255/55R20 vs 285/50R20 tire size
285/50R20 vs 255/55R20, diameter
+0.6% taller
- Speedometer
- 59.7 mph
- At a true 60 mph
- Diameter
- 31.22 in
- Was 31.04 in
- Revs per mile
- 646
- Was 650
- 3% guideline
- Within
Car built for 255/55R20, now on 285/50R20.
255/55R20 and 285/50R20
| Measure | 255/55R20 | 285/50R20 | Difference |
|---|---|---|---|
| Width, mm | 255 | 285 | +30 |
| Sidewall, % of width | 55 | 50 | -5 |
| Rim, in | 20 | 20 | 0 |
| Section height, in | 5.52 | 5.61 | +0.09 |
| Diameter, in | 31.04 | 31.22 | +0.18 (+0.6%) |
| Circumference, in | 97.5 | 98.1 | +0.6 |
| Revs per mile | 650 | 646 | -4 (-0.6%) |
Fitting 285/50R20 instead of 255/55R20
Within the usual 3% diameter guideline.
- 30 mm wider. Check rubbing at full lock.
Cars with 255/55R20
Cars with 285/50R20
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