Comparison
215/55 R16 vs 265/40 R18
Plus-sizing from 215/55 R16 to 265/40 R18 keeps overall diameter close to factory while opening room for a larger 18-inch wheel. This wheel and tire pairing moves rolling diameter well outside the usual OEM tolerance. Indicated speed will drift far enough that recalibration is worth considering. Less sidewall flex usually translates to crisper turn-in and a slightly stiffer ride over rough pavement. 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: 265/40 R18 is 26.3 mm taller than 215/55 R16, shifting the speedometer by +4.09%.
Current Tire
New Tire
Ground line · scaled comparison
Slight Difference
Within ±5% — usable, recalibration recommended
Diameter change
+26.3 mm
4.09%
Speedometer at 100
104.1 km/h
+4.09% error
Ground clearance
+13.2 mm
ride height delta
Sidewall change
-12.3 mm
revs/km: 475.7
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/compare/215-55-r16-vs-265-40-r18Detailed comparison
| Metric | 215/55 R16 | 265/40 R18 | Difference |
|---|---|---|---|
| Overall diameter | 642.9 mm | 669.2 mm | +26.3 mm (+4.09%) |
| Sidewall height | 118.3 mm | 106.0 mm | -12.3 mm |
| Circumference | 2.020 m | 2.102 m | +82.6 mm |
| Revs / km | 495.1 | 475.7 | -19.5 |
| Ground clearance | reference | +13.2 mm | +13.2 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 104.1 km/h | +4.09 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 104.1 km/h after switching to 265/40 R18 — a +4.09% 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 +13.2 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
215/55 R16
Back to
265/40 R18
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