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Road disc brake problems
I need some help with my disc brakes!
I am having a lot of problems with contamination of pads/rotors. Not really sure why but i now have two noise and vibration devices rather than brakes. The brakes are RS805's from last year.
Last night i sanded all the crap off the rotors. Got them nice and shiny. Sanded the pads (they are the standard shimano ones that come with the brakes). Got them quite shiny. Cleaned everything with isopropyl alcohol (again). All went bad when i cycled to work.
Fixing the rotors is easy; just need sandpaper and elbow grease. But the pads are more of a problem.
I have seen on some forums that people heat their pads to clean them. Anyone got any tips on this - how to do it? what temp to use? Does it work?
Dont want to buy more pads if i can help it. Last lot are only a few months old.
Never had a single problem with my MTB discs but the road ones are turning out to be a pain.
SAB
If you're new please join in and if you have questions pop them below and the forum regulars will answer as best we can.
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49 comments
I would tentatively agree, but as a regular contributor to 'discs are bad, hmm'kay?' type threads, my beef is not with the day to day maintenance, but with problem solving when things do go wrong, which in my recent experience they often have...
As this thread and several like it demonstrate, when discs DO misbehave, they can be an unholy, expensive, pain the ass to diagnose and fix.
I've now spent at least £100 trying to figure out and cure the awful noises emanating from my SRAM Level Ts on my 'fast commuter'. The solution? Spend another £150 replacing them with a totally different brake. I now have a complete set of SRAM brakes with several sets of pads and two sets of rotors that I cannot in good faith sell on to anyone as I just could not get them to shut up.
Since the industry seems intent on forcing discs upon us it seems like they should be more proactive in preventing and solving these problems, ultimately I'm sure my issue was due to either brakes with poor manufacturing tolerances, a frame with poor tolerances, or just a bad combination of brake and frame. Did the shop where I bought it care? Nope. Did Trek UK care? Nope. I could probably have kicked up a massive fuss and caused everyone a massive headache, but it just seemed easier to fork out for new brakes. More fool me perhaps.
Anyone seen or heard anything from Shimano to address the known issue of leaking callipers across all ranges and models? Nope. Seems easier for them to deal with the percentage of warranty returns and let the rest of us go through all the faff described in the posts above...
Rim brakes?
After a year of working brilliantly, my brakes somehow both got badly contaminated and were incredibly noisy and ineffective. I could resolve the problem temporarily by getting the brakes hot, and they'd then be fine for the rest of the ride, but the problem would return on the next ride.
I've now tried taking the pads out and heating them to 250c for about 5 min using a heat gun and cleaned the rotors and this seems to have pretty much sorted it.
I've read about the o ring issue on shimano calipers, but I'm sceptical that this is the problem here as the problem started with both brakes at exactly the same time and using the brakes seems to improve things rather than make it worse whereas I'd expect an o ring leak to get worse with use.
I've been running hydraulic road discs (R785) for nearly 3 years now on my main road bike and had very little trouble. I did have contamination problems early on due to liberal use of cleaning products and GT85 and had to change a set of pads. But since backing off with the sprays it's been fine. I do use a waxy chain lube (Squirt) in the summer so no excess oil flying about
I sometimes give the discs a clean with Muc-Off Disc Brake cleaner if I've been out in the wet and they get a bit squealy (not needed it all summer).
I can't see why anyone would need to sand a disc. It will never need anymore than cleaning with a decent solvent. It's impossible for oil or other contaminates to penetrate into the stainless steel. You can sand the pads if they've only got light contamination but if it's bad then just chuck them away.
Seems like the component shops mentioned in this thread dont have pads for RS805 brakes. Disco brakes dont seem to have any road ones. Uberbike have RS785 and RS685 but not mine. Wonder why? The brakes arent new.
Well, after a lot of deliberation I'm actually sitting in today waiting for my new Cervélo S3 disc to arrive. After reading the comments at least if things go wrong (as I seem to have a knack for) I've got a tonne of great advice to get me back on the road!
