225/40R18 vs 255/30R19 tire size
255/30R19 vs 225/40R18, diameter
-0.3% shorter
- Speedometer
- 60.2 mph
- At a true 60 mph
- Diameter
- 25.02 in
- Was 25.09 in
- Revs per mile
- 806
- Was 804
- 3% guideline
- Within
Car built for 225/40R18, now on 255/30R19.
225/40R18 and 255/30R19
| Measure | 225/40R18 | 255/30R19 | Difference |
|---|---|---|---|
| Width, mm | 225 | 255 | +30 |
| Sidewall, % of width | 40 | 30 | -10 |
| Rim, in | 18 | 19 | +1 |
| Section height, in | 3.54 | 3.01 | -0.53 |
| Diameter, in | 25.09 | 25.02 | -0.06 (-0.3%) |
| Circumference, in | 78.8 | 78.6 | -0.2 |
| Revs per mile | 804 | 806 | +2 (+0.3%) |
Fitting 255/30R19 instead of 225/40R18
Within the usual 3% diameter guideline.
- Needs 19 in wheels.
- 30 mm wider. Check rubbing at full lock.
- Shorter sidewall: 0.5 in less.
Cars with 225/40R18
Cars with 255/30R19
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