285/40R21 vs 255/40R22 tire size
255/40R22 vs 285/40R21, diameter
+0.2% taller
- Speedometer
- 59.9 mph
- At a true 60 mph
- Diameter
- 30.03 in
- Was 29.98 in
- Revs per mile
- 672
- Was 673
- 3% guideline
- Within
Car built for 285/40R21, now on 255/40R22.
285/40R21 and 255/40R22
| Measure | 285/40R21 | 255/40R22 | Difference |
|---|---|---|---|
| Width, mm | 285 | 255 | -30 |
| Sidewall, % of width | 40 | 40 | 0 |
| Rim, in | 21 | 22 | +1 |
| Section height, in | 4.49 | 4.02 | -0.47 |
| Diameter, in | 29.98 | 30.03 | +0.06 (+0.2%) |
| Circumference, in | 94.2 | 94.3 | +0.2 |
| Revs per mile | 673 | 672 | -1 (-0.2%) |
Fitting 255/40R22 instead of 285/40R21
Within the usual 3% diameter guideline.
- Needs 22 in wheels.
Cars with 285/40R21
Cars with 255/40R22
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