Comparison
225/50 R18 vs 255/45 R19
Plus-sizing from 225/50 R18 to 255/45 R19 keeps overall diameter close to factory while opening room for a larger 19-inch wheel. This wheel and tire pairing moves rolling diameter well outside the usual OEM tolerance. The speedometer error is noticeable and may warrant a recalibration if you rely on indicated speed. The shorter sidewall gives the tire a firmer, more responsive feel and sharpens steering input. The 3–5% diameter gap puts this in caution territory: doable on many cars, but verify clearance and consider recalibration.
TakeA solid pick for drivers chasing a more aggressive stance without abandoning OEM rolling diameter.
Quick math: 255/45 R19 is 29.9 mm taller than 225/50 R18, shifting the speedometer by +4.38%.
Current Tire
New Tire
Ground line · scaled comparison
Slight Difference
Within ±5% — usable, recalibration recommended
Diameter change
+29.9 mm
4.38%
Speedometer at 100
104.4 km/h
+4.38% error
Ground clearance
+14.9 mm
ride height delta
Sidewall change
+2.3 mm
revs/km: 447.0
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/compare/225-50-r18-vs-255-45-r19Detailed comparison
| Metric | 225/50 R18 | 255/45 R19 | Difference |
|---|---|---|---|
| Overall diameter | 682.2 mm | 712.1 mm | +29.9 mm (+4.38%) |
| Sidewall height | 112.5 mm | 114.8 mm | +2.3 mm |
| Circumference | 2.143 m | 2.237 m | +93.9 mm |
| Revs / km | 466.6 | 447.0 | -19.6 |
| Ground clearance | reference | +14.9 mm | +14.9 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 104.4 km/h | +4.38 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 255/45 R19 — a +4.38% 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 +14.9 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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225/50 R18
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255/45 R19
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