Comparison
205/60 R16 vs 225/40 R18
225/40 R18 is a plus-2 alternative to 205/60 R16 — the bigger wheel shows through a thinner sidewall. This tire combination moves rolling diameter a touch off the original spec. 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. Diameter change stays inside the conservative ±3% safety window — an OEM-safe fitment on most vehicles.
TakeA solid pick for drivers chasing a more aggressive stance without abandoning OEM rolling diameter.
Quick math: 225/40 R18 is 15.2 mm shorter than 205/60 R16, shifting the speedometer by -2.33%.
Current Tire
New Tire
Ground line · scaled comparison
Excellent Fit
Within ±3% — safe for daily driving
Diameter change
-15.2 mm
-2.33%
Speedometer at 100
97.7 km/h
-2.33% error
Ground clearance
-7.6 mm
ride height delta
Sidewall change
-33.0 mm
revs/km: 499.5
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/compare/205-60-r16-vs-225-40-r18Detailed comparison
| Metric | 205/60 R16 | 225/40 R18 | Difference |
|---|---|---|---|
| Overall diameter | 652.4 mm | 637.2 mm | -15.2 mm (-2.33%) |
| Sidewall height | 123.0 mm | 90.0 mm | -33.0 mm |
| Circumference | 2.050 m | 2.002 m | -47.8 mm |
| Revs / km | 487.9 | 499.5 | +11.6 |
| Ground clearance | reference | -7.6 mm | -7.6 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 97.7 km/h | -2.33 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 97.7 km/h after switching to 225/40 R18 — a -2.33% 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 -7.6 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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205/60 R16
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225/40 R18
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