235/65R17 vs 245/55R18 tire size
245/55R18 vs 235/65R17, diameter
-1.4% shorter
- Speedometer
- 60.9 mph
- At a true 60 mph
- Diameter
- 28.61 in
- Was 29.03 in
- Revs per mile
- 705
- Was 695
- 3% guideline
- Within
Car built for 235/65R17, now on 245/55R18.
235/65R17 and 245/55R18
| Measure | 235/65R17 | 245/55R18 | Difference |
|---|---|---|---|
| Width, mm | 235 | 245 | +10 |
| Sidewall, % of width | 65 | 55 | -10 |
| Rim, in | 17 | 18 | +1 |
| Section height, in | 6.01 | 5.31 | -0.71 |
| Diameter, in | 29.03 | 28.61 | -0.42 (-1.4%) |
| Circumference, in | 91.2 | 89.9 | -1.3 |
| Revs per mile | 695 | 705 | +10 (+1.5%) |
Fitting 245/55R18 instead of 235/65R17
Within the usual 3% diameter guideline.
- Needs 18 in wheels.
- Shorter sidewall: 0.7 in less.
Cars with 235/65R17
Cars with 245/55R18
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