Brake Calipers

The primary difference between a fixed or floating caliper is in the mounting design. Fixed calipers are solidly mounted to the spindle or bracket, and floating calipers float on pins that are attached to the spindle . Fixed calipers have opposing inner and outer pistons. Floating calipers have only inner pistons and rely on outer pad carrier movement to apply pressure to the outer pad. Floating calipers tend to be more forgiving to OE manufacturing tolerances hence they are used on the vast majority of production cars. On the other hand, fixed mount calipers that transfer PSI within the caliper into braking performance with higher efficiency are typically used on high-performance cars and purpose built race cars.

Larger caliper pistons will provide more clamping pressure on a given axle, and therefore increase the braking performance of that axle, providing the tires and suspension are able to transfer that brake torque to the road effectively. If the caliper pistons are too large for the application, they are likely to cause excessive pedal travel and an adverse change in front to rear balance resulting in longer stopping distances. It is also possible that clamping forces can become so strong that pre-mature lock-up will occur, making brake modulation difficult. 

Radial mount caliper and brackets offer an additional axis to make adjustments while maintaining the rigid mount. The radial design accommodates rotor diameter changes with a simple spacer rather than a whole new bracket.