Improving Braking Performance With Tailored Pad Selection

Ivan Korda has been considering better brakes for a while now. His NB Miata recently received a Racetech RT4100W seat to keep his broad frame stable and secure during hard cornering and braking. With one problem solved, another sprouted in its place. One of his complaints before installation of the seat was an inability to sit snugly during hard braking, but after installing the RT4100W, he found himself braking later than usual. “Whereas the old seat made my feet slide around in the footwell, the new seat allowed me to heel-toe perfectly every time. This helped me roll more speed into corners, brake later, and put together more consistent laps.” That added confidence and stability brought on one new issue, though it’s a good problem to have.

Driving on stock pads, stock rotors, and Hankook RS3 tires, Korda’s first outings to the track were accompanied by expected fade and a soft brake pedal towards the end of his sessions. Though the weight of the Miata never made driving on these basic brakes totally unsafe, Korda felt uneasy. He was leaving too much on the table with the uncertain levels of response and stopping power. He wanted more.

Over time, the stock brakes would fade, which forces the nose the remain weighted deeper into the corner than desired. (Photo: Jane Absalom)

Without spending a king’s ransom on getting the biggest brakes on the market, we wanted to have the power and consistency needed to push braking zones and facilitate the right amount of rotation on entry. Additionally, they would have to last. This Miata is just one of Korda’s many project cars, and he needed something that wouldn’t require regular maintenance.

We then turned to Hawk Performance, who were happy to guide us through the brake selection process and answer our nitpicking questions. Our conversation led us to learn a great deal about what effects certain brake components have on a vehicle’s performance. As we learned, there’s much more to consider than outright stopping power.

Korda’s first goal was to ensure better braking performance, which meant outright power and longevity. To meet those aims, all his lightweight Miata needed was good rotors, pads, and stainless-steel lines. Picking out the specific pads that would suit Korda’s driving style required a bit more thought, though.

A Pad for a Specific Purpose

With a few pointers, Hawk Motorsports Manager Edwin Mangune helped us determine the ideal set. He told us, “It’s our tires and modifications that affect pad choice the most. Prior to picking the pad, you should ask:

  1. What tires are used?
  2. How much does the vehicle weigh?
  3. What other performance modifications is the car fitted with?
  4. How much power does the vehicle make?”

Since a vehicle’s grip is primarily due to the tires it wears, tires are usually the limiting factor when it comes to choosing the right pads. “On stock or all-weather rubber, one doesn’t always need the most aggressive pads available,” began Mangune. “Even with a heavy car, our HPS 5.0 or Performance Ceramic pads should do the trick. In fact, we’ve won autocross street class championships on a near-stock Camaro wearing the HPS pads,” Mangune declared.

However, with stickier tires come greater braking forces, so a pad that can take the abuse is a must when grip is increased. With a C7 Corvette on 200-treadwear tires, many drivers opt for Hawk’s DTC-70 pads. These are quite aggressive and work well in the high temperatures brought on by a heavy, grippy car.

Whenever a track has any sort of threshold braking zone, a more aggressive pad is preferable. “Even on flowing tracks without many hard braking zones, as long as there is one threshold braking section, the driver should go with the most aggressive pads which suit the application,” Mangune advised us.

A Set to Suit Stability

With a better understanding of the thermal constraints of aggressive brake pads, we started to ponder which pads would benefit Korda, his mild Miata, and the shorter tracks he runs. Seeing that his old street tires weren’t providing outrageous grip and his braking forces weren’t as great, we decided pads with less brake torque would work better.

These would not require much time to get to operating temperature, and with slightly softer initial bite, we could expect better modulation and feel. Our hope was this arrangement would provide him with good rear stability and immediate bite. The latter trait would help his autocrossing, where limited time on-track and mild braking zones require pads that “comes on when it’s cold.” In other words, he needed pads that get up to operating temperature without much heat or effort.

The DTC-60 brake pads adorning the front axle.

These criteria helped narrow down our choices to two. With several sets of Hawk’ DTC-60 and DTC-30 pads, we could start narrowing down the right combination to suit Korda’s style. In addition to getting the pads right for the vehicle, their attack and front/rear balance would have to complement Korda’s driving style.

Where Braking Blends Into Cornering

Those of us without every bell and whistle need to get a little creative. Without a proportioning valve to set Korda’s ideal brake bias, we had to figure out which pads would provide him with the amount of torque that would help the car brake and rotate in a way he could live with. “Basically, we have to adjust brake bias mechanically via pad selection,” Mangune describes.

Going off of what we knew of the turn-in preferences of the quicker Spec Miata drivers, we considered using the DTC-60 at both axles. With this medium-torque pad braking the unweighted rear, this could help pivot the car towards the apex at the end of the braking zone. Seeing as Korda was struggling to get the right amount of deceleration and direction change there, this sounded like a solution to his problems.

The milder DTC-30 pads would help ensure stability as Korda reached threshold braking.

However, that added-torque comes at a price. The inherent nervousness at the rear of a short-wheelbased Miata meant the DTC-60 might encourage a little too much rotation. As Korda was relatively new to the car (and road racing as a whole), he opted to fit the rear with the milder DTC-30: a pad that wouldn’t have him gritting his teeth when the time came to brake.

