235/55R18 vs 255/50R18 tire size
255/50R18 vs 235/55R18, diameter
-0.5% shorter
- Speedometer
- 60.3 mph
- At a true 60 mph
- Diameter
- 28.04 in
- Was 28.18 in
- Revs per mile
- 719
- Was 716
- 3% guideline
- Within
Car built for 235/55R18, now on 255/50R18.
235/55R18 and 255/50R18
| Measure | 235/55R18 | 255/50R18 | Difference |
|---|---|---|---|
| Width, mm | 235 | 255 | +20 |
| Sidewall, % of width | 55 | 50 | -5 |
| Rim, in | 18 | 18 | 0 |
| Section height, in | 5.09 | 5.02 | -0.07 |
| Diameter, in | 28.18 | 28.04 | -0.14 (-0.5%) |
| Circumference, in | 88.5 | 88.1 | -0.4 |
| Revs per mile | 716 | 719 | +4 (+0.5%) |
Fitting 255/50R18 instead of 235/55R18
Within the usual 3% diameter guideline.
- 20 mm wider. Check rubbing at full lock.
Cars with 235/55R18
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