255/35R20 vs 285/30R20 tire size
285/30R20 vs 255/35R20, diameter
-1.1% shorter
- Speedometer
- 60.7 mph
- At a true 60 mph
- Diameter
- 26.73 in
- Was 27.03 in
- Revs per mile
- 754
- Was 746
- 3% guideline
- Within
Car built for 255/35R20, now on 285/30R20.
255/35R20 and 285/30R20
| Measure | 255/35R20 | 285/30R20 | Difference |
|---|---|---|---|
| Width, mm | 255 | 285 | +30 |
| Sidewall, % of width | 35 | 30 | -5 |
| Rim, in | 20 | 20 | 0 |
| Section height, in | 3.51 | 3.37 | -0.15 |
| Diameter, in | 27.03 | 26.73 | -0.30 (-1.1%) |
| Circumference, in | 84.9 | 84.0 | -0.9 |
| Revs per mile | 746 | 754 | +8 (+1.1%) |
Fitting 285/30R20 instead of 255/35R20
Within the usual 3% diameter guideline.
- 30 mm wider. Check rubbing at full lock.
Cars with 255/35R20
Cars with 285/30R20
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