To ensure you get quiet, consistent and powerful stopping from your disc brakes, it's important to keep them clean. However, there's an awful lot of different opinions on the best way to clean you disc brakes, so we reached out to a number of industry experts for their thoughts.
[Updated 22nd June 2019]
The first thing that lets most of us know that all is not right with our disc brakes is usually a lot of howling noises, stains on the rotors plus a reduction in braking power. This is usually down to oil and other contaminants on the rotor (and the pads too) that can reduce friction and therefore performance.
The obvious solution to this is to clean them, but there's a lot of uncertainty as to what is best to use to do this - any product that leaves a residue can often end up making the problem worse. We got in touch with Shimano, Fibrax, SRAM, Juice Lubes and Hope Technology to see what they recommend for cleaning your rotors and brakes and if there's anything that can be done to save a contaminated pad.
What should I use to clean my disc rotors?
When it comes to cleaning disc rotors, the general consensus is to use a specialist product that doesn't leave any residue, such as isopropyl alcohol. Hope told us "We recommend either methylated spirits or isopropyl alcohol as these both leave no residue on the rotors. Keep away from white spirit as this will leave an oily film.
"If using brake cleaners make sure you use bicycle specific ones as car brake cleaners sometimes include oil to stop cast iron discs from rusting."
James Alberts, SRAM's brakes Product Manager, has this to say: "Disc brakes work best when there is a consistent braking surface created by material transfer from the pad to the rotors. We have found that cleaning with isopropyl alcohol does a good job of maintaining this relationship while removing grime."
"We recommend a mild soap and water to clean disc brakes. This is to help avoid contamination of the pads and rotor. Brake cleaners and other sprays are unnecessary. Do not use compressed sprays to clean brakes as these can cause seal swell. We try and protect sealing surfaces as best we can with our design, but spraying a lubricant in the end of your lever will certainly contaminate your seals making your lever feel sluggish, so stick to soap, water, and isopropyl alcohol."
Rob Cook of Juice Lubes explains why their Brake Juice cleaner is specifically designed for the job: "Our brake cleaner is a bike specific cleaner, that is formulated to be low in toxicity - this is what makes it kind of seals and pads which are a lot more delicate than say those of a car where seals are much larger and in therefore tougher/more resistant to more aggressive and toxic cleaners. This also helps brake juice to prolong pad life by not causing any deterioration to the pads. Our brake cleaner won't corrode or cause oxidization to metal either so your callipers remain looking tip top and shiny!"
What causes pad and brake contamination and how can I avoid it?
When it comes to avoiding contamination in the first place, the cleaning process is important, as Ben Hillsdon at Shimano points out: "Our advice is that disc rotors should be cleaned AFTER you clean your bike to help avoid contamination. Many people will use a hose to wash dirt and grease off their bikes but the spray can find its way onto your rotors. That's why its best to leave cleaning the rotors until last. It's important also not to use the brakes during cleaning because grease from the rotors can make its way onto the pads."
James from SRAM agrees: "The most common contaminants we see are from chain lube overspray and tire sealants. Be careful to get your chain lube where you want it. Also, removing the rotor from a wheel when replacing tire sealant or installing a new tire can help prevent accidental contamination."
Ellis Blackman from Fibrax also points out a frequent culprit for contamination: "With the ever-increasing use of spray lubes, silicone polishes etc. contamination by overspray is a HUGE issue - If anything is sprayed near a bike, it'll contaminate the brakes.
"Don’t use sprays near your bike, if you have to use something, walk several meters away from the bike, spray into a rag and then wipe over [the parts]"
What should I do if my pads are contaminated?
If you've been unfortunate and your pads have become contaminated with oil, grease or anything else, there are many folk remedies for saving them, with some suggesting you should stick them in the oven or bake with a blowtorch to burn off the contaminants. None of our experts suggested this and most said the only avenue is replacement.
James from SRAM was clear on his take: "To maintain consistent performance we recommend replacing disc brake pads should they become contaminated."
That's a stance backed up by pad manufacturer Fibrax, who say a contaminated pad is fit only for the bin.
Hope holds out a little, erm, hope for those wanting to avoid a new set of pads, saying: "If the pads have surface contamination you can sometimes resurrect them by rubbing the surface on sandpaper. Just make sure you put the pads back on the same side as they may be worn at an angle."
- Avoid contamination in the first place by not using sprays near your bike and/or removing your wheels while you wash or lube the bike
- Clean your brake system with normal soap and water
- Avoid white spirit and instead use isopropyl alcohol, meths or another solvent that doesn't leave a residue to clean your rotors
- If you want to use a brake cleaning spray, buy a bike-specific one and try to avoid the seals on both lever and calliper
- Contaminated pads should generally be replaced, but you might be able to save light surface issues with a spot of sandpaper
With thanks to Fibrax, Hope Technology, Juice Lubes, Shimano and SRAM.
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