guide
reading a tyre
In 90/90-18 51P, 90 is the width in millimetres, the second 90 is the sidewall height as a percentage of the width, the dash means bias construction (R is radial, B bias belted), and 18 is the rim diameter in inches.
- 01
51 is the load index: 195 kg per tyre. P is the speed symbol: 150 km/h. A replacement should have at least the stock load index and speed symbol.
- 02
Inch sizes such as 2.75-18 give the width in inches and have no profile number; 2.75 inches is about 70 mm.
- 03
TL means tubeless and TT tube type. The four digits at the end of the DOT code are the week and year it was made: 2325 is week 23 of 2025.
Source: ETRTO Standards Manual (tyre size, load index and speed symbol designations) – read it
Source: NHTSA: tire identification number and date code – read it