Tire Ruler225/60R18 dimensions
| Overall diameter (height) | 28.63″ · 727 mm |
| Section width | 8.86″ · 225 mm |
| Sidewall height | 5.31″ · 135 mm |
| Wheel diameter | 18″ |
| Rim width (rule of thumb) | 6–8″ |
| Circumference | 89.9″ |
| Revolutions per mile | 704 |
| In inches (flotation style) | 28.6 × 8.9R18 |
How it’s calculated: the sidewall is 60% of the 225 mm width = 135.0 mm (5.31″). Add two sidewalls to the 18″ wheel: 18 + 2 × 5.31 = 28.63″.
Bigger tires than 225/60R18 on 18″ wheels
| Size | Height | Taller by | 60 mph reads |
|---|---|---|---|
| 255/55R18 | 29.0″ | +0.41″ (+1.4%) | 60.9 mph |
| 235/60R18 | 29.1″ | +0.47″ (+1.7%) | 61.0 mph |
| 245/60R18 | 29.6″ | +0.94″ (+3.3%) | 62.0 mph |
| 235/65R18 | 30.0″ | +1.40″ (+4.9%) | 62.9 mph |
| 265/60R18 | 30.5″ | +1.89″ (+6.6%) | 64.0 mph |
“60 mph reads” is your real speed when a speedometer set up for 225/60R18 shows 60. Above about 3% taller, most trucks need a leveling kit or lift, and the speedometer should be recalibrated.
Sizes equivalent to 225/60R18
Within 1.5% of the same height on an 18″ wheel. Usually interchangeable for the speedometer; check width, load index and clearance.
| Size | Height | Width | Difference |
|---|---|---|---|
| 255/55R18 | 29.0″ | 10.0″ | +1.4% |
Same height on a different wheel size
Changing wheel size (plus or minus sizing) while keeping the overall height keeps your speedometer right:
- 235/75R15: 28.9″ tall on a 15″ wheel (+0.9%)
- 225/75R15: 28.3″ tall on a 15″ wheel (−1.2%)
- 235/70R16: 29.0″ tall on a 16″ wheel (+1.1%)
- 225/70R16: 28.4″ tall on a 16″ wheel (−0.8%)
- 235/65R17: 29.0″ tall on a 17″ wheel (+1.4%)
- 225/65R17: 28.5″ tall on a 17″ wheel (−0.4%)
- 255/50R19: 29.0″ tall on a 19″ wheel (+1.4%)
- 255/45R20: 29.0″ tall on a 20″ wheel (+1.4%)
- 245/45R20: 28.7″ tall on a 20″ wheel (+0.2%)
- 275/40R20: 28.7″ tall on a 20″ wheel (+0.1%)
Frequently asked questions
Is 225/60R18 a 29 inch tire?
Not quite. 225/60R18 is 28.63 inches tall, between a 28 and a 29 inch tire.
What size is 225/60R18 in inches?
225/60R18 is 28.6 inches tall (overall diameter), 8.9 inches wide, with a 5.3 inch sidewall, and fits an 18 inch wheel.
What tire size is equivalent to 225/60R18?
Sizes within 1.5% of the same diameter on an 18" wheel: 255/55R18 (29.0"). Check load index and width before swapping.
What rim width fits 225/60R18?
As a rule of thumb, about 6–8 inches. The tire maker's spec sheet lists the approved range for each model.
How many revolutions per mile does 225/60R18 make?
About 704 revolutions per mile in theory (circumference 89.9 in). Real tires turn slightly more because they flatten under load.