Tire basics, explained quickly.

Short answers with sources. These guides will later become the semantic foundation of RideVector’s fitment and product data.

Last updated: September 2026

How to read a tire size such as 225/45 R18 91W: section width, aspect ratio, construction, rim diameter, load index and speed symbol.

Original sizes, approved alternatives, rim-width ranges and the load and speed requirements a replacement tire must meet.

What the load index means and the full load index to kilograms table.

What the speed symbol means, the full symbol to km/h table, and how ZR and (Y) notation work.

Definitions, the difference between M+S and the 3PMSF Alpine symbol, and winter-tire rules across European markets.

What changes for tires on EVs: load, torque and wear, rolling resistance and range, noise, and manufacturer EV ranges.

Regulation (EU) 2020/740: fuel efficiency, wet grip and noise classes, snow and ice pictograms, EPREL and the QR code.