What does 285/40R21 mean?
|
285 |
The tire width is 285mm. |
|
40 |
The aspect ratio of the tire is 40. Aspect ratio is the relative height of tire sidewall. The number refers to the percentage of sidewall height in relation to tire width. |
|
R |
The letter in the middle refers to tire construction. Practically all tires sold for cars are radials.
Sometimes you also see tires with RF or ZR. RF indicates the tire is run flat, whereas ZR means the tire has speed rating higher than V. These tires are also radials, as the R indicates. |
|
21 |
Rim diameter for the tire. |
285/40R21 109H tire size
The width of 285/40R21 109H tire is stated in millimeters and sidewall height in percentages. In this table you’ll find out the 285/40R21 109H tire size in inches as well as few additional metrics:
|
|
In inches | In millimeters |
|
Section Width |
11.2″ | 285mm |
|
Sidewall height |
4.5″ | 114mm |
|
Diameter / Height |
30.0″ | 761mm |
|
Circumference |
94.2″ | 2392mm |
|
Rim Diameter |
21″ | |
|
Revolutions |
673 per mile | 418 per kilometer |
Rim Size for 285/40R21 109H Tires
Recommended rim sizes for 285/40R21 109H tire:
| Diameter | Width Range |
| 21″ | 9.5-11″ |
What does 109H mean?
The load index 109 means that the tire has been designed to support 2271 lbs or 1030 kg.
The speed index H means that the tire has been designed to be used in speed up to 130 mph or 210 kph.
This size tire is usually used on high-performance vehicles.