Spoon Caliper

[tinkerbell]

would anyone care to explain why the pistons are different sizes?

[cordz]

would anyone care to explain why the pistons are different sizes?

"The pistons are smaller on the leading edge and grow in size toward the trailing edge in order to balance the pressure and heat on the pad. Balancing the pressure is critical to pad wear, keeping them from tapering or cracking. Uniform pad wear and pressure also benefit pedal feel. To minimize pedal travel and provide the most consistent feedback, it’s essential that all areas of the pad make contact with the rotor at precisely the same time."

SOURCE (I suggest everyone have a good look to see how a caliper works):

http://www.caranddriver.com/features...aliper-feature

My 2 cents:

Based on this information, I take it that because the first piston is the smallest, it would require the least amount of fluid to engage the pad at a given pressure. Therefore, more fluid can be directed to the larger trailing pistons, whose bigger surface area would compensate for their lower internal piston pressure.