245/40R21 vs 285/35R21 tire size
285/35R21 vs 245/40R21, diameter
+0.5% taller
- Speedometer
- 59.7 mph
- At a true 60 mph
- Diameter
- 28.85 in
- Was 28.72 in
- Revs per mile
- 699
- Was 702
- 3% guideline
- Within
Car built for 245/40R21, now on 285/35R21.
245/40R21 and 285/35R21
| Measure | 245/40R21 | 285/35R21 | Difference |
|---|---|---|---|
| Width, mm | 245 | 285 | +40 |
| Sidewall, % of width | 40 | 35 | -5 |
| Rim, in | 21 | 21 | 0 |
| Section height, in | 3.86 | 3.93 | +0.07 |
| Diameter, in | 28.72 | 28.85 | +0.14 (+0.5%) |
| Circumference, in | 90.2 | 90.6 | +0.4 |
| Revs per mile | 702 | 699 | -3 (-0.5%) |
Fitting 285/35R21 instead of 245/40R21
Within the usual 3% diameter guideline.
- 40 mm wider. Check rubbing at full lock.
Cars with 245/40R21
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