235/70R17 vs 255/60R18 tire size
255/60R18 vs 235/70R17, diameter
+0.3% taller
- Speedometer
- 59.8 mph
- At a true 60 mph
- Diameter
- 30.05 in
- Was 29.95 in
- Revs per mile
- 671
- Was 673
- 3% guideline
- Within
Car built for 235/70R17, now on 255/60R18.
235/70R17 and 255/60R18
| Measure | 235/70R17 | 255/60R18 | Difference |
|---|---|---|---|
| Width, mm | 235 | 255 | +20 |
| Sidewall, % of width | 70 | 60 | -10 |
| Rim, in | 17 | 18 | +1 |
| Section height, in | 6.48 | 6.02 | -0.45 |
| Diameter, in | 29.95 | 30.05 | +0.09 (+0.3%) |
| Circumference, in | 94.1 | 94.4 | +0.3 |
| Revs per mile | 673 | 671 | -2 (-0.3%) |
Fitting 255/60R18 instead of 235/70R17
Within the usual 3% diameter guideline.
- Needs 18 in wheels.
- 20 mm wider. Check rubbing at full lock.
Cars with 255/60R18
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