245/75R17 vs 255/65R18 tire size
255/65R18 vs 245/75R17, diameter
-1.3% shorter
- Speedometer
- 60.8 mph
- At a true 60 mph
- Diameter
- 31.05 in
- Was 31.47 in
- Revs per mile
- 650
- Was 641
- 3% guideline
- Within
Car built for 245/75R17, now on 255/65R18.
245/75R17 and 255/65R18
| Measure | 245/75R17 | 255/65R18 | Difference |
|---|---|---|---|
| Width, mm | 245 | 255 | +10 |
| Sidewall, % of width | 75 | 65 | -10 |
| Rim, in | 17 | 18 | +1 |
| Section height, in | 7.23 | 6.53 | -0.71 |
| Diameter, in | 31.47 | 31.05 | -0.42 (-1.3%) |
| Circumference, in | 98.9 | 97.6 | -1.3 |
| Revs per mile | 641 | 650 | +9 (+1.3%) |
Fitting 255/65R18 instead of 245/75R17
Within the usual 3% diameter guideline.
- Needs 18 in wheels.
- Shorter sidewall: 0.7 in less.
Cars with 245/75R17
Cars with 255/65R18
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