255/65R17 vs 235/65R18 tire size
235/65R18 vs 255/65R17, diameter
Same diameter
- Speedometer
- 60.0 mph
- At a true 60 mph
- Diameter
- 30.03 in
- Was 30.05 in
- Revs per mile
- 672
- Was 671
- 3% guideline
- Within
Car built for 255/65R17, now on 235/65R18.
255/65R17 and 235/65R18
| Measure | 255/65R17 | 235/65R18 | Difference |
|---|---|---|---|
| Width, mm | 255 | 235 | -20 |
| Sidewall, % of width | 65 | 65 | 0 |
| Rim, in | 17 | 18 | +1 |
| Section height, in | 6.53 | 6.01 | -0.51 |
| Diameter, in | 30.05 | 30.03 | -0.02 (-0.1%) |
| Circumference, in | 94.4 | 94.3 | -0.1 |
| Revs per mile | 671 | 672 | +1 (+0.1%) |
Fitting 235/65R18 instead of 255/65R17
Within the usual 3% diameter guideline.
- Needs 18 in wheels.
- Shorter sidewall: 0.5 in less.
Cars with 255/65R17
Cars with 235/65R18
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