motorthings

Somewhat SRAM-specific (at least for the caliper rebuild kit part number):

I learned that new rotors will squeal for a while until some of the pad material is deposited on the rotor.
There are a few sites i found that give good breaking in procedures for new pads/rotors, so i won't get into that here.

I had squeal pretty bad for a long time from my SRAM Rival Hydraulic calipers, and a lot of it was caused by two things:
1. pads not being centered on the rotor (esp when changing wheels)
2. one piston not fully retracting in the caliper.
3. rotors needing to be trued

the things i tried with some effect:
1. ran brake pads over 200 grit sandpaper (crosswise to direction of rotor rotation) to get any grooves out
2. advanced the pistons and cleaned them based on the method shown in the park tools videos
https://www.pinkbike.com/news/tech-t...ol--video.html
3. trued my rotors

All of this helped, with the piston advance helping the most, but what I ran into was that the piston/seal on one side of each of my rival calipers was not allowing that piston to retract as it should, so they would start squealing again after one or two rides. I took my bike to the shop (since I have a toddler and newborn, i was lacking the time, but not the inclination to do it myself). I asked the shop to order the seal and piston rebuild kit for the calipers and replace them and rebuild them, then bleed them. SRAM Hydraulic Road Disc Piston and Seal Kit B1 - SRAM kit part number 11.5018.029.000

That work fixed everything, but when I switch wheelsets I make sure to adjust the calipers with this tool: https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
I loosen the caliper mount bolts a bit so they can move, slide the feeler gauge parts of the hayes tool so one is on each side of the rotor, between the pad and the rotor, then hold and release the brake lever a few times, holding it on the last time as i tighten the caliper mounting bolts. This makes sure the caliper and pads are centered on the rotor, with an equal gap on each side.

The first few times swapping wheels took 5-10 minutes, but now that I know how to use the tools and the process, I can swap wheels and align everything much more quickly.

There you have it, my long-winded solution to getting rid of the squeal.

FlashBazbo

(Or . . . you could have bought Shimano in the first place.)

Roger Ramjet

I purchased a bike last year with SRAM hydraulic disc brakes and also had problems with them. My problem was not squeal, though, mine was that the front brake was dragging, and continued to drag, no matter how far I rode or how much or little I used the brakes.

The shop (one item at a time) replaced the rotor, the pads, and finally, the whole caliper. It never completely fixed the problem, although it is much better. But I find that from time to time on a ride, the front brake will still drag. Although, now, it will go away. And after I use the brakes, it may come back.

No more bikes with SRAM hydraulic disc brakes for me. I now have one with Shimano hydraulic discs, and they never act up.

DrIsotope

I never knew that folks has issues with SRAM hydro calipers-- I never really did my due diligence when I impulse bought a set of Rival 1 HRD levers. I only learned then that they used DOT fluid.

Like the lady at the office who wins the football pool because she picks the cutest uniforms, I bought Hope RX4-SR calipers because they looked amazing. They stop even better. Every bike needs 4 piston brakes, right?

And while I've only had them on the bike for about 1,300 miles, they have not been touched once since I installed them. No squeaks, no honks, no howls. Well, the rear rotor makes a tittery bird-like chirping under soft braking, but it's definitely something on the rotor, because the front is absolutely silent. I did not install new rotors when the new calipers went on, so the rear rotor has almost 10,000 miles on it. That might contribute.

unterhausen

Shimano had a quiet recall of their brake pads for squealing a couple of years ago. Not sure it's still in effect I got my brake pads replaced that way. I'm sure there are just as many squealing Shimanos as any other brand. If I didn't ride my MTB for a week, it would squeal like crazy and then (usually, not always) fade away sometime during a ride. Going on group rides with the bike shop owner was helpful, the squeal was embarrassing him.

Cyclist0108

I did not know that. At one point I had a hoard of about 12 pairs of F01A pads that I had worn through. Maybe I could have warrantied all of them. Was the recall at the time when they introduce the J02A pads?

motorthings

I figured this post would get at least one comment like that...i've never been a brand-ist or anti-brand-ist, but it seems there are just as many complaints about Shimano brake squealing out there on the internets are there are about SRAM. It is tough to accurately quantify it, so I'll just be happy that I have learned skills that will help me with any brand i use in the future.

I was looking at the Hope calipers recently, but i was following the experiences below and it sounded like a mixed bag
https://weightweenies.starbike.com/f...p?f=3&t=146254

I guess SRAM, Shimano, Hope, etc, all have problems sometimes, and the law of adverse selection means we only see the complaints on the webs (except where the people with positive experiences with a different brand jump in on those threads to try to make you feel silly for not having their bike)?

trailangel

Why does one need those 4 piston brakes again?
It's a bicycle, right?

Abe_Froman

Shimano is finnicky too.

