255/50R19 vs 285/40R20 tire size
285/40R20 vs 255/50R19, diameter
-0.2% shorter
- Speedometer
- 60.1 mph
- At a true 60 mph
- Diameter
- 28.98 in
- Was 29.04 in
- Revs per mile
- 696
- Was 695
- 3% guideline
- Within
Car built for 255/50R19, now on 285/40R20.
255/50R19 and 285/40R20
| Measure | 255/50R19 | 285/40R20 | Difference |
|---|---|---|---|
| Width, mm | 255 | 285 | +30 |
| Sidewall, % of width | 50 | 40 | -10 |
| Rim, in | 19 | 20 | +1 |
| Section height, in | 5.02 | 4.49 | -0.53 |
| Diameter, in | 29.04 | 28.98 | -0.06 (-0.2%) |
| Circumference, in | 91.2 | 91.0 | -0.2 |
| Revs per mile | 695 | 696 | +2 (+0.2%) |
Fitting 285/40R20 instead of 255/50R19
Within the usual 3% diameter guideline.
- Needs 20 in wheels.
- 30 mm wider. Check rubbing at full lock.
- Shorter sidewall: 0.5 in less.
Cars with 255/50R19
Cars with 285/40R20
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