SCORE Journal


SCORE Journal - The Official Publication of SCORE Off-Road Racing

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A BRAKE IN THE ACTION The Latest Off-Road Brake Technology Brings Reliability And Better Stopping Power   By Dan Sanchez In an arena where horsepower, traction, and driving skills are constantly increasing, off-road brakes aren’t often the first thing racers are eager to show off on their racing vehicles. Nevertheless, brake technology for off-road racing and for enthusiast vehicles has undergone significant changes that have improved stopping power when it’s needed most.  To find out what advancements have been made, we spoke with several brake manufacturers about the advancements in this category. Mike Hamrick, Events and Promotions Manager at Wilwood, Phil Stubbs, President of Alcon, and Edwin Mangune, National Motorsports Manager at Hawk Performance, gave us some insight into the specific needs off-road racers have, what these companies have learned over the years in competition, and selecting the best components for a variety of racing or enthusiast applications.  In speaking to the experts, we learned that in an off-road racing environment, there are many factors that can cause brake failure, including heat, dirt, and pressure. The un-sprung weight of larger tires, however, is one of the main reasons brake components have been increasing in technology and especially their overall size. “When tire size and un-sprung weight is increased, there is an extra burden placed on the brakes,” says Hawk’s Edwin Mangune. “As a first-level upgrade, we will change the brake pads with higher friction materials. If that doesn’t provide enough stopping power, a larger rotor diameter will extend the distance from the brake caliper to the hub of the rotor, increasing leverage to raise break torque.”  Improvements in brake calipers are also key to stopping a heavy tire and wheel combination, like the 40-inch diameter tires on SCORE Trophy Trucks. “The challenge is not only un-sprung weight but more so, the rotating weight,” says Alcon’s Phil Stubbs. “To maximize available brake torque, we strive to make calipers as stiff as possible, along with optimizing piston sizes to maximize clamp force.”  No matter what size vehicle, be it a SCORE Trophy Truck, Class 1 Buggy, or a UTV, in a racing or extreme high-performance situation, brake systems need to be stronger and larger in diameter to stop larger rotating masses. “We design brake systems for off-road applications to have the biggest components we can fit inside the wheel,” says Wilwood’s Mike Hamrick. “The largest diameter rotors get the most amount of torque and a large caliper will have the stopping square area needed for that vehicle’s weight and the ability to hold a brake pad that had enough volume to last the duration. It’s a balancing act, and we are trying to utilize as much area inside the wheel to achieve this.”  STARTING WITH HIGHER FRICTION PADS Although it would be great if everyone could afford a completely new set of rotors and calipers for our everyday vehicles, and race vehicles, cost is always a major concern. Complete front and rear brake sets can cost thousands of dollars, so the experts recommend starting with a better set of brake pads.  The caveat to this, however, is that it’s important to keep racing pads for racing, and performance street/off-road pads on the highway and not for racing. “Race pads are for racing and street pads are for the street,” says Hamrick. “It’s hard to get a brake pad that gives you the best of both worlds. In some segments like pre-runners, you can get away with the most aggressive street material because the vehicle will be driven on and off-road. But even with our experienced teams pre-running for an event, we’ll suggest changing from the most aggressive street material to a higher coefficient of pad that will give them the performance they want at higher temperatures they will experience while off-road.”  Aside from higher friction, true race pads are also capable of handling higher levels of heat from racing. According to Stubbs, race pads typically are metallic pads that can handle extreme temperatures. “The downside of metallic pads for the street is that they normally generate a level of noise that is not acceptable for the street. Semi-metallic brake pads are a good compromise for race and street use but will not have the high friction levels or handle extreme temperatures like race pads.”  Mangune at Hawk agrees that the noise levels race pads make on the street are the biggest complaint from enthusiasts. “Dust is the second,” he says. “Race brake pads are inherently dusty and noisy and we don’t recommend them for the street. If race pads are cold, they won’t offer immediate cold-stopping power as opposed to a street pad. In a panic stop a cold race pad may be a safety issue. As an example, we offer an HP Plus compound that offers very good cold-stopping power and a higher pad temperature range than our street pads. it’s also gentle on rotors. Because the HP Plus is our entry-level race brake pad compound, it’s very dusty and noisy.”  