275/40R20 vs 275/35R21 tire size
275/35R21 vs 275/40R20, diameter
-0.3% shorter
- Speedometer
- 60.2 mph
- At a true 60 mph
- Diameter
- 28.58 in
- Was 28.66 in
- Revs per mile
- 706
- Was 704
- 3% guideline
- Within
Car built for 275/40R20, now on 275/35R21.
275/40R20 and 275/35R21
| Measure | 275/40R20 | 275/35R21 | Difference |
|---|---|---|---|
| Width, mm | 275 | 275 | 0 |
| Sidewall, % of width | 40 | 35 | -5 |
| Rim, in | 20 | 21 | +1 |
| Section height, in | 4.33 | 3.79 | -0.54 |
| Diameter, in | 28.66 | 28.58 | -0.08 (-0.3%) |
| Circumference, in | 90.0 | 89.8 | -0.3 |
| Revs per mile | 704 | 706 | +2 (+0.3%) |
Fitting 275/35R21 instead of 275/40R20
Within the usual 3% diameter guideline.
- Needs 21 in wheels.
- Shorter sidewall: 0.5 in less.
Cars with 275/40R20
Cars with 275/35R21
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