255/40R20 vs 265/35R21 tire size
265/35R21 vs 255/40R20, diameter
+1.0% taller
- Speedometer
- 59.4 mph
- At a true 60 mph
- Diameter
- 28.30 in
- Was 28.03 in
- Revs per mile
- 713
- Was 719
- 3% guideline
- Within
Car built for 255/40R20, now on 265/35R21.
255/40R20 and 265/35R21
| Measure | 255/40R20 | 265/35R21 | Difference |
|---|---|---|---|
| Width, mm | 255 | 265 | +10 |
| Sidewall, % of width | 40 | 35 | -5 |
| Rim, in | 20 | 21 | +1 |
| Section height, in | 4.02 | 3.65 | -0.36 |
| Diameter, in | 28.03 | 28.30 | +0.27 (+1.0%) |
| Circumference, in | 88.1 | 88.9 | +0.9 |
| Revs per mile | 719 | 713 | -7 (-1.0%) |
Fitting 265/35R21 instead of 255/40R20
Within the usual 3% diameter guideline.
- Needs 21 in wheels.
Cars with 255/40R20
Cars with 265/35R21
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