Whether you have mechanical or hydraulic disc brakes, centering your brakes takes some patience when learning. Once you are familiar with it, it will be much faster and easier. Brakes will almost always require adjustment when you first assemble the bike to be perfectly tuned. This is a critical safety step after assembling your eBike.

Please refer to the video at the bottom of the page for a quick adjustment.

If attempting yourself and you still need assistance after reviewing the videos below. Please provide a video of the noise, and pictures showing the alignment of your brake rotors and pads. This will help us understand the situation so we can better assist you. 

Possible causes of noise:

  • Disc brakes often make noise during normal operation. This can happen in certain situations like long descents, cold temps, etc. It is important to understand that noise in these circumstances is considered normal operation, cannot be reduced, and does not require attention.
  • Did you touch your brake rotors with your fingers or hand during assembly?
  • Oil or other contaminate on brake rotors or brake pads. Even oil from your finger could contaminate it.
  • Poor alignment or centering of brake calipers.
  • Bent, warped, or damaged rotor.
  • Brake rotors and pads have not been bedded or broken in.
  • Brake pads or brake rotors became hot from heavy braking and glazed over.
  • Loose brake rotor
  • Loose brake caliper
  • Loose brake pads

Brake Pad Material:

This article gives a very good overview of the pros and cons of different brake pad materials: https://www.merlincycles.com/blog/buyers-guide-to-disc-brake-pads/
In summary: 
Metallic brake pads last longer, withstand heat better, but can be noisy. They also take longer to bed in properly.
Organic brake pads are typically quieter have great initial bite, but do not withstand heat as well, and do not last as long in general.

You can purchase organic brake pads here: organic brake pads.
This support article has information and a link to a video on changing them: 
Replacing your brake pads.

This is a process that a bike mechanic will be able to perform best, but if you want to learn to maintain your bike yourself throughout the lifetime of your ownership, there are some very helpful tutorial videos available for adjusting disc brakes and removing the screeching or squealing noises that can often come with having disc brakes.

Here is some very helpful 3rd party information: 

Article with pictures: How to stop squeaking disc brakes

1st Video: As the title suggests "A Quick Adjustment"

2nd Video: Brake Bed-In Procedure for New Brakes. 

3rd VideoDiscusses noises, cleaning your brake rotors and pads, sanding your brake rotor or even filing your brake pads if they become hot during heavy braking and are glazed over.