Comparison
215/55 R16 vs 235/45 R18
Switching from 215/55 R16 to 235/45 R18 is a plus-2 upgrade that wraps a shorter sidewall around a larger 18-inch wheel. This sizing approach swings rolling diameter far enough to feel on the road.
The speedometer error is noticeable and may warrant a recalibration if you rely on indicated speed. Less sidewall flex usually translates to crisper turn-in and a slightly stiffer ride over rough pavement. More tread on the ground tends to improve dry grip and stance, with a small fuel-economy and clearance tradeoff. Many drivers pick this direction primarily for appearance — the bigger rim simply looks more aggressive. Diameter delta falls in the cautious 3–5% range, where speedometer recalibration and a careful clearance check are worth doing.
TakeA solid pick for drivers chasing a more aggressive stance without abandoning OEM rolling diameter.
Quick math: 235/45 R18 is 25.8 mm taller than 215/55 R16, shifting the speedometer by +4.01%.
Current Tire
New Tire
Ground line · scaled comparison
Slight Difference
Within ±5% — usable, recalibration recommended
Diameter change
+25.8 mm
4.01%
Speedometer at 100
104.0 km/h
+4.01% error
Ground clearance
+12.9 mm
ride height delta
Sidewall change
-12.5 mm
revs/km: 476.0
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/compare/215-55-r16-vs-235-45-r18Detailed comparison
| Metric | 215/55 R16 | 235/45 R18 | Difference |
|---|---|---|---|
| Overall diameter | 642.9 mm | 668.7 mm | +25.8 mm (+4.01%) |
| Sidewall height | 118.3 mm | 105.8 mm | -12.5 mm |
| Circumference | 2.020 m | 2.101 m | +81.1 mm |
| Revs / km | 495.1 | 476.0 | -19.1 |
| Ground clearance | reference | +12.9 mm | +12.9 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 104.0 km/h | +4.01 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 104.0 km/h after switching to 235/45 R18 — a +4.01% 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 +12.9 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
215/55 R16
Back to
235/45 R18
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