205/50R17 vs 225/40R18 tire size
225/40R18 vs 205/50R17, diameter
Same diameter
- Speedometer
- 60.0 mph
- At a true 60 mph
- Diameter
- 25.09 in
- Was 25.07 in
- Revs per mile
- 804
- Was 804
- 3% guideline
- Within
Car built for 205/50R17, now on 225/40R18.
205/50R17 and 225/40R18
| Measure | 205/50R17 | 225/40R18 | Difference |
|---|---|---|---|
| Width, mm | 205 | 225 | +20 |
| Sidewall, % of width | 50 | 40 | -10 |
| Rim, in | 17 | 18 | +1 |
| Section height, in | 4.04 | 3.54 | -0.49 |
| Diameter, in | 25.07 | 25.09 | +0.02 (+0.1%) |
| Circumference, in | 78.8 | 78.8 | +0.0 |
| Revs per mile | 804 | 804 | -1 (-0.1%) |
Fitting 225/40R18 instead of 205/50R17
Within the usual 3% diameter guideline.
- Needs 18 in wheels.
- 20 mm wider. Check rubbing at full lock.
Cars with 205/50R17
Cars with 225/40R18
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