Disc Brake Pad questions about different materials and makers
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BloomingCyclist
I have a question about pad material on replacements and would like information and advice about the different kinds of pad materials and brands. have a Winzip on a Santana and it uses pads compatible with Shimano mechanical systems. I have no idea who makes the brake pads but I could imagine that there aren't many actual manufacturers of pads. I have just installed new pads made by EBC (makes pads for disc brakes on cars, motorcycles, and bicycles).
http://www.ebcbrakes.com/
EBC makes a "green" cross-country / trekking grade for general use; a "red" high-friction soft compound for downhill race use only; and a "gold" high durability sintered metal compound - it says this pad should not be used for downhill racing unless system is originally fitted with them because of the risk of overheating.
My original pads wore rather dramatically on the 3 state 3 mountain ride and I am looking for some more durability. We're not downhill racing but wondered if that warning was for hydraulic systems (mine is mechanical) plus I don't understand how one kind of pad can generate more heat than another if they slow and stop the bike so... anyway, I installed the gold sintered metal pads yesterday and when we road, they stopped fine but made some noises (moaning / low pitched sounds) (my other pads never made any noise.) I would have also ordered some green pads but they weren't in stock. I did also get some Jagwire pads - red in color - for general use. I ordered both from aebike.com (alfred e bike)
For most of our riding, we really don't need the disc brake. We have hills but not long hills with multiple switchbacks or sharp turns. We felt we needed it for 3 state 3 mountain for the descent down Lookout Mtn and it is required to have a disc or drum for a ride down Mt. Haleakula next February on a Santana tour but I may reinstall our rear V-Brakes until then.
I'll admit that I'm not well-versed in disc brakes but I'm still trying to learn about them. We'll be in some mild rolling hills this weekend for the Horsey Hundred in Georgetown, KY north of Lexington so we probably won't be braking to much but we'll see how they do.
Bloomington, IN
The BikeForums Team
-adv-
This is an archived thread, you can find the full version of this thread, with images, links and more content here.
This one from Bryan B. that quotes another user's review of the EBC "Gold" is just too funny not to include: http://search.bikelist.org/getmsg.asp?Filename=tandem.10311.0563.eml
The only thing I would note about the EBC golds is that the extra metallic content that makes them bite harder and last longer also means that break-in time will be far longer than any stock "green" pads such as the OEM Avids, etc... Like all disc brake pads, until such time as the pads can firmly bed-in and align with the rotor they will not "bite" at full strength. The writer cited in Bryan B's post doesn't sound like he gave the EBCs a chance to bed-in. As for brake pad squeal, to some extent that too will disappear as the pads deposit material into the rotor UNLESS there is play somewhere in the brake hardware. I have to use CRC Disc Brake Quiet when installing our 4-pot Hope disc brake's pads to keep them from shattering glass and I suspect that the Winzip, like the Formula, may have some play in the caliper that also could also be a source for these small vibrations and "skip-slip" brake squeal.
http://us.st11.yimg.com/us.st.yimg.com/I/rodi_1947_88675193
I've used the EBCs on one of our off-road tandems, but have yet to mess with them on our road tandem's Avid BB: the OEM pads have been fine, albeit fading to nil on a descent off of Sand Mountain near Chattanooga, TN. I believe I previously attributed the Sand Mtn descent to Suck Creek Mountain in error. Suck Creek was a non-event compared to the other major descents around Chattanooga.
zonatandem
While discs seem to be the 'brake to have' they do present their own set of issues. Have never had our canti/V-brake pads fade/overheat/melt on any of our many mountain descents.
A pair of Scott-Matthauser pads on the rear of our old Assenmacher tandem lasted 'only' 50,000 miles.
cornucopia72
How often do you replace the Avid pads? How do you know it is time to replace them?
Thanks
TandemGeek
How often do you replace the Avid pads? How do you know it is time to replace them?
"How often" should vary from team to team, just as it does with rim brake pads. For example, heavier teams teams who routinely encounter descents that demand high or prolonged brake use would logically burn-through their pads far more rapidly than a lightweight team who live and ride in the flatlands. Zonatandem notes that he got 50,000 miles out of a set of brake pads, which even at 10,000 miles a year puts them beyond my threshold for replacement based on time, i.e., I find that most rim pad performance begins to degrade after about 2 - 3 years as the friction materials harden with age. Perhaps the Scott-Matthauser compounds aren't as succeptible aging: I haven't used SM pads since the 70's and can't recall if I even paid attention to such things back then. Linear-pull (aka V) brakes with their very thin pads are the only ones where I've had to replace the inserts due to wear vs. audible & tactile indications during brake use that the friction material was getting hard. So, again, "how often" is something that every team will need to establish by monitoring their disc brake pads for wear. As BloomingCyclist notes, a single tour or event with major descents that puts a high demand on the disc brake may do-in a set of brake pads: I've heard the same thing from some teams returning from Europe. Now, there was a problem early on with the Avids where a production lot was erroneously released with incredibly soft / fast wearing brake pads and folks were burning through those suckers in days and weeks, not months and years. Anyone who contacted Avid quickly received a set of proper replacement pads, but the Urban Legend regarding short disc brake pad life still lives on in some circles.
