225/55R17 vs 245/45R18 tire size
245/45R18 vs 225/55R17, diameter
-0.2% shorter
- Speedometer
- 60.1 mph
- At a true 60 mph
- Diameter
- 26.68 in
- Was 26.74 in
- Revs per mile
- 756
- Was 754
- 3% guideline
- Within
Car built for 225/55R17, now on 245/45R18.
225/55R17 and 245/45R18
| Measure | 225/55R17 | 245/45R18 | Difference |
|---|---|---|---|
| Width, mm | 225 | 245 | +20 |
| Sidewall, % of width | 55 | 45 | -10 |
| Rim, in | 17 | 18 | +1 |
| Section height, in | 4.87 | 4.34 | -0.53 |
| Diameter, in | 26.74 | 26.68 | -0.06 (-0.2%) |
| Circumference, in | 84.0 | 83.8 | -0.2 |
| Revs per mile | 754 | 756 | +2 (+0.2%) |
Fitting 245/45R18 instead of 225/55R17
Within the usual 3% diameter guideline.
- Needs 18 in wheels.
- 20 mm wider. Check rubbing at full lock.
- Shorter sidewall: 0.5 in less.
Cars with 225/55R17
Cars with 245/45R18
What this cannot tell you
Diameter within 3% is a common shop guideline, not a maker spec.
Load index, offset and clearance are not in this data.
- Two or more sources agree
- One source
- Model-level or estimate
- Sources differ