225/45R17 vs 215/40R18 tire size
215/40R18 vs 225/45R17, diameter
-0.8% shorter
- Speedometer
- 60.5 mph
- At a true 60 mph
- Diameter
- 24.77 in
- Was 24.97 in
- Revs per mile
- 814
- Was 808
- 3% guideline
- Within
Car built for 225/45R17, now on 215/40R18.
225/45R17 and 215/40R18
| Measure | 225/45R17 | 215/40R18 | Difference |
|---|---|---|---|
| Width, mm | 225 | 215 | -10 |
| Sidewall, % of width | 45 | 40 | -5 |
| Rim, in | 17 | 18 | +1 |
| Section height, in | 3.99 | 3.39 | -0.60 |
| Diameter, in | 24.97 | 24.77 | -0.20 (-0.8%) |
| Circumference, in | 78.5 | 77.8 | -0.6 |
| Revs per mile | 808 | 814 | +7 (+0.8%) |
Fitting 215/40R18 instead of 225/45R17
Within the usual 3% diameter guideline.
- Needs 18 in wheels.
- Shorter sidewall: 0.6 in less.
Cars with 225/45R17
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