245/50R17 vs 275/40R18 tire size
275/40R18 vs 245/50R17, diameter
Same diameter
- Speedometer
- 60.0 mph
- At a true 60 mph
- Diameter
- 26.66 in
- Was 26.65 in
- Revs per mile
- 756
- Was 757
- 3% guideline
- Within
Car built for 245/50R17, now on 275/40R18.
245/50R17 and 275/40R18
| Measure | 245/50R17 | 275/40R18 | Difference |
|---|---|---|---|
| Width, mm | 245 | 275 | +30 |
| Sidewall, % of width | 50 | 40 | -10 |
| Rim, in | 17 | 18 | +1 |
| Section height, in | 4.82 | 4.33 | -0.49 |
| Diameter, in | 26.65 | 26.66 | +0.02 (+0.1%) |
| Circumference, in | 83.7 | 83.8 | +0.0 |
| Revs per mile | 757 | 756 | -0 (-0.1%) |
Fitting 275/40R18 instead of 245/50R17
Within the usual 3% diameter guideline.
- Needs 18 in wheels.
- 30 mm wider. Check rubbing at full lock.
Cars with 275/40R18
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