Disc brakes and bike washing

[Steve vRS]

My Ultegra disc brakes are often terribly noisy. I must be contaminating them with something but I am very careful with oils etc. near them.

Then it occurred, I wash the bike with Meguirs car shampoo. It has waxing agents in it. Could this be the cause of my brake squeal?

[Dannbodge]

Yes more than likely.

[Alicat]

I always clean discs with brake disc cleaner after cleaning the bike.

[bobbo89]

Sounds like you've found what you're doing wrong.

I've been riding bikes for years and disc brakes have always been very sensitive to contamination of any sort to the point that I'm paranoid AF about it. Get some disc brake cleaner on your pads and rotors then take a micron of material off your pads with a metal file to make sure, always worked for me.

[Steve vRS]

Bugger. It did make the frame nice and shiny though!

[Caddyshack]

Use brake cleaner and some wet n dry paper to clean them up, I would use something like 800 or 1000 and see what that does.

[bobbo89]

Yeah you've got to be pretty careful. Most common problem people have is when cleaning their bike they use a hose a pressure washer and when cleaning the rear mech and cassette they blast their rear brake rotor and pads with watered down chain lube.

[summit7]

I tie a plastic carrier bag over each disc before washing, I have not had any disc issues with this method.

[GravelBen]

Before going to the trouble of cleaning/sanding rotors and pads etc, try a few hard stops to get the brakes good and hot. Sometime that is enough to burn off residue on the brakes.

My MTB brakes are often very noisy and squealy after being carried on a car rack on a wet road, can't really avoid the road grime/spray getting everywhere. But they quieten down after a couple of decent stops to warm them up and clean the surfaces off.

[Simes205]

A few hard stops and they clean themselves up!

[Steve vRS]

So how come my car brakes don’t squeal! It’s bloody bikes. They are designed to make us go mad.

[untakenname]

Some IPA or brake cleaner on a microfibre cloth is worth doing after cleaning the bike, or even if not cleaning the bike but have used it in the wet, especially on the rear rotor.

[stargazer30]

I never understood the logic here. My disks squeal only when wet and I don’t take any serious precautions washing the bike. I even use WD40 to degrease the chain. It seems a nonsense trying to keep the disks perfectly clean when they get covered in god knows what during use - Mud, poop, oil, grit, salt, sand etc…. This is a gravel bike mind, it rarely comes back clean.

[benny.c]

I jet wash my MTB all over, no attention really paid to what’s going where. Immediately after cleaning I wipe it down and blow compressed air lightly in hard to reach places - mech, callipers, shifter etc. Then a quick ride for a minute with a few heavy stops. Works for me.

Edited by benny.c on Thursday 8th February 19:22

[Miocene]

I also have Ultegra discs with the same problem! Awful noise when coming to a stop - slowing down is fine, but the stop is awful.

I've taken them off, used copious amounts of disc brake cleaner, iso alcohol, set them on fire (seriously, meant to burn off contaminants) and replaced the pads.

Same crap problem.

I just put up with it now, but mainly because I don't have to do a lot of braking on the routes I take.

[GravelBen]

Steve vRS said:

So how come my car brakes don’t squeal! It’s bloody bikes. They are designed to make us go mad.

Bike rotors are skinny flexible things that resonate easily. Car rotors are much thicker more solid lumps of metal that don't resonate as much.

Science!

[Steve vRS]

GravelBen said:

Steve vRS said:

So how come my car brakes don’t squeal! It’s bloody bikes. They are designed to make us go mad.

Bike rotors are skinny flexible things that resonate easily. Car rotors are much thicker more solid lumps of metal that don't resonate as much.

Science!

I suppose car brakes get a bit hotter as well which may be a factor.

[Fluffsri]

Another cause for noise is poor alignment, make sure that the caliper is square to the disc. I tried everything for a while when I bought a new Orange, I cleaned, aligned and sanded, different pads etc. In the end someone told me to flip my discs and run them the opposite way, got rid of all noise.

[gp1699]

Shower caps from hotels make for good disc protectors when cleaning/lubing.

[andyeds1234]

Strange one this, brake contamination is obviously a thing, but I’ve never had an issue, unless pads or rotors were damaged, where a few hard braking cycles didn’t get rid of any squealing, or dirt on pads and rotors.
I have never taken any particular care when washing bikes or drying them afterwards, so I’m not really sure what causes the issue.