One of the biggest attractions to drag racing is the raw, unadulterated feeling of acceleration that a run provides, but you can’t forget that at the end of that exhilarating ride, you also have to bring things to a halt. Racecars are getting ever faster, and so adequate, reliable brakes are a must. To help our KBX-powered 1995 Cobra Mustang come to a safe stop, we upgraded the brakes with a full set of binders from TBM Brakes.
Technology has allowed us to build a vehicle capable of running into the 7-second zone in the 1/4-mile with relative ease if you have enough cash. That’s truly an awesome thing, however, you need to make sure there’s enough stopping power for that vehicle, as well. The OEM brakes that come on most vehicles are only effective until a certain speed, after that you’re running the risk of brake failure. Going to an aftermarket brake setup will ensure your vehicle comes to a stop, plus it will shave some weight off at each corner.
Braking Needs For Drag Racing
A good set of brakes for drag racing need to be fairly dynamic in their abilities, but also not be too heavy. The brakes have to be able to hold a car on the starting line with plenty of clamping power, be accurate at the top end if you need to tap them to play the stripe, and bring the car to a stop after a fast pass. How heavy the car is and the power it’s making also must be factored into selecting the correct set of brakes.
Many may think that an OEM-style brake kit might work for their car, but they’re missing an opportunity to gain performance on the track and in the car’s braking ability. Jason Smith from TBM assists customers with getting the right brakes for their rides each and every day and explains this further.
“It’s all about finding that happy medium between the stopping power needed and weight of the brake package. Your OEM brake system is going to work just fine with the correct brake pad, however, they are going to be extremely heavy. All of that extra weight is something that you want to remove in drag racing. We design these kits around the idea of maximizing the stopping power while removing as much weight as possible,” he explains.
With engine and power adder technology allowing virtually any car to be turned into a single-digit monster at the track, focusing on the car’s stopping power becomes important. OEM brakes are going to struggle in these conditions because they weren’t designed for this kind of speed and horsepower. The brake pad compounds aren’t made to deal with the extra heat generated, and the braking systems don’t have the power required to clamp down hard enough to stage the car properly.
“The OEM brake pads have temperature ceilings to operate in street driving conditions. They won’t have the ability to help stage the car with enough clamping force when there’s a lot of horsepower being applied,” Smith says. “The pads also won’t have the temperature ceiling to deal with a situation where the brakes need to stop the car if a parachute doesn’t deploy and there are temperatures of 1,200 degrees reached. These are all things that we put into the design of our pads and brake systems that aren’t built into an OEM-style braking system.”
It’s all about finding that happy medium between stopping power needed and weight of the brake package.
When we got our 1995 Cobra Mustang it was already set up for drag racing duty, but in the search for lower elapsed times at the track, the brakes became a target for improvement. The TBM kit was the perfect fit for our goals since it would shave weight off the car while still providing plenty of stopping power for a car that weighs over 3,000 pounds in race trim.
“The kit used on the Mustang is designed for a car that can weigh up to 3,500 pounds and can go 200 mph. When the kit is installed, the front brakes only weigh 14 pounds while the rear weighs just 21 pounds. Is that package made for all forms of motorsports? No, but it works well for drag racing and allows for all of that weight saved to be moved to other areas of the chassis. The stopping power provided by this kit is just as important, you don’t have to sacrifice clamping force while saving weight,” Smith says.
What Goes Into A TBM Brake Kit
When you get a brake kit from TBM you’re getting a well-thought-out product that has everything you need to get it installed included. The big components like rotors, pads, and calipers are all in the box along with the hardware required to complete the installation for your application. Every part of a TBM brake kit was designed with function in mind and to provide end-users with the best brakes possible.
TBM didn’t design their rotors to just look pretty, though — they have a purpose in the design to help fight many of the issues that can impact the performance of the brakes. Typically, a lightweight steel brake will heat up quicker on the inside and outside diameter and that can lead to warpage issues. TBM wanted to get in front of this with their rotors while keeping weight down and performance up.
