Tire size formats

Tire Library accepts three notations. The search box parses them automatically.

Metric (passenger / light truck)

205/65R15
│  │  │ └── Rim diameter in inches (15)
│  │  └──── "R" = Radial construction
│  └─────── Aspect ratio = sidewall height as % of width (65 means 65%)
└────────── Width in millimeters (205 mm)

Imperial (commercial truck)

10R22.5
│ │  └── Rim diameter in inches, decimal allowed (22.5)
│ └──── "R" = Radial construction
└────── Width in inches (single or double digit, e.g. 9, 10, 11, 12)

Aspect ratio is 0 for imperial sizes.

Compact notation (truck sizes, shorthand)

10225     → 10R22.5
1022.5    → 10R22.5
819.5     → 8R19.5
1124.5    → 11R24.5

A 5-digit string starting with 8 or 9 is treated as single-digit-width compact imperial (819.5 → 8R19.5). Any other 5-digit string is treated as double-digit-width compact imperial (10225 → 10R22.5). A 7-digit string in the format XXX YY ZZ is parsed as metric (2056515 → 205/65R15).

How to enter in Tire Library

You type...	It searches for...
205/65/15 or 205/65R15	metric 205/65R15
10R22.5	imperial 10R22.5
10225 or 1022.5	imperial 10R22.5
michelin 205/65/15	make = michelin AND size = 205/65R15
michelin 10225	make = michelin AND size = 10R22.5