Comparison
225/55 R16 vs 235/45 R18
Going from 225/55 R16 to 235/45 R18 steps up to a 18-inch rim while trimming sidewall to stay near OEM rolling diameter. This wheel and tire pairing shifts overall diameter slightly from OEM. The speedometer offset is small but measurable; worth keeping in mind if you watch the dash closely. The shorter sidewall gives the tire a firmer, more responsive feel and sharpens steering input. 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: 235/45 R18 is 14.8 mm taller than 225/55 R16, shifting the speedometer by +2.26%.
Current Tire
New Tire
Ground line · scaled comparison
Excellent Fit
Within ±3% — safe for daily driving
Diameter change
+14.8 mm
2.26%
Speedometer at 100
102.3 km/h
+2.26% error
Ground clearance
+7.4 mm
ride height delta
Sidewall change
-18.0 mm
revs/km: 476.0
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/compare/225-55-r16-vs-235-45-r18Detailed comparison
| Metric | 225/55 R16 | 235/45 R18 | Difference |
|---|---|---|---|
| Overall diameter | 653.9 mm | 668.7 mm | +14.8 mm (+2.26%) |
| Sidewall height | 123.8 mm | 105.8 mm | -18.0 mm |
| Circumference | 2.054 m | 2.101 m | +46.5 mm |
| Revs / km | 486.8 | 476.0 | -10.8 |
| Ground clearance | reference | +7.4 mm | +7.4 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 102.3 km/h | +2.26 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 102.3 km/h after switching to 235/45 R18 — a +2.26% 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 +7.4 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.
Back to
225/55 R16
Back to
235/45 R18
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