WHAT’S IN YOUR ROTOR COUNTS Knowing that an important step in dramatically improving your braking system over higher friction pads is a larger rotor. The experts agree, however, that not all rotors are created the same. “Heat is the leading cause of brake failure in race vehicles and brake cooling must be addressed accordingly,” says Mangune. “Premium rotors must be used or they will become warped. The driver will feel a pulse on the brake pedal and loose feel, modulation, and confidence in the entire brake system.”  The materials that aftermarket rotors are made from can make a difference in stopping power more so than just an increase in diameter. “We suggest using our highest grade of rotor material which is cast iron Spec 37. They also feature directional vanes for heavier vehicles over 3500 lbs.,” says Hamrick. “In some lighter vehicle classes like buggies and UTVs, we can work with our plate steel rotors that help tremendously with packaging inside the constraints of the wheel.”  Other racing materials that rotors are often made from are composites which have also begun to show up in off-road racing applications, but experts such as Stubbs warn about using the latest lightweight materials. “Durability is the highest priority when it comes to materials,” he says. “Lightweight materials like carbon composites are not really suitable. We use a proprietary grade of cast iron for rotors which provides good friction stability across the temperature range.”   CALIPER CREATIONS The same goes for aftermarket calipers, where the brake experts recommend that calipers must also be made from stronger materials to work properly. “The calipers contribute to the vehicle’s total un-sprung weight so reducing the caliper weight helps. In off-road applications, however, as wheels and tires get heavier, caliper weight is less significant, so strength and durability have become the higher priority,” says Stubbs.  Hamrick also argues to beware that bigger calipers are not always better. “That has always been the trend of off-road,” he says. “Six-pistons stops better than four but in most cases, that’s not true. The important factors are clamping force and how large of a brake pad volume the caliper will need to hold. A SCORE Trophy Truck (heavy vehicle) that goes very fast needs adequate clamping force to stop such a large amount of weight and hold a brake pad that will last 500-1000 miles during a race. But a UTV, being used on the same race course is much lighter and not as fast. So a smaller caliper to fit the smaller wheel and a pad with less volume can be used.  The larger/longer the brake pad that is going to be used gives us a reason to use a caliper closer to the six-piston design with staggered bores to keep the pad tapper to a minimum, so that would be what we lean toward for a SCORE Trophy Truck. For the UTV market, the pad is smaller and the vehicle is lighter, we can lean more towards a four-piston caliper, and is used quite a bit in that segment.”  RACER NEEDS AND APPLICATIONS In SCORE off-road racing, there are a multitude of custom-manufactured vehicles and modified original equipment vehicles, so brake components vary from aftermarket to factory components. Brake manufacturers have specialists available to discuss the needs of racers and their vehicles. Wilwood’s Mike Hamrick says you can call brake manufacturers directly and they are eager to help. “At Wilwood, we have specialists in short course, rock racing, and off-road. We also have specialists dedicated to our new UTV market. Because our roots run deep in racing, we have a broad scope that helps us gather data and give the best recommendations possible.”  Wilwood launched its UTV program after five years of research and extensive testing. They’ve worked with numerous racers to gather information that has proved invaluable to many teams. “We have an ongoing relationship with Jeff Proctor and the Honda Factory UTV team,” says Hamrick. “We’ve also worked with PJ Jones and his Can-Am race team and in the past year have been working with Robby Gordon and the SPEED UTVs and a viable upgrade brake system for those cars. We would not have been able to develop new Wilwood products for the UTV market without the input from all these race teams, and will continue team and driver relationships to aid in offering more applications in the future.”  Alcon is not only a brake supplier to teams like Terrible Herbst Motorsports, Brenthel Industries, Gomez Brothers Racing, and Jason Scherer, but they also recently have their brake systems used on the current SCI Motorsports Polaris racing team Gen 2 vehicles. “We’re always working with race teams as well as individual racers,” he says. “ Getting in touch with our experienced technical sales engineers is the best place to start. Based on vehicle data and performance targets, Alcon can make recommendations for the entire system including pedals, master cylinders, and more to suit specific needs and budgets.”  Just like Willwood and Alcon, Hawk has been producing brake products for decades, and many race teams use their racing-specific brake pads and their heavy-duty vehicle brake pads on chase vehicles and pre-runners.  No matter what type of braking improvements you’re looking to achieve, researching the right components for your specific vehicle is key. With the knowledge these experts have offered, your road to better-stopping power is clear and can come with the reliability of proven performance tested by SCORE racers.  Sources Hawk Performance Wilwood Disc Brakes Alcon USA

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