215/70R17 vs 255/55R18 tire size
255/55R18 vs 215/70R17, diameter
+0.7% taller
- Speedometer
- 59.6 mph
- At a true 60 mph
- Diameter
- 29.04 in
- Was 28.85 in
- Revs per mile
- 694
- Was 699
- 3% guideline
- Within
Car built for 215/70R17, now on 255/55R18.
215/70R17 and 255/55R18
| Measure | 215/70R17 | 255/55R18 | Difference |
|---|---|---|---|
| Width, mm | 215 | 255 | +40 |
| Sidewall, % of width | 70 | 55 | -15 |
| Rim, in | 17 | 18 | +1 |
| Section height, in | 5.93 | 5.52 | -0.40 |
| Diameter, in | 28.85 | 29.04 | +0.19 (+0.7%) |
| Circumference, in | 90.6 | 91.2 | +0.6 |
| Revs per mile | 699 | 694 | -5 (-0.7%) |
Fitting 255/55R18 instead of 215/70R17
Within the usual 3% diameter guideline.
- Needs 18 in wheels.
- 40 mm wider. Check rubbing at full lock.
Cars with 255/55R18
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