215/45R18 vs 245/40R18 tire size
245/40R18 vs 215/45R18, diameter
+0.4% taller
- Speedometer
- 59.8 mph
- At a true 60 mph
- Diameter
- 25.72 in
- Was 25.62 in
- Revs per mile
- 784
- Was 787
- 3% guideline
- Within
Car built for 215/45R18, now on 245/40R18.
215/45R18 and 245/40R18
| Measure | 215/45R18 | 245/40R18 | Difference |
|---|---|---|---|
| Width, mm | 215 | 245 | +30 |
| Sidewall, % of width | 45 | 40 | -5 |
| Rim, in | 18 | 18 | 0 |
| Section height, in | 3.81 | 3.86 | +0.05 |
| Diameter, in | 25.62 | 25.72 | +0.10 (+0.4%) |
| Circumference, in | 80.5 | 80.8 | +0.3 |
| Revs per mile | 787 | 784 | -3 (-0.4%) |
Fitting 245/40R18 instead of 215/45R18
Within the usual 3% diameter guideline.
- 30 mm wider. Check rubbing at full lock.
Cars with 215/45R18
Cars with 245/40R18
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