Easy way to clean rotors.

[fooferdoggie]

With our tandem, it tends to get rotors that make noise because of the heat and the steep 18% grades we have to go down. We keep the speed down and long descents, and once in a while, a rotor will be squeaky. Sandpaper will fix it, and sometimes sanding the pads. But sandpaper is pretty slow on the rotors. Well, I found a really fast way. I use Bar Keepers Friend (there are others like Comet and such) and a Scotch-Brite pad. Just get a small section of pad wet enough to fold over the rotor, a bunch of abrasive, and water, and it only takes a minute at most to get the black stuff off. Sandpaper takes a lot of work then, since with water, you are done. of course after this you need to bed in the pads and doing it right makes a huge difference. thinking about it putting more abrasive on the disc and squeezing the lever a bit and running the wheel would clean the pads too I bet.

 

[Aushiker]

Is this what you are referring to?

 

[spokewrench]

The last time I bought brake pads, I had to choose resin, semi-metallic, copper, multi-metallic, or sintered. If heating results in squeaking, maybe another pad material would prevent it.

 

[fooferdoggie]

Is this what you are referring to?

yep. any of those lightly abrasive cleaners should work.

 

[fooferdoggie]

The last time I bought brake pads, I had to choose resin, semi-metallic, copper, multi-metallic, or sintered. If heating results in squeaking, maybe another pad material would prevent it.

I have air-tech rotors 203mm and I have tried all the pads right now they are ceramic. thats been the best combo. but the problem is the heat is really fast and short. so its about instant heat for maybe 10 seconds then its done. the right rotor is all that made the difference the pads dont have time to transfer the heat. without air tech rotors one 1 block downhill run was enough to start messing them up.

 

[spokewrench]

Earplugs!

 

[Chargeride]

I had the most insane squeal on my last ride, I scooped some puddle mud and poured it over the rotor and pads ..gone within minutes.

 

[stompandgo]

Barkeeper's Friend contains oxalic acid, the same stuff that is in CLR, the fluid that melts rust. Protect yourself accordingly.

 

[Chazmo]

Barkeeper's Friend contains oxalic acid, the same stuff that is in CLR, the fluid that melts rust. Protect yourself accordingly.

Oooh, thanks for that, stomp… I use the stuff and I never use gloves. Errrrr… maybe that explains a thing or two. Oh, and I used to play with mercury when I was a kid. D’oh!

 

[6zfshdb]

I used to use Comet and a damp sponge. I switched to Magic Erasers with a drop or two of water. Just fold the damp pad over the rotor and squeeze while spinning the wheel. Rinse & reuse with Less mess and easy to carry in a bag or pannier. An easy fix for noisy rotors while on the go.

 

[spokewrench]

the problem is the heat is really fast and short. so its about instant heat for maybe 10 seconds then its done

I wouldn't hold a brake for 10 seconds. Instead, I'll brake sharply, maybe 2 seconds at a time, or I'll alternate between front and back.

Come to think of it, that's how I braked on hills with rim brakes in the 1960s. I see the Bike Gremlin agrees, whether it's rim brakes or disk brakes.

Bicycle braking technique on long descends | Bike Gremlin US

How to brake safely on long bicycle descents: correct braking technique, physics explained, avoiding brake overheating, and common downhill braking myths.

bike.bikegremlin.com

When the brake is off, the rotor is pulling a film of air between itself and the pad. A given descent will generate a certain number of calories. If the brakes are off more seconds, more of those calories will be dissipated by the moving air film instead of flowing deeply into the pad and rotor. Maybe that will prevent squeaking.

 

[fooferdoggie]

I wouldn't hold a brake for 10 seconds. Instead, I'll brake sharply, maybe 2 seconds at a time, or I'll alternate between front and back.

2 seconds on a 450# tandem may bleed 2mph off on a 18% grade with both brakes. One place we have to keep the speed below 10mph as it’s a T intersection. Longer grades not so steep, it’s different. The tandem if I let it loose on that one block hill would hit 40mph on a residential road with people pulling in and out. Pretty much all the steep roads we are on are not ones you can just let go. One longer one we were on Saturday I can brake nard then let up coast and repeat. But the short ones are the worst for fast heat.

 

[fooferdoggie]

I used to use Comet and a damp sponge. I switched to Magic Erasers with a drop or two of water. Just fold the damp pad over the rotor and squeeze while spinning the wheel. Rinse & reuse with Less mess and easy to carry in a bag or pannier. An easy fix for noisy rotors while on the go.

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thats an idea. I dont need to clean on the go though. I figured comet would work too but I dont have any. I clean my ss pans with the barkeeper friend sandpaper really sucks unless its attached to my sander (G)

 

[Chazmo]

Good stuff, foofer! I imagine a tandem down a steep grade needs extra heavy-duty brakes.

 

[fooferdoggie]

Good stuff, foofer! I imagine a tandem down a steep grade needs extra heavy-duty brakes.

The bike came with 180mm rotors and 2-piston shim calipers. We were going slow, but we could not stop it on a steep trail. It did come with a rim brake, so that was too scary for it, but that was on the back for my wife so it could not be used all the time unless I could yell at her. We used it on longer descents.

 

[Rás Cnoic]

Had terrible contamination on a front set of mechanical discs a couple of years ago. Tried sandpaper on the pads, alcohol on the rotors nothing worked. Chucked both pads and rotor in the dishwasher and hey presto after a normal 3 hour cycle, clean and sparkling!

 

[spokewrench]

18 percent sounds intimidating. How do you ascend? A 450 pound bike would need 368 newtons, or 243 newton meters on a 26" wheel.

On my Radmission, my gross weight was over 300 pounds. The mechanical front brake would consistently stop me from 20 mph in 20 feet. That's 15mph per second. The limiting factor was almost going end over end. Going down an 18% grade, that would have limited my braking to 12.3 mph/s. Of that, 3.8 mph/s would have been needed to counteract gravity, letting the front brake slow me at 8.5mph/s.

On a grade like that, it appears that I could stay between 5 and 10 mph by letting it accelerate to 10. Applying the front brake at 60% would bring me down to 5 in 1 second. I'd let the brake off, and in 1.3 second, gravity would bring me up to 10. That's a cycle of 1 second of fairly hard braking followed by 1.3 second of cooling air.

I used to clean rotors, trying to get rid of squeaks. Now I just quit using the quiet brake until the squeaky one behaves. I think using a brake harder can generate brief heat to change what's on the rotor, like bedding.

 

[spokewrench]

Had terrible contamination on a front set of mechanical discs a couple of years ago. Tried sandpaper on the pads, alcohol on the rotors nothing worked. Chucked both pads and rotor in the dishwasher and hey presto after a normal 3 hour cycle, clean and sparkling!

There was a period when extended foggy humidity softened the resin pads on two bikes. They would contaminate rotors. Washing rotors with detergent in a bathroom sink cleaned them. Then I'd have to rebed. I discovered that washing with plain water would clean the rotors. Those deposits must have been water soluble.

In prolonged high humidity, I discovered that if I heated pads with a hair dryer, they wouldn't mess up rotors.

 

[Rás Cnoic]

I recently changed my front rotors from 160s to 180s because of steep descents around here, usually 15-20% occasionally 25% and up. The 180mm rotors make a massive difference. Wish I'd done this years back.

 

[PedalUma]

Then I'd have to rebed

Rebedding is supper important not only for freshly cleaned rotors but more so on a honeymoon. One guy wanted to buy brake oil. I said mineral, DOT 3, 4, 5.1? He said whichever will make the screech go away. He had tried some non-bike oil and it didn't work.