Raybestos' 2009 police-specific brake system
Raybestos' 2009 police-specific brake system includes new rotors, high-temperature calipers... Raybestos' 2009 police-specific brake system
Enhanced Vane Configuration
Enhanced Vane Configuration, specifically designed for increased air flow throughout the rotor... Enhanced Vane Configuration
FEATURED IN VEHICLE OPS
A potato. Yes, the little spud that grows in the ground and ends up mashed, baked, boiled or au gratin on your dinner plate. Now before you think we ve changed this column to Cooking Tips, realize that if you split the average potato in half and hold each side in your hands, that s about all the surface area between the brake pads and rotors on each corner of your patrol vehicle. What you do with it and, more importantly, the products chosen to effectively manage braking can make all the difference between successfully seeing a pursuit or other Code 3 response to its resolution and ending up on the back of a tow.
The Heat Is On
Before you begin to look at products that will enhance the brakes on your patrol vehicle, you must understand how brakes work. In its simplest form, a brake system relies on the principles of energy transfer to slow you down. You might remember from your days in high school physics class (you were awake, weren't you?) that any object in motion has energy that is expressed as kinetic.Think about holding a brick in your hand. As it sits in your hand, it has the potential to accelerate by being thrown or dropped. This is known as potential energy. Once you let go of the brick, the potential energy begins to be converted to kinetic energy. However, unlike a brick, which can be instantly stopped by striking the ground, a vehicle must be slowed to a full stop. Remember: In a vehicle, we want to vary the amount of kinetic energy (speed) to correspond with driving conditions.
Vehicles rely on the principles of friction and heat transfer to gradually decrease kinetic energy levels. This is why your vehicle s brakes get hot. The more kinetic energy you have to transfer relative to the time required to do it, the quicker they become hot. In most situations, this process is unnoticed because the capabilities of the brake system can handle the required transfer of heat within the required time frame. However, during extreme driving conditions (e.g., pursuit, Code 3), extreme and repeated braking situations can cause brake temperatures to exceed 1,000 F, causing the brake system to fall behind in this kinetic energy to heat conversion. The result: brake fade.
More Bite & Less Heat
Most patrol vehicles in the U.S. rely on a brake system centered on the use of a disc brake (rotor) and friction-generating pucks (pads) that are positioned in a cradle (caliper). The caliper places a pad on either side of the rotor. When you drive, the pads stay in contact with the rotor, but the friction level is very low. Apply the brakes, however, and the pads are compressed hydraulically against the surface of the rotor, creating friction. This friction converts the forward motion of your patrol vehicle to heat, thereby slowing you down. This happens thousands of times a year to the patrol car you drive.
The development of brake pads and rotors that will survive such extreme, repeated behaviors required significant engineering. What should matter to you are the options that will help your vehicle s brake system work more efficiently and last longer. This comes in the form of better pads, rotors and calipers.
One Company s Answer
Although Raybestos has been pro ducing law enforcement spec brake pads for years, the company recently focused on braking performance from all angles. The company's 2009 police-specific brake system includes new rotors, high-temperature calipers and D3EA Police and Public Service Vehicle (PPSV)-certified pursuit-rated brake pads. D3EA PPSV certification uses independently administered, state-of-the-art, dual-end brake dynamometer testing conducted at Greening Testing Laboratories (GTL) in Detroit. As stated in Greening s D3EA PPSV test guidelines, PPSV certification captures the critical system level performance characteristics of police and other emergency service vehicles and has established performance requirements that may surpass those imposed by Original Equipment Manufacturers (OEMs).
The Pieces
Pads: The Raybestos police-specific brake pads contain high-performance materials to avoid high temperature fade, and integrate slots and chamfers on the pad that optimize cooling and suppress noise. Because stealthy arrivals are important for radio calls, Quiet Clips (rubber-coated abutment clips) and high-tech noise dampening shim materials are used for quiet braking. The pads are marked with a police-badge logo identifying the product as police use only. High-temperature silicone lubricants are used to provide optimal movement of the pad.
Rotors: Raybestos has also tackled rotor design head-on for police applications. According to the company, these police-specific Quiet On Arrival (QOA) Technology rotors are cast from damped iron and an alloy that is metallurgically formulated to disrupt vibration and suppress noise, ensuring consistent and quiet arrivals. Because heat management is essential with brakes, Enhanced Vane Configuration, specifically designed for increased air flow throughout the rotor, maintains lower temperatures with a vane configuration that channels air throughout the rotor.
When police vehicles make sudden high-speed stops, weight distribution and temperatures are inherently high on the front wheels. The more the rotor weighs, the more rotational force to be controlled. Recent fleet testing revealed a replacement ratio of 3:1 between front and rear rotors, so Raybestos optimized the weight of these new rotors to maximize life and durability.
Durability is critical because brake rotors live a miserable life and are subjected to such environmental conditions as heat, cold, ice, snow and rain. Raybestos addresses this issue with a new armor-like polymer coat that has shielding characteristics to provide greater protection against the elements.
Calipers: During police pursuits and other Code 3 responses, temperatures inside the brake caliper area can skyrocket to over 600 F. This may cause the internal components on the brake caliper to fail because the OEM rubber components simply melt. Not good. According to Raybestos, a typical OEM rubber dust boot can only withstand temperatures up to 300 F for brief periods. Raybestos has addressed this by using a high-temperature silicone dust-boot on its Police-Pursuit Loaded Caliper. The company says it can withstand double the temperature of a traditional OEM rubber boot up to 600 F for sustained periods. Pre-lubrication of critical components with high-temperature synthetic material is applied, and the caliper features new bleeder screws, mounting bolts, sleeves and copper washers, plus new phenolic pistons (where OE is phenolic) and mounting brackets (where applicable). As with the pads and rotors, the calipers are also a part of the Raybestos QOA braking technologies.
Beat the Heat
Police work demands the most from the braking system on your patrol vehicle. The demands you place on the pads, rotors and calipers are often instant. With the added dimension of equipment weight, high speeds and repeated stops, it s essential that your braking system be optimized for long-term performance and durability. Although OEM components are good, better solutions do exist. Because a few feet in stopping distance may make the difference between a crash and success, you owe it to yourself to research systems like the Raybestos Police-Specific Brake System. For more information, visit www.raybestos.com.
