265/45R20 vs 265/40R21 tire size
265/40R21 vs 265/45R20, diameter
-0.1% shorter
- Speedometer
- 60.1 mph
- At a true 60 mph
- Diameter
- 29.35 in
- Was 29.39 in
- Revs per mile
- 687
- Was 686
- 3% guideline
- Within
Car built for 265/45R20, now on 265/40R21.
265/45R20 and 265/40R21
| Measure | 265/45R20 | 265/40R21 | Difference |
|---|---|---|---|
| Width, mm | 265 | 265 | 0 |
| Sidewall, % of width | 45 | 40 | -5 |
| Rim, in | 20 | 21 | +1 |
| Section height, in | 4.69 | 4.17 | -0.52 |
| Diameter, in | 29.39 | 29.35 | -0.04 (-0.1%) |
| Circumference, in | 92.3 | 92.2 | -0.1 |
| Revs per mile | 686 | 687 | +1 (+0.1%) |
Fitting 265/40R21 instead of 265/45R20
Within the usual 3% diameter guideline.
- Needs 21 in wheels.
- Shorter sidewall: 0.5 in less.
Cars with 265/45R20
Cars with 265/40R21
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