ISO 5273:2025

Overview - ISO 5273:2025 for passenger car tyres

ISO 5273:2025 defines a standardized method to prepare new passenger car tyres in an artificially worn state by removing tread rubber (for example by cutter, buffing or grinding) specifically for subsequent wet grip testing. The standard describes conditioning, marking, controlled tread removal, measurement, and acceptance criteria so that tyres used in wet-surface performance tests have reproducible, documented tread geometry and surface texture.

Key topics and technical requirements

• Scope: Preparation of artificially worn tyres for wet grip tests; applies to new passenger car tyres.
• Equipment: tyre tread removal machine, tread depth gauge (ASTM F421 recommended), test rims (max radial/lateral runout 0.5 mm), image recording, and surface roughness measurement (ISO 21920-2).
• Conditioning & environment: vulcanized tyres conditioned >24 h; test ambient 5 °C to 40 °C; tyre surface temperature during buffing must not exceed 110 °C.
• Inflation: operating inflation pressure during measurement and removal 180–220 kPa.
• Marking & measurement: procedures to calculate reference tread width (C) and central part (CP), mark transversal and circumferential measurement points, and record initial groove depths.
• Target groove depths: central part target 2.0 mm; shoulder control area ≤ 2.0 mm (see Table 1).
  • Individual CP depths: 2 mm ± 0.4 mm
  • CP groove average: 2 mm ± 0.2 mm
  • Recommended standard deviation for all tread depths: **