Comparison
235/55 R17 vs 225/45 R18
Compared to 235/55 R17, 225/45 R18 is 30.6 mm shorter and changes the speedometer reading by -4.43%.
Current Tire
235/55R17
New Tire
225/45R18
235/55 R17
225/45 R18
Ground line · scaled comparison
Slight Difference
Within ±5% — usable, recalibration recommended
Diameter change
-30.6 mm
-4.43%
Speedometer at 100
95.6 km/h
-4.43% error
Ground clearance
-15.3 mm
ride height delta
Sidewall change
-28.0 mm
revs/km: 482.5
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/compare/235-55-r17-vs-225-45-r18Detailed comparison
| Metric | 235/55 R17 | 225/45 R18 | Difference |
|---|---|---|---|
| Overall diameter | 690.3 mm | 659.7 mm | -30.6 mm (-4.43%) |
| Sidewall height | 129.3 mm | 101.3 mm | -28.0 mm |
| Circumference | 2.169 m | 2.073 m | -96.1 mm |
| Revs / km | 461.1 | 482.5 | +21.4 |
| Ground clearance | reference | -15.3 mm | -15.3 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 95.6 km/h | -4.43 km/h |
Verdict: warning
Between 3% and 5% — noticeable speedometer drift; recalibration may be advisable.
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235/55 R17
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225/45 R18