OK, so what are the replacement guidelines? Obviously, pads should be replace if they become contaminated or once visual inspection suggests the friction material is getting "thin". Per Avid's BB disc brake installation instructions (http://sram.com/_media/techdocs/bbdb-mtn-160-install.pdf), "A pad should be replaced when it’s total thickness (backing plate & friction material) is less than 3mm."[sic]
How does this translate into practical experience? We've had the Avid disc on our travel tandem as a full-time rear brake for 2 years and the pads still look good. That translates into about 4,000 miles of use since we alternate riding two different road tandems; however, the disc-equipped tandem is the one we use when we head to rides with steeper terrain. I tend to let our tandem run on descents and will only check speed before entering an unknown corner or when encountering traffic. However, I do use the heck out of it for most normal group ride conditions where a light feathering action is required as well as for routine stops. Of course, at 285lbs we're not high-demand brake users. Anyway, I'll have to measure to confirm just how much material is there compared to a set of new pads but, just eye-balling, it there appears to be less than 40% wear at the "lowest point" on the pads. By lowest point, it's noteworthy that on the Avid's the pads wear-in with a slight camber since the rotor is pushed a few mm off center and into the right-side pad when actuated. This is also why it takes a new Avid disc or new pads a little while to come up to full-braking power since not all of the pad material will initially be coming into contact with the rotor. Now, as you can deduce from my comments, I do keep a spare set of Avid brake pads in my tool box "just in case" just as I do with cables, inner tubes, tires, etc... I won't address off-road disc brake pads because, well, it's just not relevant to this discussion.
Other important guidelines included in Avid's instructions also address pre-ride inspections & cleaning:
Before each ride
- Check cables for signs of wear or fraying.
- Squeeze the brake lever firmly and check for proper brake function. Adjust for pad wear if necessary.
- Check pads for wear and replace if necessary.
- Make sure rotors are free of foreign substances and oils.
Care and cleaning
Extreme care must be taken when cleaning both the bicycle and
its new disc brakes. Under normal use, it is not necessary to
clean the caliper rotor or pads. If necessary, use only water and
dish detergent to wash the caliper and rotor - being sure to thoroughly
rinse all soap residue from the rotor. Dry with a clean
paper towel.
zonatandem
Scott/Matthauser pads were a very hard orange/red material and were incredable stoppers in their day.
When we running S/M pads back in the 70s and 80s, we were averaging 10,000 miles a year (our max was 13,000+ back in '84) and we used these pads exlusively.
They were great in all kinds of weather; on a Grand Canyon to Mexico Tour coming down the steep Mogollon Rim in heavy rain, we were outbraking a team on a tandem with cantis and a drum.
The newer stuff is good but not as good, in our opinion.
Braking technique also has a lot to do with how well you'll be slowing down.
stapfam
I ride with Hope Mono M4 brake units on the Tandem and these use the "Syntered" pad. This is the harder pad and although I have not used any other pads- The harder the pad- the less brake fade you will have when they get hot. They may cause the Disc to wear out faster but after 4 years of using the Hopes- around 10,000 miles, and 4 sets of pads (I change them as a matter of course before my big offroad ride each year) I can see no wear on the discs whatsoever.
Brian
We got less than 300km out of stock Avid pads when using custom titanium discs. There's a lesson to be learned there. Since switching to Shimano XT discs, we have had no noise and no fade. That's for a tandem team over the 300lb mark, and we used to ride in pretty hilly areas.
Heed the manufacturer's break-in directions.
RickinFl
Hey TG-
Marvin relates a rather funny story about riding with you and your wife on a recent Ididaride at White Springs, and trying to decide whose brakes were squealing worse- his or yours. It's a hoot to hear him tell it.
I just wanted to mention that the Magura Louise brakeset that Alex put on our Ventana is quiet. They will moan gently for a moment if the discs have gotten dusty, but that's about it. Marvin said he might change over to Louise brakes because the ones he has now are driving him nuts.
Rick
TandemGeek
... and trying to decide whose brakes were squealing worse- his or yours.
Hands-down, mine always win the glass-shattering contest.
