Overview
ISO 18885-2:2018 specifies the valve environment requirements for TPMS (Tire Pressure Monitoring System) snap-in valves used in passenger vehicles. This standard outlines essential characteristics of snap-in valve geometry, rim valve hole design, mounting processes, and key valve limits. By defining these parameters, ISO 18885-2 facilitates consistent and safe application of TPMS snap-in valves across different countries, ensuring compatibility with various rim designs and helping maintain vehicle safety and performance.
Key Topics
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Rim Hole Geometry:
The standard mandates that valve holes on tire rims have rounded or chamfered edges on the tire side and burr-free surfaces on the weather side. It also requires the flat area surrounding the valve hole to have no radial striations. These features help prevent damage to the valve during installation and use.
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Valve Protrusion Limits:
TPMS snap-in valves must not protrude beyond the rim plan on the weather side, ensuring proper fit and avoiding interference with wheel or brake components. The valve protrusion should align with common valve types (e.g., CQ09 or CQ10) for uniformity.
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Valve Limits and Stress Considerations:
The document recommends limiting valve axis deflection to 25° to reduce stress on rubber components and extend service life. For vehicles operating above 210 km/h, the use of clamp-in valves is advised due to higher stress and safety needs.
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Mounting Process and Insertion Guidelines:
Valve insertion requires lubrication as per supplier guidelines to minimize insertion force and prevent damage. The valve hole must be inspected for sharp edges, burrs, corrosion, or damage before installation. Proper seating is confirmed when the valve’s indicator ring is fully visible on the weather side, ensuring a secure fit.
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Maintenance Recommendations:
The standard notes that during tire renewal, rubberized snap-in valves should be replaced to guarantee integrity and safety. Additionally, TPMS valves must always be used with the correct sensor attached.
Applications
ISO 18885-2:2018 is vital for manufacturers and suppliers of TPMS valves, tire rim producers, automotive OEMs, and service centers specializing in wheel and tire maintenance. Key applications include:
- Vehicle Safety Systems: Ensuring reliable TPMS valve installation reduces risks of air leakage and sensor malfunction.
- Global TPMS Implementation: Harmonizing valve and rim specifications supports international vehicle markets and compliance with diverse regulatory environments.
- Wheel Assembly and Maintenance: Standardized valve and rim interfaces enable efficient, damage-free valve installation and sensor functioning during tire servicing.
- High-Speed Vehicle Usage: Provides guidance on selecting appropriate valve types for vehicles operating at elevated speeds, enhancing overall durability and safety.
Related Standards
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ISO 18885-1: TPMS Snap-in Valves – Part 1: Identification
Focuses on the identification and marking of TPMS snap-in valves to ensure traceability and compatibility.
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ISO 3877-2: Tyres, Valves, and Tubes – Part 2: Tyre Valves
Offers equivalent terminology for tire valve components, supporting clear communication across industries.
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ISO 4000-2: Passenger Car Tyres and Rims – Part 2: Rims
Covers rim dimensions and design requirements complementing valve specifications.
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ISO 9413: Tyre Valves – Dimensions and Designation
Defines standard dimensions and designations critical to valve compatibility.
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ISO 20562: Tyre Valves – ISO Core Chambers
Details specifications for valve core chambers essential for valve performance and maintenance.
Summary
ISO 18885-2:2018 establishes crucial guidelines for the valve environment of TPMS snap-in valves, supporting safe, reliable, and globally consistent installation on passenger vehicle rims. Adhering to this standard enhances TPMS accuracy, prevents valve damage, and contributes to vehicle safety by ensuring proper valve geometry, mounting, and limits. This standard is fundamental for stakeholders involved in TPMS technology, tire and rim manufacturing, and automotive safety systems worldwide.