245/75R18 vs 255/70R18 tire size
255/70R18 vs 245/75R18, diameter
-1.3% shorter
- Speedometer
- 60.8 mph
- At a true 60 mph
- Diameter
- 32.06 in
- Was 32.47 in
- Revs per mile
- 629
- Was 621
- 3% guideline
- Within
Car built for 245/75R18, now on 255/70R18.
245/75R18 and 255/70R18
| Measure | 245/75R18 | 255/70R18 | Difference |
|---|---|---|---|
| Width, mm | 245 | 255 | +10 |
| Sidewall, % of width | 75 | 70 | -5 |
| Rim, in | 18 | 18 | 0 |
| Section height, in | 7.23 | 7.03 | -0.21 |
| Diameter, in | 32.47 | 32.06 | -0.41 (-1.3%) |
| Circumference, in | 102.0 | 100.7 | -1.3 |
| Revs per mile | 621 | 629 | +8 (+1.3%) |
Fitting 255/70R18 instead of 245/75R18
Within the usual 3% diameter guideline.
Cars with 245/75R18
Cars with 255/70R18
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