255/70R17 vs 285/60R18 tire size
285/60R18 vs 255/70R17, diameter
+1.3% taller
- Speedometer
- 59.2 mph
- At a true 60 mph
- Diameter
- 31.46 in
- Was 31.06 in
- Revs per mile
- 641
- Was 649
- 3% guideline
- Within
Car built for 255/70R17, now on 285/60R18.
255/70R17 and 285/60R18
| Measure | 255/70R17 | 285/60R18 | Difference |
|---|---|---|---|
| Width, mm | 255 | 285 | +30 |
| Sidewall, % of width | 70 | 60 | -10 |
| Rim, in | 17 | 18 | +1 |
| Section height, in | 7.03 | 6.73 | -0.30 |
| Diameter, in | 31.06 | 31.46 | +0.41 (+1.3%) |
| Circumference, in | 97.6 | 98.8 | +1.3 |
| Revs per mile | 649 | 641 | -8 (-1.3%) |
Fitting 285/60R18 instead of 255/70R17
Within the usual 3% diameter guideline.
- Needs 18 in wheels.
- 30 mm wider. Check rubbing at full lock.
Cars with 255/70R17
Cars with 285/60R18
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