235/45R17 vs 205/45R18 tire size
205/45R18 vs 235/45R17, diameter
-0.2% shorter
- Speedometer
- 60.1 mph
- At a true 60 mph
- Diameter
- 25.26 in
- Was 25.33 in
- Revs per mile
- 798
- Was 796
- 3% guideline
- Within
Car built for 235/45R17, now on 205/45R18.
235/45R17 and 205/45R18
| Measure | 235/45R17 | 205/45R18 | Difference |
|---|---|---|---|
| Width, mm | 235 | 205 | -30 |
| Sidewall, % of width | 45 | 45 | 0 |
| Rim, in | 17 | 18 | +1 |
| Section height, in | 4.16 | 3.63 | -0.53 |
| Diameter, in | 25.33 | 25.26 | -0.06 (-0.2%) |
| Circumference, in | 79.6 | 79.4 | -0.2 |
| Revs per mile | 796 | 798 | +2 (+0.2%) |
Fitting 205/45R18 instead of 235/45R17
Within the usual 3% diameter guideline.
- Needs 18 in wheels.
- Shorter sidewall: 0.5 in less.
Cars with 235/45R17
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