Originally Posted by
ADAM31
I have a specialized tarmac 2021, a metal on metal sound popped up about a month ago. I thought that it was time to change my cassette and chain which it definitely was. I thought for sure that the noise would go away with that fix, but it still remains. It’s most noticeable when I am climbing out of the saddle on steep incline. I am starting to believe it’s coming from the disk brake pads possibly just slightly rubbing the disk as the bike is moving more side to side while climbing. The brakes look pretty aligned from what I can see but is it possible that they are worn out and moving just enough to hit the disk making the metal on metal sound. Otherwise the only thing I can think of it’s coming from the front small chainring. I trued the rear wheel a couple months back, but maybe the wheel is out of alignment a bit and causing the brake pads to rub on the disk.
If you have a repair stand, put the bike in it and focus on the brake rotors. I would agree that the sound you're hearing is probably from a slightly out of true rotor. You could put a line from a marker on the rotor and see if the pads rub off the mark where it's rubbing on the pads.
An out of true rim won't affect disc brakes; the rotor is at the hub. IF the disc is not in plane with the caliper, check to make sure the wheel is secured properly in the frame.