I've got hydro 105 brakes as of a month or 2 ago. back wheel would rub ever so slightly. I tried adjusting the caliper...retracting the pistons. Eventually figured out the rotor was ever so slightly warped. Like on the order of 0.25mm. Just enough to rub one spot ever revolution, and be able to tell. If the bike is on the workstand. And I'm looking right at the rotor from 3" away. I'm a bit neurotic about it

So I got the rear fixed. And then the front started doing the same thing lol

Looks like the bearings broke in and loosened up just ever so slightly, enough where I can feel a wee bit of play if I push the wheel side to side. So now I have to order cone wrenches big enough to go around the thru axle. I'd be annoyed if I didn't like working on bikes

Secret Squirrel

Went from new Magura rotors to new Shimano rotors on Ultegra Disc. Squeal went away, but rotors are rubbing slightly. Can't win.

motorthings

i think you are right, with any set of components (esp. if you are not swapping wheels), you may get lucky with a good setup and have everything work well for a long time.

i'm used to motorcycle brakes, where the mass of the rotor, length of piston travel, and any runout is enough to easily kick the pads off enough to avoid noise, but on a bike, the stiction of the seals can easily be too much for the slight runout of light rotors to overcome. the result is a much more finicky setup regardless of brand.

DrIsotope

I went through that whole thread, and it didn't really seem like anything outside of the typical problems nearly every product has at early release-- a stuck piston here or there. I have had absolutely zero issue with mine. They even re-center when putting a wheel back in (I'm on QRs and cheap hubs) or swapping wheelsets, an action which invariably had be fiddling with the calipers on my old brakes. I do agree that at times they seem almost too powerful. With slick-centered Overides on dirt, I often lock up the rear wheel without much hand pressure on the lever. I'm still getting used to it. It is weird to be able to brake from speed to a complete stop using just the rear brake.

Want > Need.

They are very pretty, and very well made. So pretty I don't even mind the horrible Easter Island Head-looking SRAM Rival Hydro levers.

motorthings

Agreed, i was hoping for some updates, but as so often happens, the o.p. never comes back to say that they got things working out ok (even though they likely did), so I am left wondering. Do they not know I need their reassurances?

DrIsotope

I kid you not-- when researching a future purchase, I have many times thought the exact same thing. It might be from a few years ago, and the thread's last or nearly last post is something like, "I'll keep you updated with the progress/outcome/etc," and that's it. Thread just ends. Did the product kill that guy? What happened!?

Not as bad as the 2 or 3 star review based on slow shipping time, but still.

motorthings

people are just no darn good, i tell ya!

Cyclist0108

Not sure I would consider that an asset.

But you are getting almost 4 times the mileage from your rotors as I am, so we probably use our brakes differently.

DrIsotope

Well, only on dirt, on a Happy Medium style tire. I had a whole lot more miles (like 30 times as much) on mechs and semi-hydro, so my hands still want to apply that amount of pressure.

I don't think I can fault a brake for doing it's job too well.

gus6464

SRAM hydro brakes are poo. I have taken brand new cheap Shimano deore's out of a box and on a bike with very little knowledge on installation and no squealing. That's not happening with sram brakes. Shimano just needs to release a 1x road group so all the gravel bikes with garbage brakes can go away.

I have taken in my Slate to get the apex hrd brakes adjusted 3 times since march because of squeal or rubbing. LBS will adjust it and it always ends up coming back. Pure poo.

motorthings

sounds like either they or your shop mechs are poo.

if it only takes a sample size of 1 to determine poo-iness, then they are all poo.

redlude97

I think you've hit on the main points. Pistons dragging and not retracting is the #1 issue with keeping a system from rubbing and/or squeeking. After lots of tuning I've pretty much got it down to a science like you seem to have figured out. I'll also add learning to true a rotor is very helpful skill that many people can't seem to master. I've got 2 QR disc bikes(cannondale caadx/superx) that have a shimano rs685/685 system with resin brake pads and a Sram Red HRD with sintered pads and I can swap the wheels back and forth(4 total wheelsets) without issue.

motorthings

i did a decent eyeball true on my rotors, but need to make a block that bolts on at the caliper mount and allows me to slip a dial indicator through. then i can get down to .01 gnat's ass runout instead of the .99 gnat's ass they are at now.

redlude97

I've never had in issue as long as I eyeball the rotor inbetween the pads with a good light source, they don't have to be perfect to prevent squeel, that usually is the result of significant deflection that applies uneven pressure like older single piston mechanical designs(BB7 etc)

RedBullFiXX

Have a bike with SRAM Red HRD, and a CX bike with SRAM Force Hydro
No squeals or rubbing

Perhaps there are much more SRAM Disc out there, so the complaints are skewed ?
Have friends with Shimano disc as well, certainly not more rosy on that side of the fence

Zaskar

Full disclosure: I think Shimano bike parts are worthy of a Nobel Technology Prize. Their shifters, derailleurs, brakes... just awesome stuff. But, I decided to be open minded when I bought a mtn bike - full SRAM group. The shifting is $*@&ing great! The brakes - SRAM XX... just absolutely sucked. They squealed, chattered, were hard to modulate, felt like metal on lumpy metal. The shop tried new pads. Nope. They polished/sanded/cleaned the rotors. Nope. They used spacers to change the angle of the caliper. Nope. Eventually, the shop GM said "How about we swap over to Shimano. These suck."

The new Shimano brakes were perfect... as expected. I've heard people say they like their SRAM brakes. I've also heard people say their Land Rover is dependable.

Because Shimano exists, I don't see the need to play with SRAM.

ridelikeaturtle

Having never had disc brakes on a bicycle, this might be a dumb question: is smearing copper grease onto the back of the pads, where they contact the caliper piston, a possible solution? It works to eliminate brakes squealing on cars and motorbikes.