285/45R20 vs 295/40R21 tire size
295/40R21 vs 285/45R20, diameter
+0.6% taller
- Speedometer
- 59.6 mph
- At a true 60 mph
- Diameter
- 30.29 in
- Was 30.10 in
- Revs per mile
- 666
- Was 670
- 3% guideline
- Within
Car built for 285/45R20, now on 295/40R21.
285/45R20 and 295/40R21
| Measure | 285/45R20 | 295/40R21 | Difference |
|---|---|---|---|
| Width, mm | 285 | 295 | +10 |
| Sidewall, % of width | 45 | 40 | -5 |
| Rim, in | 20 | 21 | +1 |
| Section height, in | 5.05 | 4.65 | -0.40 |
| Diameter, in | 30.10 | 30.29 | +0.19 (+0.6%) |
| Circumference, in | 94.6 | 95.2 | +0.6 |
| Revs per mile | 670 | 666 | -4 (-0.6%) |
Fitting 295/40R21 instead of 285/45R20
Within the usual 3% diameter guideline.
- Needs 21 in wheels.
Cars with 285/45R20
Cars with 295/40R21
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