Daily issue here in the workshop for Road Bikes on Discs..... not going to say Told you So....lol. We are fairly flat in these parts so disc brakes never get used hard and the way they were designed to so the contaminents from the bike, other roads users and weather never get "burned" off. For me it's new pads all the time and keerrrchiiing in the till.... I guess it depends where you live, hilly areas will be best for disc brakes as they will be used the way they should be but for commuting and in traffic... then you will get contaminated... Clean the pad material as much as you like with any of the suggested methods... but in the end you will be fitting new pads
It was in my workshop too; I too will try to resist the "I told you so". The braking may be good, but the daily living with them is much more onerous. A road bike to me should be a thing of quiet beauty, which is not easily compatible with discs, either aesthetically or aurally.
I would hazard a guess that bicycle workshops perform many routine maintenance tasks and basic repairs that would be well within the abilities of most people if they could be bothered. Disc brakes are going to need maintenance just like any other component, or are you claming that your workshops have never been required to service, repair or replace rim brakes or blocks?
I serviced lots of things on lots of bikes for lots of people who could and some who could not have done it themselves!
I repaired whatever was brought to me and repaired whatever it was they wanted me to repair. Rim brakes had issues, mostly poor initial setup and pad placement, but it would be a very rare occasion that you couldn't just clean any oil contamination off a rim pad with some IPA, and a rim rubber on the rim restored those pretty easily. Disc pads, once contaminated, never came back to life very reliabley.
Contamination on rear rotors happens quite easily when someone over-lubes a chain. Check your rims out and notice the little specs of mucky oil that accumulate on a reasonably maintained chain, so imagine that on someone who just puts some more oil on whithout fully cleaning the old off, that's just one example of how oil is flying about near your rotors. These are the people who bring bikes to bike shops for service, not everyone is interested in the bike as a cyclist, many just like riding and the bike is a necessary component rather than the centre of their universe (weird, I know!).
Discs on MTBs seem much less prone to these issues, I think the gritty grinding paste that ends up all over them tends to rub off a lot of issues as it goes. The amount of oil and diesel deposits on our roads, especially town centre roads, means that much of this gets flicked up onto road discs especially when it rains.
As I said before, I'm no fan of road discs, but that is purely on an aesthetic basis, they clearly do work, but so did a decent set of dual pivot calipers. The difference is that calipers are very easy to maintain, with few issues, whereas discs can have lots of issues from contamination, to air ingress, leaky seals, alignment etc, so do require more care and attention. That is fine as long as you are happy and capable of doing it, in a workshop you see the people who are either not capable or don't have the time or inclination, that's my story anyway.
Disc brakes need no more maintenance than any other brake system. I have now had a set of Shimano XT disc brakes on my MTB for over seven years. I have used the MTB in all conditions both on and off road, as a commuter in the city and as a touring bike - I've used it for everything. I have never had an issue with contamination. The hoses, calipers, seals, pistons and even the fluid are all original. I have only ever replaced pads as they wear out. High maintenance? Bullshit.
I'll happily bow to your vastly broader range of experience than mine...
The best comment on disc brakes I've read on here, totally agree.
A moot point when I'm riding it.
Maybe Bristol's hilly enough for it not to be an issue for me, but commuting and riding on filthy city streets is much more of a problem for my rim brake bikes than for those with discs. I use (maybe wrongly) a different style of braking using discs as well, later and harder, whereas I feather rim brakes a lot more on descents.
You'd be against non-disc carbon rims then? Noisy in the dry, useless in the wet.
I was having trouble with my brakes squealing and rubbing until I lost patience and bought hope calipers. Trouble free ever since
http://www.hopetech.com/product/rx4-caliper/
And they look awesome in purple.
Loving my 90s revival in anodized purple.
Are you convinced contamination from the road is a real world problem? Anecdotally I've never had that problem in 2 years of city centre commuting on my disc bike, only time I contaminated them was after lubing sticky pistons with mineral oil on my hy-rds*. Would have thought it was that sort of thing and getting GT85 everywhere that is the issue.
*Themselves a bit of a bastard and I was only stopped from taking them into a shop to address lever travel issues by pure stubourness!
Guys, I'm actually amazed people are concerned about sanding the discs. This is a well established step in trying to solve contamination/squeeling issues.
Remember when they are supplied new in the box, they are not a 'polished machined surface' but a matt, buffed looking surface, which almost looks like someone has taken a fine sandpaper over it, funnily enough.
