295/45R20 vs 295/40R21 tire size
295/40R21 vs 295/45R20, diameter
-0.5% shorter
- Speedometer
- 60.3 mph
- At a true 60 mph
- Diameter
- 30.29 in
- Was 30.45 in
- Revs per mile
- 666
- Was 662
- 3% guideline
- Within
Car built for 295/45R20, now on 295/40R21.
295/45R20 and 295/40R21
| Measure | 295/45R20 | 295/40R21 | Difference |
|---|---|---|---|
| Width, mm | 295 | 295 | 0 |
| Sidewall, % of width | 45 | 40 | -5 |
| Rim, in | 20 | 21 | +1 |
| Section height, in | 5.23 | 4.65 | -0.58 |
| Diameter, in | 30.45 | 30.29 | -0.16 (-0.5%) |
| Circumference, in | 95.7 | 95.2 | -0.5 |
| Revs per mile | 662 | 666 | +4 (+0.5%) |
Fitting 295/40R21 instead of 295/45R20
Within the usual 3% diameter guideline.
- Needs 21 in wheels.
- Shorter sidewall: 0.6 in less.
Cars with 295/45R20
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