255/65R17 vs 275/55R18 tire size
275/55R18 vs 255/65R17, diameter
-0.5% shorter
- Speedometer
- 60.3 mph
- At a true 60 mph
- Diameter
- 29.91 in
- Was 30.05 in
- Revs per mile
- 674
- Was 671
- 3% guideline
- Within
Car built for 255/65R17, now on 275/55R18.
255/65R17 and 275/55R18
| Measure | 255/65R17 | 275/55R18 | Difference |
|---|---|---|---|
| Width, mm | 255 | 275 | +20 |
| Sidewall, % of width | 65 | 55 | -10 |
| Rim, in | 17 | 18 | +1 |
| Section height, in | 6.53 | 5.95 | -0.57 |
| Diameter, in | 30.05 | 29.91 | -0.14 (-0.5%) |
| Circumference, in | 94.4 | 94.0 | -0.4 |
| Revs per mile | 671 | 674 | +3 (+0.5%) |
Fitting 275/55R18 instead of 255/65R17
Within the usual 3% diameter guideline.
- Needs 18 in wheels.
- 20 mm wider. Check rubbing at full lock.
- Shorter sidewall: 0.6 in less.
Cars with 255/65R17
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