FWIW, any story that Marv tells is usually a hoot. I'm not sure if he's just a great story teller or if he's just got funnier stories to share.
BloomingCyclist
If you haven't discovered them yet, here are couple of posts worth reading from the archives at Hobbes:
http://search.bikelist.org/getmsg.asp?Filename=tandem.10407.0108.eml
http://search.bikelist.org/getmsg.asp?Filename=tandem.10311.0554.eml
This one from Bryan B. that quotes another user's review of the EBC "Gold" is just too funny not to include: http://search.bikelist.org/getmsg.asp?Filename=tandem.10311.0563.eml...
We did our 100 mile Saturday and the 72 mile Sunday ride on the Horsey 100 with no great braking demands like Sand Mtn and Lookout Mtn but we did brake enough to see that the brakes felt good and we did a short 23 mile loop today after supper. Last week after installing, the EBC gold pads were noisy - loud low moaning noisy. When we got home from that initial test ride, I put the bike in a stand outside and turned the pedals while spraying water on the rotor with my wife applying the brake lightly. Besides throwing water on my patient and cooperative wife, I do believe that it did help "seat" the pads parallel to the rotor so on the 170 miles of riding this weekend it worked well and it isn't noisy except for a brief initial low rumble when I brake at a low speed. (Of course my front v-brake pads are starting to squeal - I think the toe-in has worn off.)
I didn't actually read the tandem@hobbes references from TandemGeek until tonight because of the weekend trip and staying at a motel with no internet access and coming back to final exams for my students and grading - but they are very informative posts - thanks Tandem Geek.
The author of the first two talked about working to get the correct amount of mechanical advantage. I too wish my lever was pulling a little more cable than it is with my brake power booster. I've thought about putting two in a row just to see what it would feel like but wondering if I would have the hand strength to really apply great pressure. I believe that some mountain bike (flat bar) levers have adjustable mechanical advantage - that would be a great thing. I have a friend with an Avid mechanical disk on his tandem (the mtb one - not the road one) with a brake power booster and I do think the lever feels very good (if he could just get the front derailleur to shift well - but that's his thread).
The post does make me feel like I am on the right track with the pads. One question I have which was mentioned in the third "funny" post was that the EBC gold was only for open systems because of high heat transfer. The language on the ones I bought don't talk about open systems but does say they are not for downhill racing because of too much heat and that they shouldn't be used on systems that don't use them as original equipment. I think the reference to open systems supports my thinking that the warning is for hydraulic systems only and it wouldn't matter for a mechanical system. Do those of you reading this agree with my thinking on that or is there something else here that I am ignoring at our peril.
Bloomington, IN
TandemGeek
Do those of you reading this agree with my thinking on that or is there something else here that I am ignoring at our peril.
Yes, Open vs. Closed refers to hydraulic disc brakes, e.g., the Hope Enduro's on our off-road tandem are a 4-pot hydraulic, Open System that uses a master cylinder with bladder to allow for heat-related fluid expansion and brake pad wear. Santana's hybrid mechanically activated hydrualic Formula disc brake was a Closed System that had a master cylinder but no bladder to allow for fluid expansion or the ability to compensate for brake pad wear. The Avid and WinZip mechanical disc brakes are functionally the same as a "Closed System" in that they use a fixed-stroke activation mechanism that won't automatically compensate for brake pad wear the way an open system will. Of course, since they use a cable vs. hydraulic fluid they aren't vulnerable to heat expansion.
As for your peril, the noise and gritty feeling transmitted via the brake system that accompanies outgassing and brake fade as a bicycle's disc brake begins to overheat will always be a fairly reliable indicator that you're approaching the limits of your brake system. The sintered pads will simply cause this to occur in less time under the same braking conditions. Therefore, if your descent has no end in sight and will not afford you the opportunity to alternate your braking to the front wheel to allow the rear brake to cool it's time to use that front brake and remaining stopping power from the rear to bring your tandem to a safe stop. One stopped you can allow those brakes to cool while you get the blood circulating in your hands. Imagine if you will, descending Burkhalter Gap instead of climbing it and trying to check your speed at 20 mph: you probably wouldn't make it out of the switchback section before your brakes were toast.
BloomingCyclist
I just wanted to update my own thread with a report on how the EBC gold pads (sintered metallic) have been working with the Winzip. I've been very pleased. I feel like I have excellent stopping power (more effective than I had felt with the original pads) and they are not making noise and they are not wearing. I have not tested them on an extremely long downhill like we had in Tennesse on the 3 State 3 Mtn ride so I can't give a performance comparison for that yet. I think I may also try the EBC green pads also but I haven't ordered them.