Comparison
215/45 R18 vs 245/35 R20
Plus-sizing from 215/45 R18 to 245/35 R20 keeps overall diameter close to factory while opening room for a larger 20-inch wheel. This swap noticeably changes overall diameter compared to OEM. The shorter sidewall gives the tire a firmer, more responsive feel and sharpens steering input.
The speedometer error is noticeable and may warrant a recalibration if you rely on indicated speed. 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: 245/35 R20 is 28.8 mm taller than 215/45 R18, shifting the speedometer by +4.43%.
Current Tire
New Tire
Ground line · scaled comparison
Slight Difference
Within ±5% — usable, recalibration recommended
Diameter change
+28.8 mm
4.43%
Speedometer at 100
104.4 km/h
+4.43% error
Ground clearance
+14.4 mm
ride height delta
Sidewall change
-11.0 mm
revs/km: 468.4
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/compare/215-45-r18-vs-245-35-r20Detailed comparison
| Metric | 215/45 R18 | 245/35 R20 | Difference |
|---|---|---|---|
| Overall diameter | 650.7 mm | 679.5 mm | +28.8 mm (+4.43%) |
| Sidewall height | 96.8 mm | 85.8 mm | -11.0 mm |
| Circumference | 2.044 m | 2.135 m | +90.5 mm |
| Revs / km | 489.2 | 468.4 | -20.7 |
| Ground clearance | reference | +14.4 mm | +14.4 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 104.4 km/h | +4.43 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 104.4 km/h after switching to 245/35 R20 — a +4.43% 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 +14.4 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
215/45 R18
Back to
245/35 R20
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