Why do my disc brakes keep becoming contaminated?

[Tim1023]

Before a ride, I dribble lube onto the chain as I turn the cranks by hand. Detailer/wax spray is applied in close proximity to the rotors. When I finish with a ride, my bike is covered in dirt, grime, hydration drink, mud, sweat, plant debris, and sometimes even coyote poo. Magically, my brake rotors are always perfectly clean, untarnished by any of these nasty "contaminants." The brakes run fine.

Perhaps it's time to revisit the assumptions regarding the impact of "contaminants" on brake performance. Just sayin'...

Yup. It was like that on my old Stumpy. Never even thought about the brakes except for topping up the fluid when the levers started feeling a bit soft. Brake contamination was simply not a thing to worry about. Those were Shimano brakes too.

 

[2WheelsNot4]

In many years only ounce i had a contaminated disc.
The shop made a mistake and it was on a SRAM system.

Shimano are known for micro leaks , and also for brakes weeping past the seals in winter. Sure can happen with some brakes, but the majority is with Shimano.

You don't get this with Hope

 

[Tim1023]

Shimano are known for micro leaks , and also for brakes weeping past the seals in winter. Sure can happen with some brakes, but the majority is with Shimano.

You don't get this with Hope

So if you have Shimano, all you can do is Hope