255/50R20 vs 285/45R20 tire size
285/45R20 vs 255/50R20, diameter
+0.2% taller
- Speedometer
- 59.9 mph
- At a true 60 mph
- Diameter
- 30.10 in
- Was 30.04 in
- Revs per mile
- 670
- Was 671
- 3% guideline
- Within
Car built for 255/50R20, now on 285/45R20.
255/50R20 and 285/45R20
| Measure | 255/50R20 | 285/45R20 | Difference |
|---|---|---|---|
| Width, mm | 255 | 285 | +30 |
| Sidewall, % of width | 50 | 45 | -5 |
| Rim, in | 20 | 20 | 0 |
| Section height, in | 5.02 | 5.05 | +0.03 |
| Diameter, in | 30.04 | 30.10 | +0.06 (+0.2%) |
| Circumference, in | 94.4 | 94.6 | +0.2 |
| Revs per mile | 671 | 670 | -1 (-0.2%) |
Fitting 285/45R20 instead of 255/50R20
Within the usual 3% diameter guideline.
- 30 mm wider. Check rubbing at full lock.
Cars with 255/50R20
Cars with 285/45R20
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