Are Bigger Brakes Better?
A big brake kit is an oversized caliper that is used to house an oversized brake pad. The said purpose of these kits is to increase the surface area of the brake pad hitting the brake rotor for improved braking function.
Many people upgrade their brake calipers because they think bigger brakes calipers and pads mean more braking power. Most of this thinking is perpetuated by the belief that big brakes utilize more brake pad material and therefore cause more braking friction or grip. Additionally, people notice most performance autos having them installed, and want to replicate this. It is hard for these people to believe that the big brake kits used on racing vehicles won’t increase stopping power on their own street vehicles as well.
What a big brake kit will do for a braking system is decrease the operating temperature of all related braking system components. As you may already know, heat is a brake systems’ worst enemy, and can render them ineffective after a certain point. Race cars use these big brake kits to reduce the temperature of brake calipers, pads, and fluid during heavy episodes of braking. A larger mass of brake pad allows the braking system to absorb more heat overall as there is a greater amount of material to do so. As the brake pad itself is able to take on more heat energy, the braking system stays cooler longer.
A big brake kit will not increase the stopping power of a vehicle or decrease its stopping distance due to the physics involved. A larger brake pad will only spread out the clamping force of the brake calliper over a greater area. The brake pad will always retain the same amount of friction between pad and rotor regardless of any increase in brake pad surface area. This is because the coefficient of friction law does not rely on the surface area of the materials involved; only with the type of materials involved.
Source credit: http://www.cquence.net/blog/big-brake-kits-do-they-work/