Brake System 101: Rotors and Pads
By Richard Fong
There’s no point in being able to go if you can’t stop. While an engine provides motility to a car, the braking system is what brings your vehicle to a stop. Typical brake systems are hydraulic and include a pedal, master cylinder, hydraulic lines, calipers, rotors and pads. The braking system is not only an important performance element, it’s also an imperative for safety and the safe operation of a vehicle.
As is often the case, many standard vehicle components are designed as a compromise of quality versus price. With the exception of premium vehicles that include performance brake components from the factory, most vehicles are equipped with little more than adequate braking systems. Take that vehicle to the track or even on a spirited drive, and you’ll quickly learn its shortcomings. Imagine accelerating down a stretch and then braking just before engaging a turn or a series of switchbacks. The first time works fine, shaving speed and hitting the apex of the turn with ease. One or even two laps later, that same braking area seems to get shorter, as you soon find yourself stomping on the brakes to adjust your speed in order to engage that same turn. The pedal feels mushy, the brakes don’t have any bite and before you know it, you’re way past the apex and are either off line or off track. This is the ugly face of an insufficient brake system, known as fade.
Fade isn’t your friend. Brake fade is the enemy of safe and reliable braking. Brake fade occurs when the friction efficiency and/or heat capacity of the brake pads or rotors is exceeded and the ability of the brake system to slow or stop the vehicle becomes compromised. Whether it be on a twisty mountain pass or on a racetrack, finding the limits of braking leaves much to be desired. Fortunately, a quick look toward the aftermarket could be the answer to your problems, as it probably offers a solution for your application.
Bring Back the Friction
One of the first and most straight-forward upgrades you can invest in are brake pads. Brake pads, like rotors and fluid, are wear items that can be upgraded. Brake pads are composed of a backing plate and a friction compound that creates friction when placed in contact with the brake rotors, enabling a vehicle to stop.Brake pads offered by STILLEN, Ferodo, Hawk Performance, Mintex, Pagid and T-Rex are offered in a variety of friction compounds ranging from organic and ceramic to semi-metallic. Each pad type and compound is optimized depending on your vehicle’s intended purpose.
(Common OEM Material)
Pros: Less aggressive rotor wear, decent initial bite, manageable brake dust generation
Cons: Mediocre braking performance, tends to wear quickly, prone to brake fade
(Common OEM Material, Aftermarket Upgrade)
Pros: Moderate rotor wear, good wear characteristics, less prone to brake fade, moderate dust production, ideal for rotors lacking slots or cross drilling, the middle ground between organic and semi-metallic pads
Cons: Higher cost, limited compound options, less aggressive friction traits, not ideal for the track
(Common Aftermarket Material, Aftermarket Upgrade)
Pros: Broad selection of available compounds, improved resistance to fade, improved heat rejection when used on slotted or cross-drilled rotors, permits tailoring of braking performance traits depending on driving conditions by changing compounds
Cons: Potentially aggressive rotor wear, excessive dust, noise (brake squeal)
Pick Your Pad
Organic pads offer good initial bite (initiation of friction and slowing of the vehicle) and modulation for daily driven vehicles, but generally suffer rapid wear and fade when subjected to aggressive driving. Ceramic pads cost more but take the best traits of organic pads and can add longevity as well as reduced brake dust production. However, these pads suffer accelerated wear under heavy loads and are not ideal for track or heavy-duty braking situations. Semi-metallic pads tend to resist fade better and offer superior heat capacity and dissipation compared to organic or ceramic pads. They are offered in a variety of compositions enabling the end user to choose the braking characteristics desired of their vehicle. When choosing a semi-metallic pad, aggressive initial bite could be desirable in the case of a vehicle driven hard for short intervals. The counterpoint is that this pad could eventually suffer from fade with prolonged aggressive driving. By comparison, a semi-metallic pad formulated for endurance offers increased heat capacity for longer driving intervals but will likely lack initial bite when cold and suffer reduced braking performance until brought up to optimal operating temperatures. This is not ideal for short driving intervals or street driving since the ideal temperatures are much higher and might not be reached under these conditions.
Release the Heat
Another common brake system improvement involves upgrading the surface that the brake pads apply friction to, the brake rotors. Brake rotors are not only a friction surface, they’re also heat sinks. This means that they must draw away and dissipate the heat produced by the friction with the pads efficiently to ensure consistent braking performance and to stave off brake fade. Factory brake rotors are typically composed of iron due to cost, longevity and heat capacity for the everyday driver. However, to save on cost, typical factory rotors do not benefit from the design elements and heat dissipation characteristics of aftermarket brake rotors.
Aftermarket brake rotors, like those offered by STILLEN, AP Racing and DBA, can feature a variety of benefits thanks to engineering innovations such as improved vane design (in the case of vented rotors) as well as cross drilling, slotting and other surface treatments. In the search for improved methods of heat dissipation, some manufacturers of vented rotors have implemented proprietary vane designs to facilitate improved airflow for better cooling of the rotors. As an added measure of cooling, some have turned to cross-drilling the rotor surface. However, it is not unheard of for cracks to develop between the holes of a cross-drilled rotor after repeated heating and cooling cycles over time. Another brake rotor type is the slotted rotor. The slots cut into the rotor surface help to optimize the friction surface area while helping to release the gasses that build up between the friction material of the pad and the rotor surface. However, this rotor type also causes accelerated wear on the pads, shortening the typical service life of the pads.
Step Up and Stop Better
With a better grasp of the basics of brake upgrades and the first steps toward better braking for both performance and safety, contact us to order your upgrade today! Do you have more questions about what would be right for your application? Reach out to us at 866-250-5542, at firstname.lastname@example.org or by live chat on our website stillen.com to help you select the product that best suits your needs.
In our next installment of STILLEN University, we’re going to explore brake system upgrades in greater detail. Check back with us soon!