I bought new Dura Ace rotors for a new wheel set. LBS built the wheels and swapped them over when I picked them up. The back rotor bedded perfectly, front one didn’t. For reference the callipers are 105 7170s and rotors are 160mm, same size as the original 105s.
I bought new pads (Shimano L05A-RF), reset the pistons with the old pads in place, removed old pads and cleaned everything with Silca brake cleaner. I gave the DA rotor a light sand, followed by a second round of cleaning.
Installed the new pads, aligned the callipers and once again, they haven’t bedded properly and are squealing.
I took out the pads and noticed the tapered wear, but it is on both pads. As far as I can tell the pads are covering the rotor correctly. It looks the same as the rear.
Anyone have any suggestions what is wrong? LBS is closed for the next week but I feel like this is something I should be able to do myself.
by notasabretooth
12 Comments
The taper is from factory, not wear.
If you’re sure your pads and rotors are clean and the alignment is good, just continue riding and bedding them in. They’ll stop squealing after a few dozen kilometers.
I stopped using Shimano brake pads in my 7170 calipers because of their persistent squealing. In the dry they were okay(-ish), but with only a hint of moisture it became a howlingfest.
I’m now using Bucklos (Aliexpress) “ceramic” brake pads and couldn’t be happier, both with their sound (virtually silent) and their braking performance (very smooth, controllable bite point).
(And yes, I know that some people will automatically downvote when they read “Aliexpress”, but I’ve been riding these pads for 1000’s of kms over the last 18 months or so, on multiple bikes, and I’ve never had any issues with them. Unlike the Shimano ones…)
Replace pads and rotors with Jagwire. Or Galfer or Swiss Stop. We use Jagwire at my shop. Works every time. For good measure, make sure there isn’t a leak.
Have you checked for sticky piston? Common on Shimano calipers, and the uneven pad pressure on the rotor can cause a squeal. I had this the other day, piston service fixed it
In my experience working in a bikeshop, some have brakesqueel some don’t. Kinda a 50/50 chance. If you do have it clean the rotors properly and burn off any contaminated material on it. Get swisstop pads and your usually done if not get new rotor’s
Make sure you’re using pads compatible with the rotors. My rotors are resin only, found that out the hard way. And if they still squeal try burn the rotors, it will remove any residue. Then put fresh pads on.
Spray brake cleaner on the pads, light them on fire. I’m not kidding.
Lightly sand the rotor with a piece of sandpaper. Pinch the rotor on both sides with the sandpaper while spinning the wheel to lightly scuff the surface of the rotor – just a few revolutions. Wouldn’t hurt to scuff the pads as well.
Why do they need to invent the wheel again with bicycle brakes? With cars it’s already known what to do. It’s the vibration which causes squeeling. Put a little, realy little drop of copper grease on the back plate and you are done. With cars it’s also the guides you have to grease with copper grease.
Just ride it for a few seconds, holding the levers in a half pulled position to make it howl as loud as possible, if you go 500m pedaling.into the half pulled brake it will burn away the dirt and set the pad. You will have to do.this everytime it howls.Yes resin shimano pads tend to howl.
News Pads on used disc?
You can try sand paper on the rotors/pads and then try breaking again.