms were similar to the caliper body, and finally, the pad backing plate was damn hot.

What this highlighted to me was that the finned pads from Shimano are a good idea. Anything that helps reject heat from a friction system is good. Period. It wont make bugger all difference 90% of the time, but I'll take that as a side issue compared to the 10% that WILL make a difference.

Which is also why I run a 180mm rotor on the front. Despite what Shimano say.

Nobody
Posts: 8553
Joined: Thu Sep 18, 2008 12:10 pm
Location: Sydney

Re: Massive brake fade

Postby Nobody » Wed Dec 10, 2014 3:49 pm

Edit: Not relevant.
Last edited by Nobody on Wed Dec 10, 2014 6:08 pm, edited 1 time in total.

User avatar
Dragster1
Posts: 1540
Joined: Mon Jul 08, 2013 9:46 pm
Location: Eluding motorist

Re: Massive brake fade

Postby Dragster1 » Wed Dec 10, 2014 5:08 pm

I would go for a rotor with a lot less holes and more of a sweep area or bigger diameter. No mater what brake pad you use if you go harder compound its going to make more heat and cook your rotor and pads. Once you over heat the rotor and it gets that black coating on it you reduce the braking friction and its all down hill from there.

human909
Posts: 8304
Joined: Tue Dec 01, 2009 11:48 am

Re: Massive brake fade

Postby human909 » Wed Dec 10, 2014 10:03 pm

Dragster1 wrote:No mater what brake pad you use if you go harder compound its going to make more heat and cook your rotor and pads.

How do you figure that?

If you are stopping at the same rate in the same conditions then you will end up with the same power and the same total energy/heat put into the rotor and pads. Basic physics, conservation of energy. (Of course some pads are less conductive and so will insulate the caliper from the heat build up better.)

You either need a bigger and cooler rotor & pad system OR have a higher temperature brake compound.

User avatar
Dragster1
Posts: 1540
Joined: Mon Jul 08, 2013 9:46 pm
Location: Eluding motorist

Re: Massive brake fade

Postby Dragster1 » Wed Dec 10, 2014 10:40 pm

human909 wrote:
Dragster1 wrote:No mater what brake pad you use if you go harder compound its going to make more heat and cook your rotor and pads.

How do you figure that?

If you are stopping at the same rate in the same conditions then you will end up with the same power and the same total energy/heat put into the rotor and pads. Basic physics, conservation of energy. (Of course some pads are less conductive and so will insulate the caliper from the heat build up better.)

You either need a bigger and cooler rotor & pad system OR have a higher temperature brake compound.

In the OPs case the rotor is black already pretty overheated to me, go to the next level harder pad compound, the rotors will fry even more. He has had brake failure from the brake set up he has now it cant get rid of the heat fast enough. Going to harder pads will generate even more heat as he will most likely be able to brake harder and longer. Im 75kg and run a 185mm avid disc brake on my mtb and use metallic brake pads and I am able to fry them at my weight and I cant image a largely slotted light weight 165mm rotor doing well with close to a100kg rider on board braking hard. On my road bike I run a 160mm tektro disc that is thicker and has a larger sweep area to the Avid disc I have on the mtb and I do quite a few mountain descents at 80kms and only brake in a few spots but they seem to hold up. I have over 20 years of experience on working with brakes and partly on race cars at that and I wouldnt recommend he goes to a bigger diameter rotor on the front which would be the best solution but it will rub like mad when he corners it's typical of light weight carbon forks from my experience.

User avatar
RonK
Posts: 9801
Joined: Mon Aug 24, 2009 2:08 pm
Location: Brisbane, Queensland
Contact:

Massive brake fade

Postby RonK » Wed Dec 10, 2014 10:53 pm

Jeez - brake fade, overheated discs, melted pads, noise. What happened to disc brakes being the answer to all our braking problems (that many didn't even know they had)?
Cycle touring blog and tour journals: whispering wheels...

User avatar
Nate
Posts: 3149
Joined: Mon Oct 20, 2008 8:49 pm
Contact:

Re: Massive brake fade

Postby Nate » Wed Dec 10, 2014 11:30 pm

The rotor isnt cooked - the black stuff comes off easily with some acetone, its not metal discolouration from heating - more melted pad (not pad dust).
looks like they're NOT G2 clean squeaks.

Kevlar tomorrow & see how we go.
Is heat in a mechanical caliper a massive issue? (obviously for metal component failure yes - but its not boiling fluid without fluid!)

Manufacturer happy to replace with 3 sets of a compound of my choice... i just need to know what compound will work!

hmmm might look at 160-180 rotor upgrade...

User avatar
Dragster1
Posts: 1540
Joined: Mon Jul 08, 2013 9:46 pm
Location: Eluding motorist

Re: Massive brake fade

Postby Dragster1 » Wed Dec 10, 2014 11:34 pm

RonK wrote:Jeez - brake fade, overheated discs, melted pads, noise. What happened to disc brakes being the answer to all our braking problems (that many didn't even know they had)?

yeah I know! light weight road bikes and disc brakes just don't seem to go well together in my eyes and I still hold my thoughts of rim brakes highly.

User avatar
Mulger bill
Super Mod
Super Mod
Posts: 28921
Joined: Sun Sep 24, 2006 2:41 pm
Location: Sunbury Vic

Re: Massive brake fade

Postby Mulger bill » Wed Dec 10, 2014 11:40 pm

RonK wrote:Jeez - brake fade, overheated discs, melted pads, noise. What happened to disc brakes being the answer to all our braking problems (that many didn't even know they had)?

