How to read your tire size
By XBRI Cubiertas · · Updated
Taking the size 265/70 R16 112T as an example:
Width
Section width in millimeters.
Aspect ratio
The ratio between the sidewall height and the width, as a percentage.
Construction type
«R» stands for radial, the standard on today's vehicles.
Rim diameter
Rim diameter in inches.
Load and speed indexes
The maximum load and maximum speed the tire can sustain.
What does the speed rating mean?
The speed index is the letter at the end of the tire size (for example, the «T» in 265/70 R16 112T). It indicates the maximum speed the tire can sustain under the load conditions specified by the manufacturer.
The table shows 29 speed ratings with their maximum speed in km/h and mph; the highlighted row is T, the speed rating of size 265/70 R16 112T.
| Rating | max. km/h | max. mph |
|---|---|---|
| A1 | 5 | 3 |
| A2 | 10 | 6 |
| A3 | 15 | 9 |
| A4 | 20 | 12 |
| A5 | 25 | 15 |
| A6 | 30 | 19 |
| A7 | 35 | 22 |
| A8 | 40 | 25 |
| B | 50 | 31 |
| C | 60 | 37 |
| D | 65 | 40 |
| E | 70 | 43 |
| F | 80 | 50 |
| G | 90 | 56 |
| J | 100 | 62 |
| K | 110 | 68 |
| L | 120 | 75 |
| M | 130 | 81 |
| N | 140 | 87 |
| P | 150 | 93 |
| Q | 160 | 100 |
| R | 170 | 106 |
| S | 180 | 113 |
| T | 190 | 118 |
| H | 210 | 130 |
| V | 240 | 150 |
| W | 270 | 168 |
| Y | 300 | 186 |
| ZR | 240+ | 149+ |
Never use a tire with a speed index lower than the one specified by the vehicle manufacturer. The correct information is in the owner's manual and, usually, on the driver's door frame.
What does the load index mean?
The load index is the number right before the speed index (the «112» in 265/70 R16 112T). It indicates the maximum load each tire can carry.
The grid shows 71 load indexes, from 60 to 130, with the weight in kg each tire can carry; the highlighted one is 112, the load index of size 265/70 R16 112T.
Index · kg per tire
The total loaded weight of the vehicle must not exceed the combined capacity of the four tires.
How do you check your tire?
Check the tread
The tread has a wear indicator (TWI). Check it at two or more points on the tire. Once the tread reaches the indicator, the tire must be replaced.
Checking the pressure keeps you safe
Besides checking the tread, tire pressure is another factor to keep in mind. The right pressure means less wear and more efficient fuel use.
What is the correct tire pressure?
When should it be checked?
- Once a month
- With cold tires
- Before long trips
- When carrying heavy loads
Where to check the recommended pressure?
Inside the vehicle (fuel cap, door jamb or glovebox) and in the owner's manual.
Why should it be checked?
- To avoid uneven wear
- Safety
- Excess fuel consumption