155/90R18 — what does it mean?
- 155 stands for tread width in millimeters
- 90 is an aspect ration between the tread width and the sidewall in percents
- R means that the tire has a radial construction
- 18 is a wheel diameter (or rim) in inches
How to convert 155 90R18 to inches?
First of all, we need to divide 155 mm (width) by 25.4 (mm to inch conversion), which will give us a width of 6.1″. Then, 90% of the 6.1″ will result in 5.5″ sidewall.
To get the total height or tire diameter, we need to sum the 18″ rim diameter with two of the sidewall heights. It will result in a 29″ total tire diameter (or height).
For your convenience, below is a table for 155/90R18 conversion to inches:
| Inches | Metric | |
|---|---|---|
| Overall diameter (height) | 29″ | 737 mm |
| Tread width | 6.1″ | 155 mm |
| Wheel diameter | 18″ | 737 mm |
| Sidewall height | 5.5″ | 140 mm |
| Circumference | 91.1″ | 2314 mm |
| Revolutions | 695 / ml | 432 / km |
Alternatives to a 155/90R18 tire
If you're looking to upsize your 155 90R18 tires, try to stay within 3% deviation of an overall diameter for safety reasons.
| Tire | Tire diameter | Width | Wheel Size |
|---|---|---|---|
| 265/55R18 | 29.4″ 0.34% | 10.4″ | 18″ |
| 255/55R18 | 29″ 0% | 10″ | 18″ |
| 295/45R18 | 28.4″ -0.55% | 11.6″ | 18″ |
| 235/60R18 | 29.2″ 0.17% | 9.3″ | 18″ |
| 245/60R18 | 29.6″ 0.5% | 9.6″ | 18″ |
| 225/60R18 | 28.6″ -0.38% | 8.9″ | 18″ |
| 245/55R18 | 28.6″ -0.38% | 9.6″ | 18″ |
| 155/85R18 | 28.4″ -0.55% | 6.1″ | 18″ |
| 165/90R18 | 29.8″ 0.67% | 6.5″ | 18″ |
| T175/80R18 | 29″ 0% | 6.9″ | 18″ |