Overview
ISO/PAS 13146:2024 - Road vehicles - Brake lining friction materials - Drag mode friction test for hydraulic and pneumatic vehicle brakes - specifies a laboratory method to evaluate the friction performance of brake linings using a constant-speed drag mode. The Publicly Available Specification targets brake linings for vehicle categories M, N, O, and L and provides procedures and requirements for test benches, sample preparation, temperature measurement and result evaluation. The method simulates realistic braking conditions while focusing on the friction material rather than full vehicle assemblies.
Key topics and technical requirements
- Test scope and applicability: Drag mode friction test for hydraulic and pneumatic vehicle brakes; applicable to brake linings for vehicle categories M, N, O and L.
- Test equipment: Use of a calibrated test bench with fixtures to mount calipers and rotors (see Annex A). Effective friction radius is adjustable per requester or Annex B.
- Sample preparation and conditioning: New production linings required; surface coatings removed; rotors cleaned and conditioned by at least one complete test programme before reporting.
- Test procedures: Two control modes are specified - constant torque mode and constant pressure mode - with defined test cycles and evaluation steps. Methods A and B cover different brake assembly types and sampling approaches.
- Measurement and evaluation: Coefficients of friction (cold, operational, minimum/maximum, fading) and wear are measured and reported. Brake torque calculation and templates are provided (Annex C and D).
- Temperature measurement: Thermocouple installation is the reference - for ventilated rotors located 0.5 mm below the friction surface in the outer ring; for solid rotors positioned halfway through the friction ring thickness. Alternative methods (IR, rubbing thermocouple) may be used after validation.
- Quality limits and rotor reuse: Rotor discard guidance based on wearable thickness (manufacturer spec or 90% rule) and surface roughness/torque variation thresholds are included.
Applications
- Material development: early product screening and comparative performance testing of friction formulations.
- Quality control: production lot testing, process control and consistency checks for brake linings.
- Supplier/OEM evaluation: selecting and validating friction materials for hydraulic and pneumatic brake systems without full dynamometer or vehicle testing.
- Research and R&D: studying friction behavior, wear trends and temperature effects under drag-mode conditions.
Who should use this standard
- Brake friction material manufacturers and R&D teams
- Automotive OEMs and brake system engineers
- Independent test laboratories and certification bodies
- Quality assurance teams in braking component supply chains
Related standards
- ISO 611 (Road vehicles - Braking vocabulary) is referenced for terminology. For implementation details and national adoption, consult your national ISO member body.
Keywords: ISO/PAS 13146:2024, brake lining friction materials, drag mode friction test, hydraulic and pneumatic brakes, brake testing, coefficients of friction, brake rotor temperature measurement.