What is the brake caliper: the brake caliper is the assembly that houses the brake pads and pistons.
How the caliper works : the brake caliper is like a clamp that fits on wheel's brake rotor. When the brake pedal is pushed a brake pump push the hydraulic oil through hoses and activate the piston in the caliper that creates a braking friction between the pads and the rotors linked to the wheel to slow and eventually stop the car.
What material is made a caliper: a caliper can be of cast iron or aluminum. The calipers in the older vehicles are mostly cast iron while newer ones feature aluminum calipers. When it comes to the caliper pistons, the materials to make them are more varied. The pistons can be chrome plated steel, plastic or aluminum.
What is a floating caliper: the floating caliper moves with respect to the disc, along a line parallel to the axis of rotation of the disc; a piston on one side of the disc pushes the inner brake pad until it makes contact with the braking surface, then pulls the caliper body with the outer brake pad so the pressure is applied to both sides of the disc.
In a floating caliper there are one or two large diameter pistons on the inboard side of the brake rotor.
What is a fixed caliper: a fixed caliper does not move relative to the disc and is thus less tolerant of disc imperfections. It uses one or more pairs of opposing pistons to clamp from each side of the disc, and is more complex and expensive than a floating caliper.
On fixed calipers, there are small-diameter pistons on both sides of the rotor and can be 4, 6, or even 8,10,12 pistons per caliper with 2 pair of pads for racing Gt cars. Big diameter rotor, starting from 310 mm needs bigger pads and more pistons to push in the proper way the pads on the rotor.
What is a radial caliper: it is a caliper secured via bolts that run parallel to the discs
What is an axial caliper: it is a caliper held in place with bolts that are perpendicular to the discs.
Source:
https://en.wikipedia.org/wiki/Disc_brake#Calipers
https://fr.maxpeedingrods.com/buyer-guide-brake.html
https://mzwmotor.com/brake-caliper-guide/
https://www.wilwood.com/brakekits/brakekitsprodfront?itemno=140-14067
https://www.tarox.com/en/product_cat/competition-calipers/
edited by arrabbiata
