Comparison
215/50 R16 vs 225/40 R18
Plus-sizing from 215/50 R16 to 225/40 R18 keeps overall diameter close to factory while opening room for a larger 18-inch wheel. This sizing approach shifts overall diameter slightly from OEM. Less sidewall flex usually translates to crisper turn-in and a slightly stiffer ride over rough pavement.
The speedometer offset is small but measurable; worth keeping in mind if you watch the dash closely. Overall the swap sits inside the safe ±3% diameter window, so ABS, traction control and gearing behave normally.
TakeCommon upgrade for sportier handling and a tighter wheel-gap look on the same vehicle.
Quick math: 225/40 R18 is 15.8 mm taller than 215/50 R16, shifting the speedometer by +2.54%.
Current Tire
New Tire
Ground line · scaled comparison
Excellent Fit
Within ±3% — safe for daily driving
Diameter change
+15.8 mm
2.54%
Speedometer at 100
102.5 km/h
+2.54% error
Ground clearance
+7.9 mm
ride height delta
Sidewall change
-17.5 mm
revs/km: 499.5
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/compare/215-50-r16-vs-225-40-r18Detailed comparison
| Metric | 215/50 R16 | 225/40 R18 | Difference |
|---|---|---|---|
| Overall diameter | 621.4 mm | 637.2 mm | +15.8 mm (+2.54%) |
| Sidewall height | 107.5 mm | 90.0 mm | -17.5 mm |
| Circumference | 1.952 m | 2.002 m | +49.6 mm |
| Revs / km | 512.2 | 499.5 | -12.7 |
| Ground clearance | reference | +7.9 mm | +7.9 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 102.5 km/h | +2.54 km/h |
Verdict: excellent
Within ±3% — speedometer, ABS and traction control should behave normally.
Speedometer impact
At a true 100 km/h, your dashboard will read 102.5 km/h after switching to 225/40 R18 — a +2.54% 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 +7.9 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.
Back to
215/50 R16
Back to
225/40 R18
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