Comparison
195/60 R16 vs 255/40 R18
255/40 R18 is a plus-2 alternative to 195/60 R16 — the bigger wheel shows through a thinner sidewall. This swap swings rolling diameter far enough to feel on the road. Expect a more planted steering feel, at the cost of some of the cushioning a taller sidewall provides.
The speedometer error is noticeable and may warrant a recalibration if you rely on indicated speed. 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: 255/40 R18 is 20.8 mm taller than 195/60 R16, shifting the speedometer by +3.25%.
Current Tire
New Tire
Ground line · scaled comparison
Slight Difference
Within ±5% — usable, recalibration recommended
Diameter change
+20.8 mm
3.25%
Speedometer at 100
103.2 km/h
+3.25% error
Ground clearance
+10.4 mm
ride height delta
Sidewall change
-15.0 mm
revs/km: 481.4
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/compare/195-60-r16-vs-255-40-r18Detailed comparison
| Metric | 195/60 R16 | 255/40 R18 | Difference |
|---|---|---|---|
| Overall diameter | 640.4 mm | 661.2 mm | +20.8 mm (+3.25%) |
| Sidewall height | 117.0 mm | 102.0 mm | -15.0 mm |
| Circumference | 2.012 m | 2.077 m | +65.3 mm |
| Revs / km | 497.0 | 481.4 | -15.6 |
| Ground clearance | reference | +10.4 mm | +10.4 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 103.2 km/h | +3.25 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 103.2 km/h after switching to 255/40 R18 — a +3.25% 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 +10.4 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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195/60 R16
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255/40 R18
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