I recently purchased a brand new Scott Genius 950 at a local bike store. After bedding in the brakes, I noticed a rattling noise while riding coming from the front disc brake. I brought it back to the bike shop, they disassembled the front brake and put it back together, but the noise is still there.
I was told to bring the bike back when the head mechanic is in, but I thought it would be worth posting a video of the noise here. It seems to act up the most when I turn sharply left or right. It doesn't always rattle, and it does it when I am not braking.
Maybe it isn't the brake, but the spokes? I am not really sure.
I just got back from the shop, the head mechanic took the front brake apart and put it back together. I rode it around the parking lot for a while, and just now around the neighborhood. Seems that the noise is gone (for now!).
I asked what he did, but I don't remember all of the technical details. Definitely re-aligned everything, tightened everything, mentioned something about [retracting?] the spring, etc. I wish I remembered more of what he said so I could share it here.
I just got back from a test ride around the neighborhood. I can still get a slight rattle out of it when dropping the front end after doing a wheelie. Since the front brake has been rebuilt by the shop mechanic, I am not too worried about safety. From the feel of it, nothing is loose, and I have full stopping power. I suppose I will just have to learn about it on my own, and continue to investigate.
So, I am able to reproduce the noise (only for a fraction of a second) when dropping the front end down, hitting a curb at an angle, and turning sharply. It makes a very quick, very quiet ching noise. From this, I am now thinking that it may be from the flexibility of the fork causing the rotor to make brief contact with the pads. After learning how the disc brakes on my bike really work, I am not concerned that this will be a safety issue, and may wear in with time if my conjecture is correct.
I found some interesting information after looking at the dealer's manual for my brakes: SHIMANO Hydraulic Disc Brake 4-Piston Caliper Model: BR-MT420
On Page 8 about a third of the way down the page it reads "The 203 mm and 180 mm disc brake rotors have a larger diameter than the 160 mm disc brake rotor for cross-country bicycles, and so the flexing of these disc brake rotors is greater. As a result, they will interfere with the brake pads.".
Very interesting, as those are the exact size of the rotors on my bike. So maybe this is normal and expected?
Thank you to everyone who has responded, and if anyone has any further ideas or experience with this issue, please reply :)