What does 305/45R18 mean?
305/45R18 is a tire size with the following dimensions:
- 305 is the width of the tire in millimeters. This number also indicates the appropriate width of the rim on which the tire should be mounted.
- 45 is the aspect ratio, which is the ratio of the tire's height to its width. This affects the tire's handling and ride comfort
- R indicates the tire's construction type, meaning it has a radial construction. This provides stability and precision to the tire.
- 18 is the diameter of the wheel in inches, on which the tire is to be mounted.
305/45R18 Tire Conversion
| Dimensions | Inches | Millimeters |
| Tire Diameter | 28.8 in | 731.7 mm |
| Section Width | 12 in | 305 mm |
| Rim Height | 18 in | 457 mm |
| Sidewall Height | 5.4 in | 137.3 mm |
| Circumference | 90.5 in | 2298.7 mm |
| Revolutions | 700.1 revs/mile | |
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FAQ About 305/45R18 Tire
How tall is a 305/45R18 tire?
The height (or diameter) of a 305/45R18 tire is 28.8 inches
How wide is a 305/45R18 tire?
The width of a 305/45R18 tire is 305 mm, which is about 12 inches.
What size rim fits a 305/45R18 tire?
A 305/45R18 tire fits on a rim that is 18 inches in diameter.
What does the 45 in a 305/45R18 tire mean?
The 45 in a 305/45R18 tire refers to the aspect ratio, meaning the height of the tire's sidewall is 45% of its width.
Alternative Tire Sizes for 305/45R18
Typically, it's recommended to choose a tire with a diameter (height) within 3% of the original equipment manufacturer (OEM) tire size.
However, keep in mind that this is a general guideline and not an absolute rule.
Here are some tire sizes that are compatible with the 305/45R18:
| Tire Size | Diameter | Rim |
|---|---|---|
| 275/50R18 | 28.8″ (Equal) | 18 x 7.5-9.5 |
| 155/85R18 | 28.4″ (-1.4%) | 18 x n/a |
| 155/90R18 | 29.0″ (0.7%) | 18 x n/a |
| 175/80R18 | 29.0″ (0.7%) | 18 x n/a |
| 225/60R18 | 28.6″ (-0.7%) | 18 x 6.0-8.0 |
| 225/65R18 | 29.5″ (2.4%) | 18 x 6.0-8.0 |
| 235/55R18 | 28.2″ (-2.1%) | 18 x 6.5-8.5 |
| 235/60R18 | 29.1″ (1.0%) | 18 x 6.5-8.5 |
| 245/55R18 | 28.6″ (-0.7%) | 18 x 7.0-8.5 |
| 245/60R18 | 29.6″ (2.8%) | 18 x 7.0-8.5 |
| 255/50R18 | 28.0″ (-2.8%) | 18 x 7.0-9.0 |
| 255/55R18 | 29.0″ (0.7%) | 18 x 7.0-9.0 |
| 265/50R18 | 28.4″ (-1.4%) | 18 x 7.5-9.5 |
| 265/55R18 | 29.5″ (2.4%) | 18 x 7.5-9.5 |
| 285/45R18 | 28.1″ (-2.4%) | 18 x 9.0-10.5 |
| 285/50R18 | 29.2″ (1.4%) | 18 x 8.0-10.0 |
| 295/45R18 | 28.5″ (-1.0%) | 18 x 9.5-11.0 |
| 325/45R18 | 29.5″ (2.4%) | 18 x n/a |