225/55R17 vs 275/40R18 tire size
275/40R18 vs 225/55R17, diameter
-0.3% shorter
- Speedometer
- 60.2 mph
- At a true 60 mph
- Diameter
- 26.66 in
- Was 26.74 in
- Revs per mile
- 756
- Was 754
- 3% guideline
- Within
Car built for 225/55R17, now on 275/40R18.
225/55R17 and 275/40R18
| Measure | 225/55R17 | 275/40R18 | Difference |
|---|---|---|---|
| Width, mm | 225 | 275 | +50 |
| Sidewall, % of width | 55 | 40 | -15 |
| Rim, in | 17 | 18 | +1 |
| Section height, in | 4.87 | 4.33 | -0.54 |
| Diameter, in | 26.74 | 26.66 | -0.08 (-0.3%) |
| Circumference, in | 84.0 | 83.8 | -0.3 |
| Revs per mile | 754 | 756 | +2 (+0.3%) |
Fitting 275/40R18 instead of 225/55R17
Within the usual 3% diameter guideline.
- Needs 18 in wheels.
- 50 mm wider. Check rubbing at full lock.
- Shorter sidewall: 0.5 in less.
Cars with 225/55R17
Cars with 275/40R18
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