Brake Pad Info

Pagid Brake Pads - Compounds and Friction Profile

Written by Site Admin.

 

Graph shows friction vs temperature. PAGID materials are very linear as far as rubbing speed and line pressure is concerned. Since the coefficient of friction is related among other things to the brake disc material we do not show friction levels in this graph. It is only considered to show the difference among the Pagid compounds.

 

PAGID Friction Compounds

PAGID racing compounds are complex formulations with very high content of ceramic materials. All Pagid materials are asbestos free. The difference to competitor’s ‘metallic’ compounds is the superior thermal insulation and the higher heat resistance of ceramic compared to iron. Ceramic has, to the contrary of iron, very low heat conductivity. Consequently less disc (rotor) temperature goes through the pad into the caliper. We measured up to 60°C (140°F) less caliper temperatures with PAGID pads vs competitor’s pads. This is very crucial when it comes to brake fluid boiling.

PAGID friction compounds, especially the color-coded yellow endurance materials, have a very low wear rate and are extremely discs friendly. This fact is proven by numerous race wins in 24 hour races world-wide.  Brake modulation and pedal feel with PAGID pads are excellent. Consequently it is not only less likely to get (tire) flat spots but also drivability is better.

 

PAGID Steel Backing Plate Design

PAGID uses a unique and patented system to ensure the friction material does not delaminate from the steel backing plate. The friction material is attached to the backing plate in two ways, adhesive bonding and mechanical retention. The mechanical retention (patented) is accomplished by inserting ‘brass torpedoes’ (studs) -which are welded onto the steel backing plate – deep into the friction material. The ‘brass torpedoes’ do not harm the brake disc (rotor).

PAGID is the only race pad that features a retention system which not only connects the steel backing plate with the under-layer (adhesive bonding) but also with the friction material itself.

It has turned out that this system, invented in the first place only for racing, has become also the best retention system for heavy truck and bus disc brake applications.

 

PAGID Race Pad Fitting Instructions

The new brake pads must move freely in their guides. If necessary remove paint from the contact faces. Delayed release and taper wear can occur if pads do not have enough clearance.

The outer radius of the friction material must align with the brake disc’s outer radius. Especially with custom made uprights (knuckles) or custom made caliper mounting brackets very often pads do not align properly with the brake disc. It is advisable to place a note at the steering wheel to let the driver know new pads had been installed.

Never lay hot pads up side down i.e. with the friction material onto the ground unless you throw them away anyway. Asphalt, rubber, oil etc. can melt into the friction material.

 

PAGID Racing Brake Pad Bedding

If pads do not get bedded properly and / or used to hard right out of the box will likely lead to pad glazing. Pad glazing is a condition where the resins in the pad crystallize on both, the pad friction surface and the brake disc surface, resulting in poor stopping performance, brake judder and vibrations.

Also rapidly escaping volatile elements and moisture from the resin would seek an immediate escape route out of the friction compound, creating small fissures that would lead shortly to cracking and chunking.

 

Heat Cracks in Racing Brake Pads and Discs

Multiple small heat cracks (hairline cracks) are normal and accepted for this type of use. Heat cracks on brake discs must not reach to the outer or inner edge of the disc.

 

Racing Brake Pads and Humidity

When washing the car we recommend removing race brake pads or driving the car after washing and apply the brakes a few times in order to dry the brake pads. Water and even humidity of the air can slightly alter the friction behavior of racing brake pads. Some pro race teams use “storage” or “transport” pads and store the real race pads in a Zip-Lock bag until their next race.

 

Avoiding Brake Judder

During bedding and shortly after, some judder is quite normal but should disappear after 5 to 10 laps. Changing back and forth between two incompatible friction materials (e.g. racing brake pads of different brands or street pads) can cause uneven build-up of pad material on the disc surface and can consequently lead to brake judder. Judder is the result of a thickness variation in pad buildup on the disc surface. Brake judder can be from a barely noticeable vibration to a violent judder. When you install Pagid race pads on top of a layer of an incompatible pad material, bedding might take much longer or in worst case won't work at all. It can also result in sub-optimal brake performance.

Another reason for uneven pad transfer is called 'imprinting'. After coming to a complete stop with hot brakes (in the pits or after a spin), do not keep your foot on the brake pedal. The hot pads can leave a deposit behind that in turn again can cause judder and vibrations.

 

Bigger vs Smaller Pad

A larger friction surface will not improve stopping power. The amount of pressure applied, coefficient of friction and the disc diameter determine stopping force. A bigger pad does not apply more pressure, only the same pressure over a bigger area. The size of the pad matters in terms of heat capacity and wear rate. A larger pad will absorb more initial heat and has better wear characteristics.

 

Pad Fade vs Brake Fluid Fade

Pad fade

When the temperature at the interface between the pad and the disc exceeds the thermal capacity of the pad, the pad loses friction capability mainly due to out-gassing of binder (matrix) materials in the pad compound. The brake pedal remains firm and solid but the car will not stop no matter how hard you push on the pedal. The first indication is a distinctive smell, a signal to back off. Solutions: better cooling, higher mass brake discs size and vane configuration or higher heat range pad compound.

 

Fluid fade

Boiling brake fluid develops gas bubbles in the calipers. The brake pedal becomes soft and pedal travel increases (because gas is compressible). One can still stop the car by pumping the pedal but efficient modulation is gone. This is a gradual process with advanced warning. The damaged fluid must be completely replaced. Correcting the problem is improved cooling and / or may only require new or higher grade racing brake fluid. The importance of keeping fresh brake fluid in the system and regular bleeding (before every session) cannot be overstressed.

 

Watch The Temps!

It is highly recommended that brake temperatures are being monitored. Three temperature brake paints or similar products should be used. Ideally, the green paint (430°C / 806°F) should be completely oxidized (turns white), the orange paint (560°C / 1040°F) should be symmetrically beginning to oxidize and the red paint (610°C / 1130°F) should be un-touched or change only slightly.

Caliper temperatures can be monitored with temperature strips.

Checking the temperatures in the pit lane with a thermometer is a good way to oversee brake bias.

 

Disclaimer of Warranty

PAGID racing brake pads are developed for high performance events. Motorsport is dangerous. PAGID racing brake pads are sold without warranty expressed or implied. No warrant or representation is made as to this product’s ability to protect the user from injury or death. The user assumes that risk.

 

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