Most brakes have a safety clip to prevent the retention pin from
falling out even if it comes loose. This should be carefully removed
with a scriber and set in a safe place.
Now we can remove the old pads. Some pads will come out easily
by hand. Our pads were so cooked and full of brake dust that they
required needle-nose pliers to remove them.
On the left you can see one of the worn-out pads we’re replacing.
On the right is one of the new ones. Notice the difference in
Next, we’re going to remove the retention pin to free the pads.
Our Avid X0 Trail brakes use a 3-millimeter Allen. Simply unthread
it to remove it and then set it aside with the safety clip.
Brake-pad sets come in three pieces. There are the two pads and
the H-spring that goes in the middle of them. The H-spring helps
the pads retract when the brake is released.
Brake pads are made of two parts—the pad material and the backing plate. Pads should be replaced when the pad material thickness
wears to less than 1 millimeter, or preferably sooner. Letting pads wear more than this puts you at risk of damaging the rotor or caliper,
not to mention puts you at higher risk for brake failure. You can check this measurement using a caliper like so.