WHY DON’T YOU MAKE A 6 PISTON CALIPER?
Contrary to popular belief, the number of pistons has nothing to do with the performance of the caliper. The most often cited reason for companies that do make 6 piston calipers is that they have more clamping force which, for a given caliper size is patently false. Another reason given is to “equalize” the force on the back of the pad to stop taper, which is also false, (see question 2 for more clarity).
The fact is that clamping force relates to two very important factors, caliper rigidity and piston surface area. The real truth about surface area is that in a given amount of space on one side of an opposed piston caliper, 2 pistons will always have more surface area than 3 smaller ones. One further claim by advocates of 6 piston calipers is that “it enhances the proper location of force on the pad”, which is also immaterial to the results of torque output.
WHAT IS THE PURPOSE OF THE “REVOLUTION ROTOR”?
Rotor choice is based upon two important factors in calculating requirements for a given application. First, the diameter of the rotor determines the “effective radius”, which is an important dimension in calculating brake torque output. There are several choices when determining the component requirements for any application, such as piston size and quantity, line pressure, effective radius, size of wheel and tire, etc.
The math to reach a certain torque level can be achieved with a variety of combinations, but before we look at that, let’s look at the other important determination, that is heat dissipation. Heat dissipation is a factor of the number of stops and the frequency. For example, a drag car only makes one stop, whereas, for example, a formula car makes more stops, more frequently, for a longer period of time. Therefore, the rotor becomes a major factor to keep the temperature within the limitation of the brake pad maximum operating temperature. Unless you have super high requirements for heat dissipation, then large diameter, heavy vented rotors are not your best choice. SMALLER DIAMETER ROTORS ARE ALWAYS PREFERABLE AS THEY CONSTITUTE “ROTATING WEIGHT” WHICH IS THE MOST UNDESIRABLE WEIGHT ON A RACE CAR.
The “Revolution Rotors”, because of the proprietary way they are manufactured, have the capability to withstand incredible abuse without cracking, warping or failing. They will withstand far more thermal input without failure than many heavier rotors. Because of the far lighter weight, they offer a major improvement in acceleration and deceleration resulting in major lap time improvements. They are low cost, high value components, that when combined with an efficient “Zero Drag” caliper, such as ours, will improve your performance for far less expense than adding horsepower.
WHY DID YOU CHANGE YOUR NAME TO “TBM BRAKES”?
The Brake Man was originally started with the intent to provide high quality, long life components to the racing industry because of the vital importance to improving lap times at a considerably smaller expense to dumping more money in the engine. In the beginning, the development was started in a 2000 square foot garage. The grassroots motorsports people who were our original customer base, quickly grew to become a much larger audience across all forms of vehicles. As we have grown, it has become apparent that our company was far better served with a name that reflected our “core business” and reflected our commitment to the automotive performance industry.
As our “ZERO DRAG” calipers have gained market share, the name needed to capture the true quality of the product being sold. Our original Icon, “Billy Joe Brakepuck”, departed as we widened our appeal to all racing groups and organizations.
We are known for top rate quality products and the best service after sale in the industry so we hope our customers and potential customers find the name change to their liking.
WHY DO MY PADS WEAR TAPERED?
Virtually every brake company in the industry has a significant problem with tapered pad wear. Regardless of whether they stagger the piston sizes or not, the taper is significant. The actual cause is caliper flex. As caliper flex increases, the more the taper.
TBM Brakes, because of the far superior caliper rigidity reduce the flex so effectively, that it will only be seen under the most adverse conditions, and even then, far less than any of our competitors. The reason is that we have simply produced such a rigid unit that the minimal flex even at extreme line pressures results in very little spreading thereby reducing the pad taper.
The significance of the strength of the caliper results in 3-4 times pad life in our caliper as the “Zero Drag” effect, combined with the caliper rigidity effectively increases the pad life by eliminating cocking and reduced pad temperatures. THE SINGLE BIGGEST CAUSE OF A “MID CORNER PUSH” IN A RACE CAR IS BRAKE DRAG. Virtually every caliper on the market creates wheel drag to some extent and significant drag when they super heat on the race track. If you don’t believe it, try to spin your wheel immediately on entering the pits. Can you afford that horsepower loss at the rear wheels?
