Comparison
205/55 R16 vs 225/45 R18
225/45 R18 is a plus-2 alternative to 205/55 R16 — the bigger wheel shows through a thinner sidewall. This sizing approach noticeably changes overall diameter compared to OEM. The shorter sidewall gives the tire a firmer, more responsive feel and sharpens steering input.
Indicated speed will drift far enough that recalibration is worth considering. Diameter delta falls in the cautious 3–5% range, where speedometer recalibration and a careful clearance check are worth doing.
TakeCommon upgrade for sportier handling and a tighter wheel-gap look on the same vehicle.
Quick math: 225/45 R18 is 27.8 mm taller than 205/55 R16, shifting the speedometer by +4.40%.
Current Tire
New Tire
Ground line · scaled comparison
Slight Difference
Within ±5% — usable, recalibration recommended
Diameter change
+27.8 mm
4.40%
Speedometer at 100
104.4 km/h
+4.40% error
Ground clearance
+13.9 mm
ride height delta
Sidewall change
-11.5 mm
revs/km: 482.5
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/compare/205-55-r16-vs-225-45-r18Detailed comparison
| Metric | 205/55 R16 | 225/45 R18 | Difference |
|---|---|---|---|
| Overall diameter | 631.9 mm | 659.7 mm | +27.8 mm (+4.40%) |
| Sidewall height | 112.8 mm | 101.3 mm | -11.5 mm |
| Circumference | 1.985 m | 2.073 m | +87.3 mm |
| Revs / km | 503.7 | 482.5 | -21.2 |
| Ground clearance | reference | +13.9 mm | +13.9 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 225/45 R18 — 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 +13.9 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.
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205/55 R16
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225/45 R18
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