Problem with caliper brakes of Pure Fix Original Series I bought a new bicycle about a month ago (this bicycle) and I have been having problems with the brakes. When I brake, it sounds as if metal is rubbing against metal. I went back to the shop a couple of times, they adjusted the brakes a little bit and told me that everything is fine. After a couple of days the problem reoccured. Here is a photo of the brake pad:



It looks like tiny pieces of metal are stuck in the brake pad. And here is a photo of the rim:



The rim looks like it chips a little bit or maybe is scratched. I see two options here: (1) I caught some debris from the road (2) The brake pads or/and rims are defective. I ride in relatively clean but dusty environment. Could this be caused by debris on the road? Could this be caused by defective brake pads? How could I solve this problem?

Any help is much appreciated!
Tiny metal fragments from the rims embedded in the brake pads is fairly common, although the amount you have in yours looks excessive to me.

The rims may have not been machined very well and had poor surface finish which lead to the high level of contamination of the pads. As the rims wear in this should decrease. You don't want to leave all those bits of metal in the pads, you can pick them out with the corner of a razor blade or replace the blocks.

You could try smoothing the rim braking surface with something like Scotchbrite to remove any loose particles. I would not use anything much more abrasive than that.

Don't worry about circumferential scratches on the rims, they will be smoothed out by wear in time.