WHY DON’T YOU RECOMMEND SILICONE BRAKE FLUID?
Seal compatibility is critical to caliper performance. Very simply put, silicone brake fluid has a very undesirable effect on ethylene propylene rubber found in most brake systems. This tendency to swell the seals, combined with the fact that silicone is compressible when heated or in high altitudes creates unwanted changes to the pedal travel. Seal swelling can also cause brake lockup when used hard. Either of these changes in travel can be so extreme as to cause complete pedal loss or the vehicle dragging to a stop. Therefore, we highly suggest our DOT 5.1 Xtreme 6 fluid, or a comparable DOT 3 or 4 compatible fluid.
WHY SHOULD I PAY MORE FOR YOUR CALIPERS THAN OTHER BRANDS?
The true cost of a product is not what it costs to buy it. The true cost is what it costs to “use it”. In the case of a brake caliper, this is measured by the capability factor, combined with the costs of the consumables factor.
The capability factor is a measurement of the life and resultant benefits. For example, our “Zero Drag” caliper so effectively reduces drag that far more horsepower is transmitted through the driveline. To replace that horsepower by making the engine more efficient would cost approximately 10 times as much. Also, the biggest single cause of a “mid corner push” is caused by that brake drag. This affects the steering control and consequently, lap times negatively. In other words, steering control is enhanced, usable horsepower is enhanced, as is the overall driving control.
The consumables factor is the second point to consider. Due to the fact again, of the “Zero Drag”, our calipers eliminate maintenance and brake pad wear by as much as 70 percent. This means that for every 3 sets of pads you now wear out, our calipers wear out 1 set. Just consider the cost of those pads and the resultant overall cost of your system as a result. Just remember, we have not even assigned a value for the cost of your, or someone’s labor to replace them.
In conclusion, a high quality brake system will always benefit you in the long run.
WHY ARE SOME COMPANIES RECOMMENDING TWO CALIPERS PER WHEEL?
Clamping force is a function of line pressure times piston surface area on one side of the rotor. All calipers have a maximum pressure rating and every company but ours recognizes 1200 psi (pounds per square inch), as being their rating. However, TBM Brakes calipers are rated at 1500 psi. When you combine this with the loss of clamping force that most calipers see because of deflection, (clam shelling open), they can’t develop sufficient clamping force to get the job done.
If they must recommend two calipers per wheel, they are adding to the unsprung weight, covering up the ability of the rotor to effectively dissipate heat and still creating excessive drag not seen with ours.
You should also note that if they are selling you twice as many calipers that don’t do the job, then why not buy one that will? It won’t cost you any more.
WHY DO YOU RECOMMEND PLUMBING IN -3 HARD LINE VS. BRAIDED?
A master cylinder has very limited resources for volume of fluid for supplying the system. When you plumb a car in braided line, the line can “flex” under pressure, growing in size. This increases the volume of fluid in the line and decreases the amount reaching the caliper. This creates a longer than necessary stroke. As the brake line grows, it slows the response time of the caliper to react with the rotor. A vehicle traveling at 65 miles per hour is traveling at about 100 feet per second. This obviously can easily contribute to an accident you could have easily avoided.
The line size is also critical. -3 line size is the most practical for virtually every application. The reason is simple. Line size critically influences speed of delivery of volume. Even though slight, in a closed system, -2 line restricts flow much like a freeway going from 4 lanes to 2 would slow traffic. -4 line increases the flexibility of the braided portion of the line which can cause a spongy, low pedal. Remember, it is little items like this that can make a major difference in the overall “feel” and response of your pedal.
WHY DO YOU RECOMMEND SMALLER ROTORS THAN YOUR COMPETITOR’S?
The function of the rotor is twofold. First, it provides a lever to magnify torque output of the caliper. Second, it provides a “heat sink”, to remove the heat generated during braking. Since our caliper provides greater clamping force, then the need for a large diameter rotor is not necessary.
Rotating weight is the most undesirable weight in a car. One pound of rotating weight is the equivalent of 10 pounds of sprung weight to the “feel” of the car. By installing larger than necessary rotors will slow the acceleration and deceleration of the vehicle. If you want it because it looks cool, then do it. Just know that the car will not perform as well with it.