“The convoluted design of the rotor helps lead to flatness as the rotor starts to get heat-soaked during use. It’s also taking a lot of weight off the rotor, so it’s designed to stay flat while being abused and keeping heat in check. The rotors are made of mild steel that goes through a thermal process and they are Blanchard ground to maintain flatness. The end-user is getting a piece that’s been heat cycled and flattened already,” Smith explains.
Contact with the rotor is executed by the brake pads. The pads have to provide a high enough coefficient of friction to stage a car with no heat in them. These pads also have to be able to bring the car to a stop while dealing with the heat generated at the end of a run.
“The pads have to be able to hold a car while it stages and be made of a compound that will work when heated to 1,500 degrees. It’s complicated to come up with a compound that can do both things, but our Number 85 compound that’s included in our drag kits does this. Materials-wise, it’s a semi-metallic based compound,” Smith says.
Guys will take the car out, make a bunch of passes, and then let it sit for a while. The best thing to do if this happens is to go through the break-in process again by scuffing the rotor face with sandpaper and lay a new transfer layer of material down.
TBM wanted to ensure its calipers were up to the job of providing enough clamping force to bring the fastest cars to a halt in a hurry. This requires a rigid unit, so they make their calipers out of a 2618 forged aluminum that actually gains strength when it sees heat. The goal is to have a caliper that doesn’t want to give up any clamping power when it is engaged.
“The rigidity of the calipers we design is the nucleus of everything in our brake kits. What we strive to do is build a strong caliper so everything else can fall into place around it. That strong caliper allows for proper piston retraction — when you have proper piston retraction you are alleviating any brake drag. When you remove that drag you don’t need as big of a rotor so you can save weight,” Smith says.
The fixed caliper design is yet another advantage over OEM disc brakes, which are typically a floating design that is prone to drag and not nearly as rigid.
Installation And Maintenance Tips
The installation of the TBM brake system is really simple since everything you need for hardware is included, along with complete instructions. The kits will fit most front suspension types and rearends. Where the TBM kit requires a bit more care is in making sure the caliper is in the correct location.
“What’s critical is getting the caliper parallel to the rotor, so we include a lot of shims to help with this. You’ve got all of these tolerances that start stacking up with the assembled parts and that will affect the caliper’s location. If that caliper is not parallel with the rotor when the brakes are put under load it’s going to want to twist and bind to make itself straight,” Smith explains.
For those who may not have tried to make a caliper parallel, Smith explains a few different ways to get it done.
“The first way is to measure or mic everything to see exactly where it is in relation to the rotor. You can also get the whole system plumbed and set up as close as possible and then back out the caliper screws a little bit. You can have someone apply pressure to the brake pedal and that will cause the caliper to go where it wants to be under load. If you see the caliper twist or move that’s where it wants to be as far as being parallel. You can add shims so it stays in that location after it moves.”
Getting the brakes ready for use is fairly simple according to Smith. You need to scuff the rotor face with 60- or 80-grit sandpaper to remove any plating — this will also put a good crosshatch pattern on the face of the rotor for the pads to lay a transfer layer of material on. Since the pads have already been heat-treated and exposed to a thermal cycle they don’t require much to break in. Making one pass down the track and getting on the brakes hard will help seat everything and then you just need to let them cool down on the return road.
Brake inspection needs to be done before a car hits the track each time. This is something that TBM recommends before and after each race to catch issues early. There are some additional items that Smith recommends when using TBM brakes.
“The biggest thing we like to see people do is scuff the rotor face before a race weekend if the car has sat for a long period of time. Guys will take the car out, make a bunch of passes, and then let it sit for a while. The best thing to do if this happens is to go through the break-in process again by scuffing the rotor face with sandpaper and lay a new transfer layer of material down.”
The TBM brake kit on our 1995 Cobra Mustang helped to cut some weight while still ensuring the car will stop quickly after a pass in the 4.30-second range. We plan on putting these brakes to the test throughout the 2019 season and beyond at events across the country.