"Surface coverage"? What do you mean by this? Larger brake pad contact area? If so, it is a frequent and common misunderstanding that this somehow equates to brake performance. It doesn't. All it determines is the service life of the pad due to the volume of the friction material. The formula for determining brake torque has no variable for the brake pad area. The simple version looks like this: B(t) = (F x mu) X R(c), where: B(t) = Brake Torque F = piston area (one side only) X system pressure mu = brake pad Coefficient of Friction R(c) = radial distance from the spindle centerline to the centroid of the brake pad. The K-H calipers have all of the right ingredients to be a great caliper for performance use. A decently designed rigid, cast iron body; fixed mounting - pistons on both sides of the rotor. Whether they deliver on that I've no idea, but there are plenty of other options available that do deliver. FWIW normal piston retraction by the seals is about .015". If your rotor is wobbling enough to make contact with the pads when the brakes aren't applied you've got problems. Sliding calipers biggest Achilles Heel is the sliding mechanism. Once that ceases to work as designed the inside pad wears much faster that the outer pad and the caliper isn't truly clamping the rotor - it's just pushing one side only. Which works the wheel bearings too. Then look at the actual shape of sliding calipers, they're basically a C clamp with no reinforcement around each end of the pads. Compare that to the K-H design where that reinforcement is present. If you pressurize one of each type of caliper to the same pressure and then measure the before and after body dimensions at the pad centroid you'll find that the sliding caliper has opened up 2X-10X more than the K-H design. That difference is fluid that your foot has to move. So the fixed caliper not only flexes less, but that lower flex translates into less total brake pedal movement. Translation: a less mushy pedal and better brake modulation. Sliding calipers are easier to make, that makes them less expensive and when you have to make 500,000 of an item a savings of even a few pennies on each makes a huge impact on the bottom line.
http://forum.ih8mud.com/threads/comments-on-brakes.256361/