WHY DO YOU RECOMMEND RESIDUAL VALVES WITH YOUR CALIPERS?
The purpose of a residual valve is to maintain a very minimal line pressure to keep fluid in its proper location. A secondary benefit is it reduces pedal travel, which is particularly advantageous where pedal travel is limited.
In a vehicle where the master cylinder is located lower than the position of the caliper, reverse fluid flow can take place and the fluid in the caliper will flow backwards to the master. This could cause total pedal loss on the next brake application. In a situation like this, a residual valve is mandatory.
It should be noted that some “pseudo experts” will tell you it will make the calipers drag. This is not true. Most residual valves in use today are two pound valves. All calipers have rubber O’rings that will retract the pistons with approximately an 8-10 pound force.
The reason that in some calipers that it appears to “create drag”, is because the caliper is “flexing” open a larger amount than the O’ring can retract the piston, so the caliper is at fault, not the residual valve.
Due to the high degree of accuracy of our valve, (all residual valves do not share the accuracy of ours), we have developed a wide range of inlets and outlets to provide several choices for our customers. For example, we are now the biggest supplier of valves to aftermarket Trike companies. As a result, virtually any combination of -3, 1/8” pipe and 10 mm ends can be assembled per your requirements.
Remember, not all valves are sufficiently accurate. A 2 pound valve must be 2 pound, not 3 or 1. If it is 1 pound, that will not be sufficient to stop the fluid flow out of the caliper resulting in pedal loss. If it is 3 or worse, more, then the drag could cause sufficient heat to create drag that would eventually lock the wheels.
It is for this reason we always insist on a residual valve with our “Zero Drag” caliper.
CAN YOU OFFER SOME GUIDANCE ON 1 PIECE VS. 2 PIECE VS. 2 PIECE FLOATING ROTORS?
A rotor serves two primary purposes the first of which is to act as a lever to accent the caliper force. The second of which is to dissipate the resultant heat generated during braking sufficient to keep the pads within their thermal capabilities.
From a cost standpoint, the one piece rotor is the least expensive and is used where thermal requirements are low and cost is a major factor. This type of rotor is commonly used where the maximum speed, frequency of use and durability requirements are minimal. In most cases, this type of rotor fulfils the requirements of the application and at a very low cost.
The two piece rotor, when properly designed, will be more efficient, capable of a wider temperature range and less expensive to replace if the wear surface of the rotor requires replacing. These are used where the rotating unsprung weight is a more critical component in the overall functionality of the vehicle, such as in racing, or when the sprung weight of the vehicle will be increasing and no overall loss of vehicle performance is important. There is a basic law of physics principal that indicates removing one pound of rotating unsprung weight is the equivalent of over 10 pounds of sprung weight. This type of rotor will be used where vehicle modifications will be increasing the vehicle weight, top speed or frequency of use. If a two piece rotor is chosen in these situations, the capabilities of the brake system will be improved.
A two piece floating rotor is, at best, a bit of a misnomer. Thermal expansion of dissimilar metals, in many cases, will eliminate the float in many “floating designs”. As stated earlier, the need for a floating rotor certainly has extremely limited applications, especially if you have a “Zero Drag” caliper such as ours. By effectively managing the thermal energy being input into the rotor allows the choice of lighter and more basic designs focusing on effective air management through the rotors. Because of the potential negative effects on the reliability of the brake system, this style of rotor should not be considered unless absolutely necessary due to special concerns that can’t be solved with two aforementioned styles of rotors.
WHEN AND WHY SHOULD TEMPERATURE PAINTS BE USED?
Brake pads are specifically created to work well within a certain temperature range. In the various forms of racing such as shorter events where rotor temperature usually does not reach extremes, a lower operating temperature pad would be ideal. As the severity of use and length of time of the race increases, higher and higher operating temperatures put more severe demands on the pads and therefore, it is important to know the maximum operating temperature.
When applied to a surface, our temperature paint quickly dries and forms a dull and opaque film. The film liquefies when heat is applied to that surface and the rated temperature is reached. As the surface cools, the liquefied paint re-solidifies to leave a distinctly different mark, confirming that the target temperature has indeed been achieved.
