Disc brakes make a grinding sound I am completely new to cycling and purchased a road bike equipped with Tektro Lyra mechanical disc brakes. I have ridden an estimated 20 miles total so far and was unaware that there was a bedding in process for the brake system. My question is, how loud are the brakes supposed to be while in low to moderate use? My brakes have an slightly annoying grinding noise which sounds like metal on metal - no squealing, and they seem to shudder slightly when i pull hard on brake. I've tried reading articles and other questions to see if i can fix the issue however i am still a bit confused. If they were not bedded in properly is there something i can do instead of purchasing new pads and rotor? Any suggestions on if this is normal during the break in period or if i should do something else to remedy the situation?

Although I'm unfamiliar with Tektro Lyra's, I have been bedding in a new Shimano SLX disc brake on my commuter so have a little recent experience on this.

Given you are only 20 miles in I'd give it a little more time as this 'grinding' noise may just be the very top layer of the new pad wearing in. If it's still 'grinding' after 100 or so miles I'd take it back to the bike shop and ask them to check it over. Brake shudder may indicate the pads or calipers are every so slightly mis-aligned. There are loads of tutorials online about how to align them: <

My SLX has taken about 120-130 miles (or 2-3 weeks' daily use) to bed in properly.

Hope that helps!