215/45R17 vs 215/40R18 tire size
215/40R18 vs 215/45R17, diameter
+0.6% taller
- Speedometer
- 59.6 mph
- At a true 60 mph
- Diameter
- 24.77 in
- Was 24.62 in
- Revs per mile
- 814
- Was 819
- 3% guideline
- Within
Car built for 215/45R17, now on 215/40R18.
215/45R17 and 215/40R18
| Measure | 215/45R17 | 215/40R18 | Difference |
|---|---|---|---|
| Width, mm | 215 | 215 | 0 |
| Sidewall, % of width | 45 | 40 | -5 |
| Rim, in | 17 | 18 | +1 |
| Section height, in | 3.81 | 3.39 | -0.42 |
| Diameter, in | 24.62 | 24.77 | +0.15 (+0.6%) |
| Circumference, in | 77.3 | 77.8 | +0.5 |
| Revs per mile | 819 | 814 | -5 (-0.6%) |
Fitting 215/40R18 instead of 215/45R17
Within the usual 3% diameter guideline.
- Needs 18 in wheels.
Cars with 215/45R17
Cars with 215/40R18
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