235/80R17 vs 245/70R18 tire size
245/70R18 vs 235/80R17, diameter
-0.9% shorter
- Speedometer
- 60.6 mph
- At a true 60 mph
- Diameter
- 31.50 in
- Was 31.80 in
- Revs per mile
- 640
- Was 634
- 3% guideline
- Within
Car built for 235/80R17, now on 245/70R18.
235/80R17 and 245/70R18
| Measure | 235/80R17 | 245/70R18 | Difference |
|---|---|---|---|
| Width, mm | 235 | 245 | +10 |
| Sidewall, % of width | 80 | 70 | -10 |
| Rim, in | 17 | 18 | +1 |
| Section height, in | 7.40 | 6.75 | -0.65 |
| Diameter, in | 31.80 | 31.50 | -0.30 (-0.9%) |
| Circumference, in | 99.9 | 99.0 | -0.9 |
| Revs per mile | 634 | 640 | +6 (+0.9%) |
Fitting 245/70R18 instead of 235/80R17
Within the usual 3% diameter guideline.
- Needs 18 in wheels.
- Shorter sidewall: 0.6 in less.
Cars with 245/70R18
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