Ataher
Member
- Location
- Tripoli - Libya
Been doing a lot of reading, in spite of my previous understanding of what it is, it turned out to be simply an un-uniform friction coefficient across the rotor surface that is subjected to contact with brake pads, this is causing the friction force (stopping force) to vary around the rotor accordingly, even though the applied force (grabbing force of caliper with pads on the rotor) is uniform, and hence the shaking. A very simple way of putting it would be the following equation from school days:
Friction force (stopping force) = friction coefficient of rotor surface to pad surface x grabbing force (caliper grabbing force)
Hence, the shaking is simply the change in stopping force due to change in friction coefficient around the rotor's surface area.
So it is not a geometrical deformation by any means, and rather a permanent and an uneven material property change (or rather damage) due to exposure to temperatures above the design / working temperature of the rotor material for extended period of time, which is overheating as we know it. The change in material property causes the permanent change in its friction coefficient.
When a rotor is re-machined, the damaged layer is removed, and a new surface of fresh material with a consistent friction coefficient is in action, that is why re-machining works if done properly, provided that the cause of overheating is eliminated.
Sent from my iPad
Friction force (stopping force) = friction coefficient of rotor surface to pad surface x grabbing force (caliper grabbing force)
Hence, the shaking is simply the change in stopping force due to change in friction coefficient around the rotor's surface area.
So it is not a geometrical deformation by any means, and rather a permanent and an uneven material property change (or rather damage) due to exposure to temperatures above the design / working temperature of the rotor material for extended period of time, which is overheating as we know it. The change in material property causes the permanent change in its friction coefficient.
When a rotor is re-machined, the damaged layer is removed, and a new surface of fresh material with a consistent friction coefficient is in action, that is why re-machining works if done properly, provided that the cause of overheating is eliminated.
Sent from my iPad
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