205/50R17 vs 215/40R18 tire size
215/40R18 vs 205/50R17, diameter
-1.2% shorter
- Speedometer
- 60.7 mph
- At a true 60 mph
- Diameter
- 24.77 in
- Was 25.07 in
- Revs per mile
- 814
- Was 804
- 3% guideline
- Within
Car built for 205/50R17, now on 215/40R18.
205/50R17 and 215/40R18
| Measure | 205/50R17 | 215/40R18 | Difference |
|---|---|---|---|
| Width, mm | 205 | 215 | +10 |
| Sidewall, % of width | 50 | 40 | -10 |
| Rim, in | 17 | 18 | +1 |
| Section height, in | 4.04 | 3.39 | -0.65 |
| Diameter, in | 25.07 | 24.77 | -0.30 (-1.2%) |
| Circumference, in | 78.8 | 77.8 | -0.9 |
| Revs per mile | 804 | 814 | +10 (+1.2%) |
Fitting 215/40R18 instead of 205/50R17
Within the usual 3% diameter guideline.
- Needs 18 in wheels.
- Shorter sidewall: 0.6 in less.
Cars with 205/50R17
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