275/35R20 vs 245/35R21 tire size
245/35R21 vs 275/35R20, diameter
+0.6% taller
- Speedometer
- 59.6 mph
- At a true 60 mph
- Diameter
- 27.75 in
- Was 27.58 in
- Revs per mile
- 727
- Was 731
- 3% guideline
- Within
Car built for 275/35R20, now on 245/35R21.
275/35R20 and 245/35R21
| Measure | 275/35R20 | 245/35R21 | Difference |
|---|---|---|---|
| Width, mm | 275 | 245 | -30 |
| Sidewall, % of width | 35 | 35 | 0 |
| Rim, in | 20 | 21 | +1 |
| Section height, in | 3.79 | 3.38 | -0.41 |
| Diameter, in | 27.58 | 27.75 | +0.17 (+0.6%) |
| Circumference, in | 86.6 | 87.2 | +0.5 |
| Revs per mile | 731 | 727 | -5 (-0.6%) |
Fitting 245/35R21 instead of 275/35R20
Within the usual 3% diameter guideline.
- Needs 21 in wheels.
Cars with 275/35R20
Cars with 245/35R21
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