Data Sources & Industry Standards
TireSize.app calculations are built on authoritative industry standards and verified manufacturer data. Transparency in our sources ensures trust and accuracy.
Our Commitment to Accuracy
Every tire size calculation, fitment recommendation, and safety guideline on TireSize.app is backed by authoritative sources from the tire industry, automotive manufacturers, and engineering standards organizations.
We do not rely on user-generated data or unverified sources. All specifications are cross-referenced with multiple authoritative sources to ensure consistency and reliability.
Data Verification Process:
- ✓ Cross-reference with at least 3 independent sources
- ✓ Verify against OEM manufacturer documentation
- ✓ Validate with industry standards (TRA/ETRTO/SAE)
- ✓ Update quarterly as new vehicle models release
- ✓ Expert review by ASE-certified technicians
Primary Industry Standards
Tire and Rim Association (TRA)
Official Website: us-tra.org
What We Use From TRA:
- Official tire dimension tables (width, diameter, circumference)
- Load index and load capacity ratings
- Speed rating specifications
- Rim width compatibility ranges
- Tire construction standards (radial, bias-ply)
- Section width tolerances
Key Publications:
- TRA Year Book (annual tire standards)
- Passenger Car Tire Standards Manual
- Light Truck Tire Standards Manual
TRA sets the official standards for tire dimensions in the United States. Our diameter and circumference calculations for P-metric and LT tires strictly follow TRA specifications.
European Tyre and Rim Technical Organisation (ETRTO)
Official Website: etrto.org
What We Use From ETRTO:
- Metric tire sizing standards (millimeter measurements)
- European load index tables
- Rim contour specifications
- Tire pressure recommendations
- Inflation pressure/load relationship tables
- Agricultural and industrial tire standards
Key Publications:
- ETRTO Standards Manual
- Data Book (tire and rim dimensions)
- Engineering Design Information
ETRTO provides internationally recognized standards used across Europe, Asia, and increasingly in North America. Essential for metric tire sizes and international vehicle specifications.
Society of Automotive Engineers (SAE)
Official Website: sae.org
What We Use From SAE:
- Vehicle dynamics calculations
- Speedometer accuracy standards (SAE J1226)
- Tire and wheel test procedures
- Gear ratio effect calculations
- Suspension geometry principles
- Automotive measurement standards
Relevant SAE Standards:
- SAE J1226 - Speedometer Test Procedure
- SAE J1810 - Tire Labeling
- SAE J2047 - Tire Performance Testing
SAE standards inform our speedometer error calculations, gear ratio analysis, and vehicle dynamics assessments when changing tire sizes.
National Institute for Automotive Service Excellence (ASE)
Official Website: ase.com
What We Reference From ASE:
- Best practices for tire installation and service
- Safety guidelines for tire modifications
- Proper tire inspection procedures
- TPMS (Tire Pressure Monitoring System) guidance
- Wheel alignment specifications
- Tire rotation patterns and intervals
Our ASE-certified team members ensure all recommendations align with professional automotive service standards and safety best practices.
OEM Manufacturer Specifications
We maintain a comprehensive database of original equipment manufacturer (OEM) tire specifications for 40+ vehicle brands covering thousands of models.
📖 Owner's Manuals
Primary source for factory-recommended tire sizes, pressure specifications, and load ratings. We reference official OEM documentation from manufacturer websites and printed manuals.
🚪 Door Jamb Stickers
Vehicle-specific tire information placard located on driver's door jamb or glove box. Contains tire size, pressure, and load information specific to your vehicle's configuration.
🔍 Service Bulletins
Technical Service Bulletins (TSBs) from manufacturers regarding tire-related updates, recalls, or specification changes. Essential for identifying updated recommendations.
🏭 Dealership Data
Partnerships with authorized dealerships provide access to parts catalogs, service manuals, and trim-specific tire information not always publicly available.
📊 Industry Databases
Professional automotive databases (Mitchell1, AllData) used by repair shops worldwide. Provides comprehensive vehicle specifications and tire fitment data.
🔬 Real-World Testing
Physical verification of tire fitment when possible. Our team tests clearances, measures actual dimensions, and documents real-world compatibility issues.
Covered Vehicle Brands (40+):
Tire Manufacturer Technical Resources
Michelin Technical Guides
Official tire data books, load/pressure tables, and fitment guides from the world's largest tire manufacturer. Particularly valuable for performance and run-flat tire specifications.
michelintruck.com/technical-data →Goodyear Technical Data
Commercial and passenger tire specifications, load tables, and engineering data. Excellent resource for truck and fleet tire information.
goodyear.com/technical-information →Bridgestone/Firestone Resources
Tire care guides, maintenance recommendations, and technical specifications for passenger, light truck, and specialty tires.
bridgestonetire.com/technical-info →Continental & Specialty Brands
European tire technical data, plus specialty manufacturers (BFGoodrich, Yokohama, Pirelli, Hankook) for performance, off-road, and EV-specific tire specifications.
Academic & Research References
📚 Tire Engineering Textbooks
- • "The Pneumatic Tire" - U.S. Department of Transportation
- • "Tire Technology" - Goodyear Technical Center publications
- • "Fundamentals of Vehicle Dynamics" - SAE International (Thomas Gillespie)
🔬 Automotive Engineering Journals
- • SAE International Technical Papers (tire dynamics, vehicle performance)
- • Journal of Automobile Engineering (tire-related research)
- • Tire Science and Technology Journal (academic tire research)
🏫 University Research
Tire and vehicle dynamics research from institutions including University of Michigan Transportation Research Institute (UMTRI), Virginia Tech, and technical universities worldwide conducting tire performance studies.
Data Update & Maintenance Schedule
📅 Quarterly Updates
Complete database review every 3 months to incorporate new vehicle models, updated tire specifications, and manufacturer changes. Includes TRA/ETRTO standard updates.
🔄 Real-Time Monitoring
Continuous monitoring of manufacturer websites, technical bulletins, and industry announcements for immediate critical updates (recalls, safety issues).
✅ Expert Review
All data changes undergo peer review by at least two team members. Safety-critical updates require ASE-certified technician approval before publication.
📝 Version Control
Complete audit trail of all data changes with timestamps, sources, and reviewer signatures. Ensures accountability and traceability.
Important Disclaimer
While TireSize.app strives for maximum accuracy using authoritative sources, tire fitment can be affected by variables beyond tire size alone, including:
- Suspension modifications (lifts, lowering kits, spacers)
- Wheel offset, backspacing, and width variations
- Vehicle load and alignment conditions
- Tire brand-specific sizing variations (±3% common)
- Manufacturer running changes and regional differences
Always consult with a professional tire technician before making final tire purchase decisions, especially for modified vehicles or unusual applications. TireSize.app provides guidance based on standard specifications, but professional verification ensures proper fitment for your specific vehicle.
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