It is best, on a vented rotor, to choose 3-4 paints in the expected temperature range. Pick consecutive veins and apply the paint across both the vein and onto the top of the outer rotor face. By painting both surfaces, the vein area should remain marginally cooler than the face. You may see that the paint has melted on the outer friction surface, but the vein still shows the intact paint. On a solid rotor, only the outer surface of the rotor should be painted but you would read the indicated paints the same way.
By using paints of varying temperatures, you can find the required operating range and be able to select pad compounds specifically designed for your requirements. It is important to know that temperatures are highly affected by the driver, so don’t assume that just because another driver at your track tells you his operating temperature that it will be yours as well.
We also have been asked about the temperature paints that change color to indicate temperature. They are available, but do not indicate temperature as accurately as our single temperature paints. The reason is that single temperature paints are accurate within 1% of the indicated temperature. The color change paints are nowhere near as accurate. For this reason, the single temperature paints are a preferred choice to make a proper decision on brake pad choices.
Regardless of the type of paint you use, they will prove the value of our “Zero Drag” calipers in reducing rotor temperatures. Our calipers, because of the reduced temperatures, make available a far wider range of compound choices. They also extend the life due to reduced temperatures.
WHAT ARE THE MOST IMPORTANT ASPECTS OF BRAKE PADS?
The final component in developing torque from a brake system is the brake pad. To reiterate, the brake pedal supplies leverage for pressure based upon the ratio. The master cylinder supplies volume based upon the caliper requirements. The caliper determines the master cylinder volume requirements based upon its structural integrity. The rotor supplies the effective radius based upon the thermal dissipation requirements.
Finally, if all of the above factors were properly coordinated to work effectively together, the LAST question you should ask is: What is the highest coefficient of friction pad you have? The reason is adequate clamping force has been achieved to properly stop the vehicle. Therefore you don’t require the pad to overwork. In fact, you should be looking for stability, not the highest torque.
All pads have a torque output curve from ambient to their maximum temperature capability. If you choose a pad with a flatter torque curve, the balance between the front and rear brakes will remain consistent. If not, the front will achieve their maximum torque capabilities first while the rear brakes are still cold. This means the race car will develop a “push”, meaning the front brakes are doing more than their share of the work. Later, as the brakes heat soak, the front pads will overheat first meaning that the coefficient of friction will drop. At the same time, the rear pads are just achieving the ideal temperature for optimum performance meaning the rear of the car is now overworking and making the car feel “loose”.
A good driver can always “adjust” in a racing situation to make allowances for the car. However, it is virtually impossible to get the best performance from a car that is changing its corner entry characteristics every lap.
That is why pad choice is so important. Obviously, the wear rate has to be adequate for the length of the event, and choosing a pad that is rotor friendly will prolong the life of those rotors, but the most important characteristic is to obtain repeatability in the deceleration to achieve the best, and most consistent, lap times.
Don’t ask for the brake pad to make up for your brake system design mistakes!
PLEASE EXPLAIN USING PRESSURE GAUGES TO SET UP BALANCE AND MAINTENANCE.
To achieve maximum deceleration, the key is to match the line pressure to the weight on the wheel during deceleration so that all four wheels would theoretically lockup at the same time.
Since the speed at which the brakes are applied is the key to weight transfer, and subsequently the front to rear bias, the balance bar allows “fine tuning” to the pressure at the calipers.
The brake pressure gauges are as critical as the tire pressure gauge and the tire temperature gauge to achieve maximum vehicle on track performance. Prior to any event use a “bathroom” scale or other device to simulate on track input force on the pedal. Adjust the balance bar all the way to the front and measure the front/rear percentage output. Then adjust the balance bar all the way to the rear and repeat measuring percentage output. You now know your full range of adjustment available.
On an asphalt track, take the car up to full speed emulating a race condition. (If you don’t the front to rear bias will not match race conditions and your bias will be off). Dial brake to the rear until you can feel the rear achieving lockup. Take one turn back to the front and you are now as balanced as possible using all four tires to the maximum. If you cannot achieve this goal, then you may need to resize the master cylinder choices.
If you are using TBM Brakes, you will quickly see that due to the caliper rigidity, and subsequently, no premature rear brake lockup, you will be able to dial in far more rear brake thereby reducing the load and wear on the front brakes. Most dr