When I apply the front brake
（well, actually I only brake with the front wheel）,
there's this metallic grinding sound like metal scraping metal,
so I took a look at the rim side and found that
a white stripe had formed on the left side that looks just like Cassini's Division.
It's not 100% the source of the noise,
but it's safe to say most of it comes from this.
In the left brake shoe
metal fragments aren't embedded—they're wedged in the gap.
It's impossible to completely remove this stuff all the time,
but if you make a point of at least removing
the bits that are obviously visible and audible,
it makes a real difference in how long your rim lasts.
（well, actually I only brake with the front wheel）,
there's this metallic grinding sound like metal scraping metal,
so I took a look at the rim side and found that
a white stripe had formed on the left side that looks just like Cassini's Division.
It's not 100% the source of the noise,
but it's safe to say most of it comes from this.
In the left brake shoe
metal fragments aren't embedded—they're wedged in the gap.
It's impossible to completely remove this stuff all the time,
but if you make a point of at least removing
the bits that are obviously visible and audible,
it makes a real difference in how long your rim lasts.