Disc brakes work better when wet

GeX

GeX

GeX

Soldato
Joined
17 Dec 2002
Posts
6,924
Location
Manchester
I have Shimano SLX M675 disc brakes. After cleaning and then storing my bike, piston on my rear brake began sticking. I have since cleaned up, and it moves freely again. I bled the system and the brake seemed to work well again.

I went to use the bike the following day and noticed brake performance wasn't great so bled it again when I got home. I didn't test it.

Since then I've noticed that the brakes are much 'snappier' when wet. This is noticeable on the both brakes but more noticeable on the rear. If I apply a lot of braking force to the rear brake then it just squeals loudly, if I apply much less force but in the wet I can feel it braking and easily lock the wheel. Similar is seen with the front, but the braking performance when dry is still very good.

I am running metal rather than resin pads. Does it sound like the pads are not suitable, or the discs (or pads themselves) are contaminated. If so, how is best to clean them?

The bike is a MTB frame, but with road tyres (guess you call it a hybrid) and I use it mainly for on-road commuting.
 
It does sound like the pads are contaminated.

I've heard of "baking" the pads (or attacking them with a blow torch) to burn off the oil/contamination but it would probably be easier to just replace them.
 
Agreed on replacing the pads - it's so hard to get contamination cleaned out thoroughly.

You also need to very meticulously clean your rotors and surrounding area (and the calipers). Use a normal bike cleaner several times. Rinse, dry thoroughly and then use alcohol or a disc brake cleaning solution/spray. Dry again and then wipe with a pristine cloth.

Then replace your pads, not before.
 
Irish_Tom said:
It does sound like the pads are contaminated.

I've heard of "baking" the pads (or attacking them with a blow torch) to burn off the oil/contamination but it would probably be easier to just replace them.
Click to expand...

yeah.. I started watching a video about this, then looked at the price of new pads!

FrenchTart said:
Agreed on replacing the pads - it's so hard to get contamination cleaned out thoroughly.

You also need to very meticulously clean your rotors and surrounding area (and the calipers). Use a normal bike cleaner several times. Rinse, dry thoroughly and then use alcohol or a disc brake cleaning solution/spray. Dry again and then wipe with a pristine cloth.

Then replace your pads, not before.
Click to expand...

I normally use Muc-Off drivetrain cleaner around the rear area and normal muc-off cleaner for the rest of the bike. Is this suitable to have near the brakes? I have IPA spray that I use for other things, so can clean the discs with that.

Should I be looking at metal pads again, or resin for road use?
 
GeX said:
yeah.. I started watching a video about this, then looked at the price of new pads!
Click to expand...

Cheap pads: https://www.uberbikecomponents.com

GeX said:
I normally use Muc-Off drivetrain cleaner around the rear area and normal muc-off cleaner for the rest of the bike. Is this suitable to have near the brakes? I have IPA spray that I use for other things, so can clean the discs with that.

Should I be looking at metal pads again, or resin for road use?
Click to expand...

Get the race matrix from the above. Sintered kind of suck to be honest. Worse for noise, worse for braking performance. For normal road use I'd actually go organic 24/7 if I could find a decent cheap source.

Normally I would try to avoid getting any cleaning products near the rotors or calipers. The exception being a disc-specific one (which is really just alcohol for the most part).
 
FrenchTart said:
Cheap pads: https://www.uberbikecomponents.com



Get the race matrix from the above. Sintered kind of suck to be honest. Worse for noise, worse for braking performance. For normal road use I'd actually go organic 24/7 if I could find a decent cheap source.

Normally I would try to avoid getting any cleaning products near the rotors or calipers. The exception being a disc-specific one (which is really just alcohol for the most part).
Click to expand...

awesome, I'll take a look at those now. Assuming they're fine in the wet (given how much it rains in Manchester and I commute in any weather!).
 
Replace pads.

I got successful with boiling my discs, and then finely sanding them.

Mines were to the point of pretty much not breaking though.
 
You must log in or register to reply here.
Back
Top Bottom