Comparison
225/50 R18 vs 285/35 R20
285/35 R20 is a plus-2 alternative to 225/50 R18 — the bigger wheel shows through a thinner sidewall. This setup noticeably changes overall diameter compared to OEM. Indicated speed will drift far enough that recalibration is worth considering. 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.
TakeCommon upgrade for sportier handling and a tighter wheel-gap look on the same vehicle.
Quick math: 285/35 R20 is 25.3 mm taller than 225/50 R18, shifting the speedometer by +3.71%.
Current Tire
New Tire
Ground line · scaled comparison
Slight Difference
Within ±5% — usable, recalibration recommended
Diameter change
+25.3 mm
3.71%
Speedometer at 100
103.7 km/h
+3.71% error
Ground clearance
+12.6 mm
ride height delta
Sidewall change
-12.8 mm
revs/km: 449.9
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/compare/225-50-r18-vs-285-35-r20Detailed comparison
| Metric | 225/50 R18 | 285/35 R20 | Difference |
|---|---|---|---|
| Overall diameter | 682.2 mm | 707.5 mm | +25.3 mm (+3.71%) |
| Sidewall height | 112.5 mm | 99.8 mm | -12.8 mm |
| Circumference | 2.143 m | 2.223 m | +79.5 mm |
| Revs / km | 466.6 | 449.9 | -16.7 |
| Ground clearance | reference | +12.6 mm | +12.6 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 103.7 km/h | +3.71 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 103.7 km/h after switching to 285/35 R20 — a +3.71% 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 +12.6 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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285/35 R20
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