I saw this post on a forum and thought it wasn't right, it's about why the force of frction on rotors is independent of the surface area of the calipers in contact with the rotors. I thought this was wrong because friction is a non conservative force, but am seeking further validation the post: Not really. Friction between the pad and the rotor is what stops you. And friction force is only dependent on the normal force and the coefficient of friction. The normal force is the force that is perpendicular to the direction of travel, which, in this case, is the force the pads apply on the rotor. So, since friction only depends on that force and the coefficient of friction (which depends on the material of the pad and rotor), the surface area of the contact patch has no effect on the braking performance. So, you may ask, why don't we use the smallest pads possible? Well, the more force we try and apply to a small area, the more likely that small area has of failing under the stress. So if we get more of a contact patch, that force is distributed more throughout the pad and rotor. But, braking performance and contact patch has no relation.