ISO 5751-1:2010

Overview

ISO 5751-1:2010 - "Motorcycle tyres and rims (metric series) - Part 1: Design guides" provides design guidance, designation rules and the calculation methods for dimensions of metric-series motorcycle tyres. It applies to tyres with reduced height/width ratios (100 and lower) intended for cylindrical bead-seat or 5° tapered bead-seat rims, and can be extended to other tyre/rim concepts when appropriate rim/section ratios and coefficients are defined.

Key topics and technical requirements

• Tyre designation and marking

  • Sidewall markings must show size and construction and service description (load index and speed symbol).
  • Construction codes: B (bias‑belted), - (diagonal), R (radial). High‑speed categories use VB/ZB/VR/ZR and special marking conventions.
  • Mandatory markings for tubeless tyres (“TUBELESS”) and rotation direction arrows where applicable.

• Calculation of design dimensions

  • Procedures to compute the theoretical rim width, design section width, section height, and overall tyre diameter.
  • Rim/section ratio K values given for aspect ratios (examples: K = 0.6 for 100/90/80; 0.7 for 70/65/60; 0.9 for 45–30).
  • Rules for choosing the measuring rim width and rounding conventions.

• Maximum and minimum service dimensions

  • Maximum overall width and diameter in service are calculated using coefficients (a, b) that depend on tread configuration (Types A–D) and tyre construction.
  • Minimum section width requirements and tolerance rules (minimum difference and measurement procedure).

• Load‑carrying capacity and speed

  • Tyre load‑carrying capacity (TLCC) linked to load index; applicable up to 210 km/h, with defined percentage reductions for higher speed categories (V, W, VB/VR, ZR/ZB).
  • Guidance on centrifugal radius and factors to account for service growth and deformation.

• Measurement procedure

  • Mount on measuring rim, inflate to recommended pressure, condition 24 hours at room temperature, then measure.

Applications

• Use this standard when designing or specifying:
  • Motorcycle tyre geometry and tyre-to-rim compatibility
  • Vehicle clearance and wheel arch design (vehicle manufacturers)
  • Tyre labelling, marking and product compliance (tyre manufacturers)
  • Regulatory documentation, test houses and OEM procurement

Who uses it

• Tyre designers and manufacturers, rim designers, motorcycle OEMs, homologation authorities, testing laboratories and component engineers.

Related standards

• ISO 5751 (Parts 2 and 3) - dimensions/load capacities and approved rim contours
• ISO 4249 (code‑designated series)
• ISO 4223-1 (tyre industry terminology)
• ISO 6054 (rim codes for small diameters)

Keywords: ISO 5751-1:2010, motorcycle tyres, metric series, tyre designation, tyre dimensions, load‑carrying capacity, speed symbols, rim/section ratio.