235/55R20 vs 285/45R20 tire size
285/45R20 vs 235/55R20, diameter
-0.3% shorter
- Speedometer
- 60.2 mph
- At a true 60 mph
- Diameter
- 30.10 in
- Was 30.18 in
- Revs per mile
- 670
- Was 668
- 3% guideline
- Within
Car built for 235/55R20, now on 285/45R20.
235/55R20 and 285/45R20
| Measure | 235/55R20 | 285/45R20 | Difference |
|---|---|---|---|
| Width, mm | 235 | 285 | +50 |
| Sidewall, % of width | 55 | 45 | -10 |
| Rim, in | 20 | 20 | 0 |
| Section height, in | 5.09 | 5.05 | -0.04 |
| Diameter, in | 30.18 | 30.10 | -0.08 (-0.3%) |
| Circumference, in | 94.8 | 94.6 | -0.2 |
| Revs per mile | 668 | 670 | +2 (+0.3%) |
Fitting 285/45R20 instead of 235/55R20
Within the usual 3% diameter guideline.
- 50 mm wider. Check rubbing at full lock.
Cars with 235/55R20
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