Tire Tools
Tire Tools
Free calculators for fleet managers, operations teams and drivers. Decode a tire size, compare an alternative size, and check tire age and tread depth.
Tire Size Calculator
Sidewall height, overall diameter, circumference and revolutions per km from the size code. Compare an alternative size: diameter difference, speedometer deviation, load and speed index.
Tire Age (DOT)
Production week, date and tire age from the last four digits of the DOT code on the sidewall, assessed against the 5- and 10-year thresholds.
Tread Depth
Assess your measured tread depth against the legal minimum and the recommended replacement threshold for the season.
Load & Speed Index
Complete load index (50-170) and speed rating (A1-Y) tables for passenger, light commercial and heavy vehicles.
Why these tools?
The wrong size, a low load index or an aged tire affects every line of a fleet's costs, from fuel consumption and braking distance to vehicle downtime and insurance.
These tools help you base tire decisions on measurement rather than guesswork. Calculations run in your browser; nothing you enter is stored.
For your fleet
Move tire operations from calculation to management
Tire changes, tire hotel storage, mobile service and the ZyTire digital fleet platform: manage your fleet's entire tire cycle with a single partner.