Original CP Racing Brake Caliper AP9440 Fit Brake Disc Rotor 330*28mm​

4 Pot calipers means that the brake calipers are holding 4 pistons. Different types of calipers (the thing that holds the pistons themselves) will hold different amounts and types of pistons. The calipers themselves are made from a variety of materials, steel and aluminum being the most popular - steel for durability, and aluminum for weight. The more pistons the better the braking power and pedal feel. The piston itself is normally made of stainless steel, which is durable. The pistons in the brake calipers are actuated by hydraulic fluid called brake fluid. (typically glycol-ether, but there are other brake fluids such as silicone based fluids out there. Brake fluid is classified by dot 1, dot 2, and so on. ) Glycol-ether absorbs the water around it which affects the boiling temperature. For example, glycol-ether 5.1 boils at 518 degrees F when dry, and only 374 degrees F when wet. Brake fluid must also stay liquid at cold temperatures or the brakes will literally freeze up. Many added safety features such as ABS require this to operate right. You have to change your brake fluid fairly often, depending on usage and type of Dot fluid you are using.

Cars use a variety of ways to increase the mechanical advantage one can apply with the brake peddle. Namely leverage and hydraulics’. Typical the brake is a ways out from the pivot point, which gives you leverage. So say it is 4 times farther away from the pivot point then the pedal cylinder. Then the pedal cylinder sends the force to the brake cylinder through the brake fluid, and the brake cylinder is larger which increase's the mechanical advantage. That cylinder then pushes the piston (which has the brake pad on it) on to the rotor, which is attached to the hub, which is attached to the wheel. However, all of this friction on the disk brake cause's a lot of heat. So most brake discs have vents in them to cool them off.

The brake disc itself is made of cast iron, which can take temperatures of around 2000 degrees Fahrenheit before is starts to melt. So to make it so that they can take more heat they make larger disc brakes, which dissipates the heat better, and it can take much more temperature before failing. This is why a race car will have much larger disc brakes then a normal car.

The brake pads themselves take quite a bit of heat as well, which can cause pad taper. Pad taper is where one side of the pad is being worn down faster then the other side, making the pad uneven. That is one of the reasons cars that have to brake more will have more pistons, as it spreads out the wear and force on the brake pad more evenly allowing better peddle feel and better distribution of force on the pad for more consistent stopping power and wear. The more pistons the better.

FAQ
Q: How long the delivery time?
A: For sample, need 4-7 working days For quantity order, need 10-12 woking days
Q: Can the big brake kit be customized?
A: Yes, all of our big brake kits can be customized to meet the needs of different customers
Q: Can you make my own logo on the big brake kit?
A:Yes, we can make your own logo if needed, feel free to let us know when you'reready and we'l discuss the details
Q: Can your packaging be customized?
A: Whether it is inner packaging or outer carton, we can design it according to yourts
Q: How do you make our business long-term and good relationship?
A: 1.We keep good quality and competitive price to ensure our customers benefit
2. We respect every customer as our friend and we sincerely do business and make friends with them, no matter where they come from