Comparison
215/45 R18 vs 225/55 R17
Minus-sizing from 215/45 R18 to 225/55 R17 pairs a smaller 17-inch wheel with more rubber between the rim and road. This alternative fitment noticeably changes overall diameter compared to OEM. The speedometer error is noticeable and may warrant a recalibration if you rely on indicated speed. Extra sidewall absorbs impacts more readily — a sensible bias for daily commuting and broken pavement. The 3–5% diameter gap puts this in caution territory: doable on many cars, but verify clearance and consider recalibration.
TakeTypical choice for a dedicated winter or off-road setup where extra sidewall pays off.
Quick math: 225/55 R17 is 28.6 mm taller than 215/45 R18, shifting the speedometer by +4.40%.
Current Tire
New Tire
Ground line · scaled comparison
Slight Difference
Within ±5% — usable, recalibration recommended
Diameter change
+28.6 mm
4.40%
Speedometer at 100
104.4 km/h
+4.40% error
Ground clearance
+14.3 mm
ride height delta
Sidewall change
+27.0 mm
revs/km: 468.6
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/compare/215-45-r18-vs-225-55-r17Detailed comparison
| Metric | 215/45 R18 | 225/55 R17 | Difference |
|---|---|---|---|
| Overall diameter | 650.7 mm | 679.3 mm | +28.6 mm (+4.40%) |
| Sidewall height | 96.8 mm | 123.8 mm | +27.0 mm |
| Circumference | 2.044 m | 2.134 m | +89.8 mm |
| Revs / km | 489.2 | 468.6 | -20.6 |
| Ground clearance | reference | +14.3 mm | +14.3 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 104.4 km/h | +4.40 km/h |
Verdict: warning
Between 3% and 5% — noticeable speedometer drift; recalibration may be advisable.
Speedometer impact
At a true 100 km/h, your dashboard will read 104.4 km/h after switching to 225/55 R17 — a +4.40% offset. Use the speedometer error calculator to recheck for other indicated speeds, and the speedometer error guide for the full background.
Ground clearance change
The new tire's half-diameter changes ride height by +14.3 mm. Small differences are absorbed by suspension travel, but anything beyond ±10 mm can affect headlight aim, fender clearance and bump-stop margin. See the plus-sizing guide before committing.
Back to
215/45 R18
Back to
225/55 R17
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