Friday, October 21, 2016
Brake Pad Part No: 15J-10003K-B

Brake Pad Guide Brake Pads Chart

Brake Pads
High-Temperature Racing Pads

Pad#:   8521
Compound:   PolyMatrix J
Wilwood Brake Pad Plate #8521

Wilwood Brake Pad Plate #8521
zoom image
<Go Back>

Call (805) 388-1188

Product Number: 15J-10003K-B     Price: $322.50
Pad Dimensions
Thickness(in): Area(in²): Volume(in³): Beded:
.83 9.2 6 Y
Temperature & Friction Ratings
Peak Temperture Rating: Peak Friction Rating:
1300+ F. 0.58
Dust & Noise Ratings
Dust Production Rating: Pad Noise Rating:

Performance Characteristics
  • Medium-high friction, consistent response.
  • Flat torque curve, less aggressive than A or H compounds
  • Low wear rate
  • Medium-high friction, consistent response.

Vehicle Applications
Driving EnvironmentVehicle Sub-TypesApplication Duty
Rally Heavy Duty
Road Race Heavy Duty
Late Model Asphalt ASA, All Pro, SW Tour, etc...Heavy Duty
Stock Cars NASCAR, BGN, CTS, ARCA, etc... Heavy Duty
Late Model Dirt STARS, UMP, IMCA, etc...Heavy Duty
Northeast Modified Dirt or PavementHeavy Duty
Open Wheel Sprint, Midget, etc… Dirt or PavementHeavy Duty
Off Road Heavy Duty

Pad Illustration and Dimensions
Wilwood Brake Pad Plate #8521 Large Drawing

Wilwood Brake Pad Plate #8521 Large Drawing

Compound Characteristics
PolyMatrix J

PolyMatrix J

Compound Data Sheet

  • Race ONLY compound endurance road racing and super-speedways with iron rotors.
  • Fast intermediate ovals requiring less aggressive brake response.
  • Popular "tuning" compound to reduce bias against A, B, or H compounds when additional hydraulic adjustments are not available.

  • Gradual rise from to medium torque as temperature increases.
  • Long wear and high temperature fade resistance.
  • Tuning pad for reduced response in medium to high temperature ranges.
  • Compatible with all iron and steel alloy rotors.
Compound Temperature Range & Torque Values
Temperature range and overall friction value are the primary considerations for pad selection. The pads must be capable of maintaining the proper amount of friction for stopping power within the temperatures that will be realized on the track during the event. Then, overall wear rate must be considered. For most asphalt and road race applications, compounds in the high temperature ranges over 1000°F range are usually necessary. Dirt track, drag race, and street performance applications usually operate at temperatures between 500° and 1000°F. Keep in mind that these are general ranges, and not absolute values. Many factors and unforeseen influences can affect brake temperatures. The best indicator for pad selection will always be on track performance. If pad fade (friction loss) due to overheating occurs, then improved cooling, a heavier rotor, or a higher temperature range pad may all become necessary.