They bite hard and quickly in the wet, that's the answer I was searching for :wink:
...whatever the road rules, self-preservation is the absolute priority for a cyclist when mixing it with motorised traffic.
London Boy 29/12/2011

User avatar
Dragster1
Posts: 1540
Joined: Mon Jul 08, 2013 9:46 pm
Location: Eluding motorist

Re: Massive brake fade

Postby Dragster1 » Wed Dec 10, 2014 11:46 pm

Nate wrote:The rotor isnt cooked - the black stuff comes off easily with some acetone, its not metal discolouration from heating - more melted pad (not pad dust).
looks like they're NOT G2 clean squeaks.

Kevlar tomorrow & see how we go.
Is heat in a mechanical caliper a massive issue? (obviously for metal component failure yes - but its not boiling fluid without fluid!)

Manufacturer happy to replace with 3 sets of a compound of my choice... i just need to know what compound will work!

hmmm might look at 160-180 rotor upgrade...

The first photo is deceiving looks black with scrape marks in it but your brake pads are absolutely fried. See how you go Ive never played with Kevlar pads, on the rear of my mtb I wanted to keep with 160 and went to the avid HSX rotor it was a little better than the HS1 I had on it. The HS1 would get really hot easily and then would start to squeal like a pig with organic pads.
Last edited by Dragster1 on Wed Dec 10, 2014 11:59 pm, edited 1 time in total.

User avatar
Dragster1
Posts: 1540
Joined: Mon Jul 08, 2013 9:46 pm
Location: Eluding motorist

Re: Massive brake fade

Postby Dragster1 » Wed Dec 10, 2014 11:51 pm

Mulger bill wrote:
RonK wrote:Jeez - brake fade, overheated discs, melted pads, noise. What happened to disc brakes being the answer to all our braking problems (that many didn't even know they had)?

They bite hard and quickly in the wet, that's the answer I was searching for :wink:

Whats wrong with the pre brake swipe action plan. :wink:

User avatar
Nate
Posts: 3149
Joined: Mon Oct 20, 2008 8:49 pm
Contact:

Re: Massive brake fade

Postby Nate » Wed Dec 10, 2014 11:52 pm

commuting in all weather in Sydney traffic = Disc only.
Rim brakes = forget it.

looking at the forks:
Image

There appears to be a 180 to 160 adapter already on there?!?
So i should be good for 180's up front

If thats the case then i'll do a 180 upgrade for sure, i dont need to stop harder all the time - but just give a bit more headroom & reduce heat stresses on everything

User avatar
Drizt
Posts: 1051
Joined: Sat May 10, 2014 9:51 am

Re: Massive brake fade

Postby Drizt » Wed Dec 10, 2014 11:54 pm

Are these issues mechanical disc related? Haven't had any such issues with r785 hydro. I'm using the stock pads. Done plenty of 80km/h decents with some hard braking

Nobody
Posts: 8553
Joined: Thu Sep 18, 2008 12:10 pm
Location: Sydney

Re: Massive brake fade

Postby Nobody » Thu Dec 11, 2014 12:05 am

RonK wrote:Jeez - brake fade, overheated discs, melted pads, noise. What happened to disc brakes being the answer to all our braking problems (that many didn't even know they had)?
From what I've read of reviews, although road bike caliper brakes have improved with direct mount versions, hydro discs are still better. Whether that is good enough to overcome the extra weight, aero drag, cost (depending on system) etc is up to the individual to decide. If I was racing in dry conditions, then I'd prefer caliper brakes. In almost all other situations, discs are likely to be safer and outperform road caliper brakes.

User avatar
Nate
Posts: 3149
Joined: Mon Oct 20, 2008 8:49 pm
Contact:

Re: Massive brake fade

Postby Nate » Thu Dec 11, 2014 12:06 am

Drizt wrote:Are these issues mechanical disc related? Haven't had any such issues with r785 hydro. I'm using the stock pads. Done plenty of 80km/h decents with some hard braking


read original post...
had stock caliper & disc without issues... not mech related.

User avatar
Drizt
Posts: 1051
Joined: Sat May 10, 2014 9:51 am

Re: Massive brake fade

Postby Drizt » Thu Dec 11, 2014 12:07 am

So... Um... Use the stock units...

User avatar
Dragster1
Posts: 1540
Joined: Mon Jul 08, 2013 9:46 pm
Location: Eluding motorist

Re: Massive brake fade

Postby Dragster1 » Thu Dec 11, 2014 12:11 am

Drizt wrote:Are these issues mechanical disc related? Haven't had any such issues with r785 hydro. I'm using the stock pads. Done plenty of 80km/h decents with some hard braking

Whats your rider weight and rotor set up ( Ice techs) ? Im running Hydros

User avatar
Drizt
Posts: 1051
Joined: Sat May 10, 2014 9:51 am

Re: Massive brake fade

Postby Drizt » Thu Dec 11, 2014 12:13 am

Me plus bike is 100kg approx. Ice technology rotors (forget model) 160mm front and rear

jackthelad
Posts: 240
Joined: Sat Nov 15, 2008 12:24 pm
Location: Perth, Western Australia

Re: Massive brake fade

Postby jackthelad » Thu Dec 11, 2014 12:38 am

you do know that you shouldnt clean the discs?
maybe once a year, if that with isopropyl or spray can disc brake cleaner on a rag
i run avid elixers and bb7, all still on original pads, sintered ...
hardtail with panniers, commuting
and 2 duallies offroad, braking in pea gravel
all on original discs roundagon and G2's
a few issues i can see is non avid discs etc etc for avid brakes use...
the brakes are designed to run on the hardened steel of the manufacturers choice..
the only thing that is the different is the hydraluic versus cable
and pad choice
Shitmano i have no clue on
SantaCruz HighTower LT
SantaCruz Blur XC Carbon
Kona Kula Supreme
Ribble Rd Bike

Who is online

Users browsing this forum: No registered users