245/70R18 vs 255/65R18 tire size
255/65R18 vs 245/70R18, diameter
-1.4% shorter
- Speedometer
- 60.9 mph
- At a true 60 mph
- Diameter
- 31.05 in
- Was 31.50 in
- Revs per mile
- 650
- Was 640
- 3% guideline
- Within
Car built for 245/70R18, now on 255/65R18.
245/70R18 and 255/65R18
| Measure | 245/70R18 | 255/65R18 | Difference |
|---|---|---|---|
| Width, mm | 245 | 255 | +10 |
| Sidewall, % of width | 70 | 65 | -5 |
| Rim, in | 18 | 18 | 0 |
| Section height, in | 6.75 | 6.53 | -0.23 |
| Diameter, in | 31.50 | 31.05 | -0.45 (-1.4%) |
| Circumference, in | 99.0 | 97.6 | -1.4 |
| Revs per mile | 640 | 650 | +9 (+1.5%) |
Fitting 255/65R18 instead of 245/70R18
Within the usual 3% diameter guideline.
Cars with 245/70R18
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