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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?

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    Tektro stuff can be a bit problematic on the cheaper end as you've found out. I'd suggest going back to the shop you bought the bike and getting them to look at it (they shouldn't charge you for this).
    – Batman
    Apr 28, 2017 at 14:28
  • Unfortunately, i purchased online through the bike manufacturer, but will take to my LBS if problems persist.
    – mgroader6
    Apr 28, 2017 at 14:50

4 Answers 4

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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: http://www.bikeradar.com/gear/article/how-to-align-your-disc-brake-calipers-32591/

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

Hope that helps!

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    To be clear, bedding is a process that should be done to completion before the bike is ridden for real. All the manufacturer guidelines would have it that doing it as you go is problematic because bringing the bike to a complete stop before the process is complete can create an uneven transfer layer.
    – Nathan Knutson
    May 1, 2017 at 0:02
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From your description there are two different areas this could fall under: problems with adjustment that are causing the rotor to hit the disc caliper or adaptor, or problems with bed-in.

They shouldn't be loud under normal braking. You should get some slightly "textured" feedback as the pad bites down on the rotor as you use the brake, but it shouldn't shudder. That you mention shudder is the clue something is wrong here.

The first thing you should do is double check very carefully that the brake(s) in question are not adjusted such that the rotor can ever get contact the caliper body or the caliper adapter (if present). It should only ever be able to touch brake pad. If it's contacting anything else, hopefully it's just a case of re-adjustment, but too much riding like that can destroy things.

If that's not the problem, i.e. everything is adjusted properly but it's giving these symptoms anyway, the first thing I would do is remove, lightly sand, and re-install the pads, then lightly sand the rotor(s) and clean thoroughly with alcohol or brake cleaner. Then do a thorough bedding procedure after reading some good long thing that explains the theory and practice of bed-in. If they still do it, replace the pads. If they still do it after that, replace the rotor too. Some of the brakes out there now have this tendency to just start making a rapid-fire shudder when you brake, as the pad goes over the cut-outs of the rotor, and I don't know that it's even something that has to do with bed-in. Maybe.

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A bit of noise is not uncommon with discs, if the wheel spins freely don't worry too much unless its annoying you. The tolerances are very fine, so the slightest disk warping cause a bit of rubbing. A bit of dirt and grit also does it....

Mechnical disks usually have one pad fixed and move just one. If the fixed pad is a little too tight it will rub. You may need to undo the fixed pad a fraction and tighten the on that turns the same amount.

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The main problem is light braking may glaze the brakes decreasing overall braking effectiveness.

The common practice is ~30 hard stops is needed to bed in the pads.

So the best thing to do is go for a ride and get up to 30+ km/h and then brake hard down to stopped. Repeat. And then see if your brakes work better.

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