With all these thoughts in mind, Korda installed the pads and OE rotors before setting out on a few quick laps on a quiet, unpopulated country road to bed them in properly. With a series of stops from 60 mph with 50-percent pedal pressure, he laid the foundation for track day success. He let them cool for 10 minutes, then repeated the process with twice the brake pressure before letting them cool again.

As Mangune instructed us earlier, “Bedding the brakes in properly is incredibly important. Basically, you want to transfer the outer layer of the pad onto the rotor so two similar friction rings can interact. This improves the frictional coefficient considerably.”

Putting Theory to the Test

Korda then set off to Memphis International Raceway for one of the hottest track days in August. As the waves rose off the blacktop and the cabin of his car slowly transformed into a sweat lodge, keeping focused on the task at hand was a challenge.

It’s funny how exhaustion, adverse weather, and the general stress of race preparation all dissipate once out on the track. Relieved by the staggering braking performance, he quickly forgot all about the 105-degree F ambient temperature. Korda noted, “These pads bite so quickly compared to the OE-style pad I had. The initial bite is awesome, and they inspire a lot of confidence to brake much later.”

The added stability these pads offer only compounded his growing confidence. Even when combining a few degrees of steering lock and heavy braking, the car would remain stable and never snap. That’s the sort of reassurance one needs when searching for braking points as sweat streams into their eyes.

The newfound braking force easily threw all the weight to the front, and Korda had to adjust his touch to avoid lockup. (Photo: Jane Absalom)

The temperatures made the course greasy, and with a set of three-year-old Hankook RS3s, grip was in short supply. He dealt with the occasional lockup in two ways. First, he softened his initial brake application; the previous brakes had accustomed him to flooring the middle pedal and getting little in return.

After he softened his touch, he adjusted the master cylinder rod to lower the bite point, which made it easier to add braking force more gradually. It also dropped the general position of his right foot during braking, which facilitated heel-toe. A few minor tweaks and Korda was entirely at ease.

Addressing the Finer Points of Brake Release

His comfort grew as the day went on. Even after regularly braking later and harder, he was relieved to experience no fade at all. “The brakes felt the same from the second lap until the end of the day,” he noted. Not only did that stamina help him move forward throughout the day, but the linear deployment of braking power allowed him to control the attitude of the car with more accuracy. As we’ve covered before, getting the car pointed nicely into the corner comes down to how well one can release the brake pedal.

With the OE brake pads, Korda had to carry the brakes too hard and too deep into the corner. A little too weak, these pads didn’t provide enough force to slow the car before the apex. Unable to begin releasing the middle pedal as he turned in, he had to contend with the wrong sort of weight transfer at the wrong stage.

With the Hawk pads in place, there was no such problem. Able to get the majority of the braking done before the turn-in point, he could focus on rolling the right speed into the apex. Getting off the brakes at the ideal moment was helped by one facet of the Hawk pads: their quick release. “If a driver likes to trail brake, you want a pad that releases quickly,” says Mangune. This is because finessing the car in an agitated state requires some precision. Even if the driver gets the right amount of rotation, but brakes release a hair too late because of “sticky pads,” much of the gains are lost.

By the third session of the day, he began focusing on one of the trickiest parts of braking: rolling more entry speed. “With the Hawk pads, I could trail brake consistently. This was because the brakes were predictable and easier to modulate. On the OE pads, I felt like I was constantly braking too hard at the apex just to avoid the understeer. Sometimes I’d get more braking force than I really wanted.”

With most of the braking done in a shorter distance, Korda could focus on rolling speed into the corner. (Photo: Jane Absalom)

By feeling the weight transfer more clearly under his foot, he could consistently adjust the attitude of the car towards the apex. In addition to another five miles per hour of entry speed, knowing he was on the right trajectory allowed him to get back to the throttle earlier. All in all, the increased rolling speed, shorter braking distances, and earlier throttle application consistently cut an entire second off his lap times.

Final Impressions

The nine-turn 1.8-mile MIR road course is not a highly technical track, but there are four significant threshold braking zones. With approximately a half-mile of the course made up of the drag strip and shutdown area, it highlights how important it is for a momentum car like a Miata to get through the corners faster. Ivan previously ran 1:23 laps — consistently chopping off a second is impressive — especially since pads and rotors were the only modifications he made.

“Considering the humidity pushing the heat index to 115-degrees — easily the hottest track day I’ve been to — and the worn tires making it extra greasy, I think there is a lot more left on the table for these brakes,” he assures. “I think it is not out of the question for me to be running 1:21 laps easily with no additional changes. With new tires, I could break into the teens!”

(Photo: Jane Absalom)

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About the author

Tommy Parry

Tommy Parry has been racing and writing about racing cars for the past seven years. As an automotive enthusiast from a young age, he worked jobs revolving around cars throughout high school, and tried his hand on the race track on his 20th birthday. After winning his first outdoor kart race, Tommy began working as an apprentice mechanic to amateur racers in the Bay Area to sharpen his mechanical understanding. He has worked as a track day instructor and automotive writer since 2012, and continues to race karts, formula cars, sedans, and rally cars in the San Francisco region.
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