235/50R20 vs 265/40R21 tire size
265/40R21 vs 235/50R20, diameter
+0.3% taller
- Speedometer
- 59.8 mph
- At a true 60 mph
- Diameter
- 29.35 in
- Was 29.25 in
- Revs per mile
- 687
- Was 689
- 3% guideline
- Within
Car built for 235/50R20, now on 265/40R21.
235/50R20 and 265/40R21
| Measure | 235/50R20 | 265/40R21 | Difference |
|---|---|---|---|
| Width, mm | 235 | 265 | +30 |
| Sidewall, % of width | 50 | 40 | -10 |
| Rim, in | 20 | 21 | +1 |
| Section height, in | 4.63 | 4.17 | -0.45 |
| Diameter, in | 29.25 | 29.35 | +0.09 (+0.3%) |
| Circumference, in | 91.9 | 92.2 | +0.3 |
| Revs per mile | 689 | 687 | -2 (-0.3%) |
Fitting 265/40R21 instead of 235/50R20
Within the usual 3% diameter guideline.
- Needs 21 in wheels.
- 30 mm wider. Check rubbing at full lock.
Cars with 235/50R20
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