Overview
ISO 4249-1:1985 is an international standard published by the International Organization for Standardization (ISO) that specifies the designation and dimensions for motorcycle tyres using an inch code-designated series. This standard applies to tyres designed for highway service with a maximum speed of 150 km/h and fitted to rims with nominal diameters ranging from 14 to 21 inches. It represents the second edition, which cancels and replaces the first edition from 1978, and aligns tyre specifications with updated designations and dimensional criteria.
This part of ISO 4249 focuses exclusively on motorcycle tyres, setting standardized nomenclature and dimensional requirements to ensure interchangeability, safety, and quality in tyre production and usage.
Key Topics
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Tyre Designation:
The tyre designation in ISO 4249-1 is based on nominal section width and nominal rim diameter, both expressed in inches. This designation is typically displayed on the tyre sidewall and includes:
- Nominal Section Width (e.g., 2.00, 3.50 inches)
- Nominal Rim Diameter Code (ranging from 14 to 21)
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Dimensional Specifications:
The standard provides precise measurements for design new tyre dimensions and in-service dimensions, encompassing:
- Design new tyre overall diameter (calculated as rim diameter plus twice the tyre section height)
- Maximum overall width and diameter in service, factoring in manufacturing tolerances and tread growth
- Section height values corresponding to nominal section widths
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Scope and Applicability:
- For motorcycle tyres used in highway conditions
- For tyres mounted on rims with nominal diameters 14 to 21 inches
- Intended for maximum speeds up to 150 km/h
- Excludes tyres designed for off-road or higher speed applications
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Measurement Methods:
Tyres must be measured mounted on their corresponding rims, inflated to recommended pressures, and conditioned to ensure accurate dimensional assessment.
Applications
The ISO 4249-1 standard is critical for multiple stakeholders in the motorcycle industry, providing:
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Manufacturers and Suppliers:
Ensures tyres are consistently produced with correct dimensions and clear, standardized designation for easy identification and compatibility with rims.
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Vehicle Designers and Engineers:
Facilitates the design of motorcycle wheels and suspension systems by providing trusted dimensional standards.
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Quality and Safety Inspectors:
Offers clear criteria for assessing tyre conformity, ensuring road safety compliance for tyres designed for stated service speeds.
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Maintenance and Repair Services:
Enables correct tyre selection and replacement according to standardized sizes, improving safety and performance.
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Regulatory Bodies:
Supports the development of regulations and certifications related to motorcycle tyre manufacturing and use on highways.
Related Standards
- ISO 4223-1: Definitions of terms in the tyre industry, providing foundational terminology applied in ISO 4249-1.
- ISO 4249-2: Motorcycle tyres and rims - Part 2: Tyre load ratings, focusing on load and speed capacities.
- ISO 4249-3: Motorcycle tyres and rims - Part 3: Rims, detailing rim dimensions and specifications compatible with tyre standards.
Understanding ISO 4249-1 in conjunction with these related standards helps ensure a coherent approach to motorcycle tyre and rim design, classification, and safety across global markets.
Keywords:
Motorcycle tyres standard, ISO 4249-1, inch code-designated tyre series, motorcycle tyre dimensions, motorcycle tyre designation, tyre rim compatibility, motorcycle tyre safety, highway motorcycle tyres, tyre sidewall marking, ISO tyre standards.