Hey everyone!
I just recently(about a month and a half ago) had new brakes fitted to a new hardtail I bought.
Brakes are Shimano Deore 6120 4 piston front and rear with finned Deore metallic pads(all brand new).
I needed bigger rotors as well so I replaced my 180/160 mm SLX rotors with Sram Centerline TC12SEP23 203mm rotors front and rear(again brand new).
I've been riding the bike about 4 times a week for about a month and a half mostly on tarmac and very occasionally on smoother trails, with the tarmac rides being sometimes up to 50 kilometres in a single ride – 6.39 km climb and then descent as fast as I can a few times.
Right now I ride my bike mainly as cardio to lose weight so I haven't done any proper trail or all-mountain runs.
I haven't used the brakes for very long hard descents with heavy braking like on an Enduro or DH run but I have had to use them for up to 1 km countinuously at lets say 50-60 % of their power to maintain a safe speed , so I doubt I've really managed to build up too much heat or anything to actually damage the pads or disc surface.
The photos at the top are from left to right rear brake first then front.
The one that really squeals bad is the rear with the front only making a little bit of noise which I don't think is a problem but I would still like to know what you guys think.
I haven't taken the pads out yet to check if they have been contaminated or damaged.
The mechanic who put everything together may have done something to the rear ones, like touching them or the discs with greased fingers but I haven't asked him yet as I'm out of town now and can't go back right now and I would have to bring the bike with me.
The first few rides the brakes made absolutely no noise but I was probably still bedding them in (even after braking for a total of 4 km) so I guess that's why.
What do you guys think from the photos?
Is there anything is should know/do before removing the pads?
by Far_Zucchini411
4 Comments
Pull the pads and check for oil on the back of them, could be a leaky piston.
The issue with contamination is unless you can literally see oil sitting on the pad backing plate it’s hard to see they’re contaminated. I’ve had brakes squeaking from contamination while looking visually perfect on more than a few occasions and the only way to be sure it’s fixed is just to replace pads and rotors.
Could be the mechanic touched the rotors. Could be a leaky piston. Could be poor bleed technique got oil on the pads. Could be the pad and rotor combo. Lots of people run organic pads specifically because they tend to be quieter.
Whipe the rotors with isopropyl alcohol. Never touch them with your hands they get contaminated easily. All brakes squeak to some extent. Resin pads are quieter than metallic.
There’s nothing abnormal from the photos. Did you bed them in properly or just ride? Do a search for the procedure. If not, you might just try that first. It that doesn’t work give the rotors and pads a little sanding and try again.
Mountain bike disk brakes are notorious for squealing. You can have two identical setups and one will squeal while the other one won’t.
If you’re not pushing it hard the easiest option is probably some organic brake pads. They tend to be more quiet but have lower performance in terms of power and heat resistance. They will also wear out faster, but again my experience has been that they’re silent.
I’ve personally had squealing with the centerline rotors also, I assume because they’re so thin, and it gets worse as they heat up. You know which ones don’t squeal? The cheap, thick, stamped Shimano rotors that come in lower end bikes – and they work fine for most riding.