Your Guide to Find Whats Important for You and Your Brakes.

When it comes to brakes, everyone thinks that bigger is better. However, they do not take into consideration the weight and the caliper itself. What setup will be superior, one with a 14″ rotor and 6-piston caliper, or one with a 13″ rotor and 4-piston caliper? You would think 14″ rotor and a 6-piston caliper, however, that is NOT always the case. What are things to consider when purchasing a brake kit?

1. First and foremost, is the brake kit a direct bolt on, or do you need to custom-make something like a bracket. The moment you have to custom-make something, the price goes up. Most companies offer direct bolt on kits.
2. Why are you upgrading your brakes? Whether it be for show or for track, knowing the reason for upgrading your brakes is a good thing.

If you are upgrading your brakes, here are a few things to look for:

1. Type of caliper: You can have a monobloc caliper, or you can have a multi-piece caliper. Also, you can have a fixed caliper, or a floating caliper.
2. Type of material for caliper: The material matters because of the metal properties. Some materials “flex” more than others.
3. Finish: Yes, the finish makes a difference.
4. Number of pistons: This is important when looking at pad wear.
5. Piston area: This matters more than the number of pistons.
6. Rotor size: The rotor size affects the overall brake torque.
7. Rotor vane design: Straight vs curved vs solid
8. Weight: When looking at rotor weight, you have to keep in mind rotational mass. 2-piece rotors tend to be lighter than 1-piece rotors.
9. Cost and availability: You can have the baddest kit out there, but if you break something out on the track, you cannot run to the parts store and buy a replacement. You will need to special order the part, and pay more money than a standard part.
10. Brake bias: This is crucial when trying to balance braking.
11. Tires: Brakes do not stop a car, tires do.
12. Brake pads: Make sure you pick the right one for your application.
13. Brake fluid: picking one with a higher boiling point is important.
14. Brake lines: Stainless Steel braided, or rubber.

• The type of caliper and the material of the caliper both play a part in the structural design of the caliper, which translates to flex. For this, we go to Wilwood Engineering’s FAQ about caliper flex.
  • Q: Which is the more ridged Caliper, a two-piece or a monobloc?
  • A: Everything being equal, a properly designed two-piece caliper will flex less than a monobloc caliper. Stiffness is a function of the material’s modulus of elasticity. Steel bolts have an elastic modulus approximately three times that of aluminum bridges. There are some exotic aluminum alloys that were developed for F-1 racing that have almost the same elastic modulus as steel; however, they are expensive and not normally seen in after market brake kits. Steel has the added benefit of not losing its elastic modulus as things heat up. As a matter of fact, steel’s elastic modulus actually increases in stiffness as temperatures rise above 200 degrees F by approximately 30 percent, where it stabilizes at 400 degrees F. Aluminum on the other hand, loses approximately 50 percent of its stiffness by 300 degrees F.
  • Q: What is the difference between fixed and floating Calipers?
  • A: 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 a pin that is 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 a much higher efficiency are typically used on high-performance cars and for vehicles exclusively employed in racing for that purpose.
  • The finish of the caliper makes a difference when it comes to corrosion, wear, and heat transfer. Having a caliper with a finishing will protect it against rust and the elements. However, if you are racing, you are worried about heat. Nickel plated calipers also transfers heat out of the caliper body better than powder coat.
• The number of pistons and piston area are important because that tells you the force that is being applied.
• What is piston area, and how is it calculate?
  • As per Wilwood, the pistons area is the total surface area of all the pistons in one half of the caliper. The piston area can be determined using the formula: Area = pi x the piston radius squared x the number of pistons. For an example, lets use a six piston caliper and for ease of math, let’s say that all the pistons are equal in diameter at 1.5 inches: 3.14 x .5625 x 3 = 5.29 square inches.
• Why is piston area more important than number of pistons?
  • “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’re 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.”
• When racing, you want to avoid running drilled rotors. It is a common recommendation because it is said that drilled rotors crack easier than slotted rotors or solid rotors.
• When discussing how a larger diameter rotor helps braking boils down to one thing, leverage. Same applies to using a breaker bar to break loose a stubborn bolt. More force is applied to stop the car. However, a larger rotor comes with a higher cost, larger wheels, and added weight (rotational mass). So when deciding to upgrade, you have to make a list of pros and cons. Are the extra X pounds and $X worth the extra X of brake torque?
• When looking at rotational mass, a thing to consider is rotor weight. Generally, 2-piece rotors are lighter due to their design, and the use of an aluminum hat. Another advantage of a 2-piece rotor is the fact that it allows the ring to expand with heat, without affecting the hat, and since the hat is aluminum, that material dissipates heat better.
• The design of the rotor itself is crucial to its ventilation.
• Solid rotors are fine for light use, or use in the rear brakes for the street. The heat SHOULD not be high enough to cause issues. However, when you are harder on your brakes, you might want to look at a vented rotor. Not only does venting make a rotor lighter, but it helps with the cooling of the rotor.
• Straight vane rotors are very basic and provide minimal cooling compared to curve vane rotors. Curve vane rotors improve the cooling by channeling cool air from the center of wheel and act as a heat exchanger.
• When talking brake systems, something to think about is the cost of the system. It is important because not everyone has the same budget. Also, if you are at a race, and you warp your fancy 2-piece rotor, you cannot be to the local auto parts store and order a new one. You will need to order one online, and pay more money than the OE replacements at the local parts store.
• Why is brake bias important? Because brake bias slows you down. Bigger is not always better when your bias is off. When you slow down, majority of the weight gets thrown forward (weight transfer). Would it make sense to have a better kit in the rear than in the front? No, because the majority of the weight is in the front. A good thing to note is the locking of brakes. If your rear brakes lock up before your front, you have too much rear bias. If your front brakes lock up before your rears, you have too much. The key is to NOT lock up your brakes, because you do not stop. A lot of cars are equipped with ABS systems, which uses sensors on each wheel to determine if a wheel is locking up. It sends a signal to the module, which will regulate pressure to that wheel. However, ABS does not fix brake bias, it just masks it. You will need to spec out your system so that the front and rear systems work together and decrease your stopping distance.
• Why do tires play a role in stopping? Because friction. The more sticky the tires are, the more friction there is with the road. When upgrading your brakes, you must consider upgrading the tires too.
• When picking brake pads, you have to understand that a good brake pad is going to be noisy and messy. You will need to figure out if you want a race compound, or a street compound. There is no such thing as dual purpose pads. You can get a street compound with a higher temp range and use it for the track, however, it is still a street compound. And the higher the temp range, the more they will squeak when using them in the street.
• Rubber brake lines tend to flex and expand with heat. Stainless steel braided lines can handle more pressure, and would not expand with heat, just translates to better line pressure and better pedal feel.

Disclaimer: Madd Motorsports does not guarantee performance improvements or other benefits. All information is deem accurate to the best of Madd Motorsports’ ability, however, it is not guaranteed. Madd Motorsports or any company mentioned above are not responsible for any injuries, any damage whatsoever, or for incorrect installation. This is a guide meant to help, it is in no way guaranteed.