Obviously you shouldn't be taking a belt sander to them, and obviously you shouldn't be sanding away for hours and actively thinning the disc down, but I can tell you that for various reasons, I've had cause to sand discs numerous times, all you're doing is taking them back to the state they were in when brand new, so yes, you have to bed them back in again, but no, you're not leaving them more prone to contamination, no you're not weakening them, no you're not doing any permanent damage, etc. etc.
That said, you should be using wet+dry, not mega coarse sand paper, and you should probably be putting that file down...
Edit: re: prone to contimination, I guess if you sand the rotors but continue to use contaminated pads, then yes, you would be depositing contaminated material on the rotor. This step presumes using new pads...
that was my feeling about sanding too. Lots of people talk about it on the MTB forums. I think (with no real evidence) that it is fine to sand. It is the pads that are the problem to fix.
As mentioned above check that your pistons aren't sticking. Unfortunately if they are sticking and can't be freed then its time for replacement calipers, because as far as I'm aware Shimano don't sell spare pistons.
I don't know if this will help on disc brake rotors, but as a chippy, when our ciricular saw blades get 'contaminated' with resin etc from knotty wood, leaving them soaking overnight in oven cleaner works a treat, as nothing else (turps / meths / petrol) shifts that stuff. Might be worth a try. I'd be really wary (as mentioned before) of sanding the discs. They're a polished machined surface, and unless you're polishing with something like 4000+ grit wet and dry, then you're likely to leave a surface which is far more likely to become 'conatiminated' due to the small scratches retaining contaminant materials.
Hi SteeveB,
Everybody is talking about cleaning the pads. Have you tried to align the calipers?
1. Loose the mounting bolts so the brake can move around
2. Pull brake lever all the way (rather hard)
3. While you keep pulling, tighten the bolts again.
4. Release brake lever.
5. Rotor should be perfectly aligned now.
This more or less removed noise from my disc brakes.
I dont think there is a alignment calliper probem; there is no rubbing. I have aligned them in the past.
http://www.discobrakes.com/?s=0&t=0&
some great prices here and the quality is very good
thanks again for all the good input. Will throw the pads out. That is ~£40's worth. ouch. will try some of the cheaper ones suggested. if they get trashed it isnt so bad then.
i sanded the rotors as no way was the crap coming off with anything else. I tried isopropyl alchohol, muc off brake cleaner, jif, light sandpaper and then something coarser. It took some elbow grease to get rid of it. I saw sanding suggested on some mtb sites. seems to work okay but i hope i havent messed up the rotors.
cqexbesd - i will try your advice on checking for a leak on the front brake. it must be a really small amount coming out. Nothing drips on to the floor under the bike for sure.
The brakes seem much fussier than my MTB ones. I have cycled up to the axels in mud and never had a problem.
Rode in on my old bike today. Was too scary to have no brakes.
I would recommend Uberbike components for pads, not worth messing about, just change them out.
https://www.uberbikecomponents.com/category/324/Disc-Brake-Pads
I was going to say exactly the same and in fact their website looks very similar to Disco mentioned earlier, could they be connected ?
In all the years I've been using disk brakes (mountain bike and hybrid), I've never once taken sandpaper to the rotors or scrubbed a set of pads to the extent described above - I use Muc-Off and then car shampoo to wash the bikes and give the brakes a good wash with that at the same time.
I've used meths and brake cleaner a couple of times when I've serviced the calipers and cleaned the rotors.
When I've had squealing brakes, it's usually been down to a sticky piston meaning the pad on one side isn't releasing properly (rode my sister's bike from her house to my house with a howling front wheel because of this - it was a lot quieter when I rode it back!).
If you've got vibration, then it's also worth checking the hub bearings are ok - this is currently the problem on my mountain bike and will (kids permitting) be sorted this weekend.
Sounds like rim brakes aren't so bad after all
I have the same issue with mine. Part of the problem is material related. Car brake discs are made of grey iron which has an extremely high self-damping ability which is why they rarely make any noise. Bike rotors are made of stainless steel which has a much lower self-damping ability and so are very prone to screaching in the wet. Unfortunately, at bike rotor thicknesses, grey iron is too fragile to make rotors out of
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