The disc brakes on our woom mountain bike make loud squealing noises / there’s an oily film on the brake calipers. What can I do?

Nothing is more important to us than the safety of your child, which is why we carry out regular quality and safety controls before any bikes are shipped. During one of our regular quality and safety controls, we found some isolated incidents of residue from lubricant used within the assembly process of the Promax disc brakes, which come on our mountain bike models (woom OFF, woom OFF AIR, woom UP). In certain circumstances, there is a small possibility that traces found on brake calipers could end up contaminating the brake pads.

How could the residue have got here?

Our supplier Promax uses a lubricant during the assembly process for the brakes. Once the brakes are assembled, they are cleaned thoroughly by an ultrasonic cleaner, which removes all traces of the lubricant. If too much lubricant gets used or if the cleaning process is too short, there is a chance that traces could be left on the brake calipers, which could find their way onto the brake pads and contaminate them.

How do I know if there is any lubricant residue on my child’s mountain bike brakes?

It’s completely normal for disc brakes to have a very small amount of this residue on them – however, if there is too much lubricant residue left on the external side of the brake pads and it makes its way onto the internal face of the brake pad, it could cause a small part of the pad to become contaminated and result in a loud squeal under braking. Please listen out while riding in case the brakes begin to make a loud noise. If this squeal does not go away after a few hard brakes, there is a chance that the pads are contaminated by some of the lubricant residue. Another indicator that the brakes have been contaminated can be seen on the disc brake rotor – these should normally be shiny, clean, metal silver, but they could show a thin, black film on them if they are contaminated. Please check this too.

What should I do if the brakes appear to be contaminated?

If the brakes make this loud noise while braking or show a light, black film on the rotor, please take your mountain bike to a woom dealer or other qualified bicycle mechanic if you do not have a woom dealer nearby. Your brakes will be expertly cleaned and, if necessary, the brake pads will be exchanged.

If your brakes are cleaned or replaced by a non-woom dealer, please email your paid invoice to to claim a refund.

Please note:

- You will only be entitled to a refund if you bought the woom bike directly from our online shop.

- The invoice must display the frame number of your mountain bike.

We will refund the total amount for the work carried out using your original payment method.

I’m not sure if this issue is affecting the brakes on our mountain bike. What should I do?

If you're not entirely sure if there is any residue on the brakes of your mountain bike, or if you have any further questions, you can contact our customer service team at any time and we will be happy to help you.

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