255/45R20 vs 295/35R21 tire size
295/35R21 vs 255/45R20, diameter
+0.3% taller
- Speedometer
- 59.8 mph
- At a true 60 mph
- Diameter
- 29.13 in
- Was 29.04 in
- Revs per mile
- 692
- Was 695
- 3% guideline
- Within
Car built for 255/45R20, now on 295/35R21.
255/45R20 and 295/35R21
| Measure | 255/45R20 | 295/35R21 | Difference |
|---|---|---|---|
| Width, mm | 255 | 295 | +40 |
| Sidewall, % of width | 45 | 35 | -10 |
| Rim, in | 20 | 21 | +1 |
| Section height, in | 4.52 | 4.06 | -0.45 |
| Diameter, in | 29.04 | 29.13 | +0.09 (+0.3%) |
| Circumference, in | 91.2 | 91.5 | +0.3 |
| Revs per mile | 695 | 692 | -2 (-0.3%) |
Fitting 295/35R21 instead of 255/45R20
Within the usual 3% diameter guideline.
- Needs 21 in wheels.
- 40 mm wider. Check rubbing at full lock.
Cars with 255/45R20
Cars with 295/35R21
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