Comparison
265/50 R20 vs 285/60 R18
Switching from 265/50 R20 to 285/60 R18 steps down to a 18-inch wheel — a familiar move for winter and dedicated all-terrain sets. This tire combination 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 taller sidewall adds cushioning over potholes and rougher roads, with a softer overall ride. The 3–5% diameter gap puts this in caution territory: doable on many cars, but verify clearance and consider recalibration.
TakePractical direction for winter wheels, chains, or rougher pavement where cushioning matters.
Quick math: 285/60 R18 is 26.2 mm taller than 265/50 R20, shifting the speedometer by +3.39%.
Current Tire
New Tire
Ground line · scaled comparison
Slight Difference
Within ±5% — usable, recalibration recommended
Diameter change
+26.2 mm
3.39%
Speedometer at 100
103.4 km/h
+3.39% error
Ground clearance
+13.1 mm
ride height delta
Sidewall change
+38.5 mm
revs/km: 398.3
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/compare/265-50-r20-vs-285-60-r18Detailed comparison
| Metric | 265/50 R20 | 285/60 R18 | Difference |
|---|---|---|---|
| Overall diameter | 773.0 mm | 799.2 mm | +26.2 mm (+3.39%) |
| Sidewall height | 132.5 mm | 171.0 mm | +38.5 mm |
| Circumference | 2.428 m | 2.511 m | +82.3 mm |
| Revs / km | 411.8 | 398.3 | -13.5 |
| Ground clearance | reference | +13.1 mm | +13.1 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 103.4 km/h | +3.39 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 103.4 km/h after switching to 285/60 R18 — a +3.39% 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 +13.1 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
265/50 R20
Back to
285/60 R18
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