Comparison
255/45 R19 vs 295/40 R20
Plus-sizing from 255/45 R19 to 295/40 R20 keeps overall diameter close to factory while opening room for a larger 20-inch wheel. This alternative fitment 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. Diameter delta falls in the cautious 3–5% range, where speedometer recalibration and a careful clearance check are worth doing.
TakeCommon upgrade for sportier handling and a tighter wheel-gap look on the same vehicle.
Quick math: 295/40 R20 is 31.9 mm taller than 255/45 R19, shifting the speedometer by +4.48%.
Current Tire
New Tire
Ground line · scaled comparison
Slight Difference
Within ±5% — usable, recalibration recommended
Diameter change
+31.9 mm
4.48%
Speedometer at 100
104.5 km/h
+4.48% error
Ground clearance
+16.0 mm
ride height delta
Sidewall change
+3.3 mm
revs/km: 427.8
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/compare/255-45-r19-vs-295-40-r20Detailed comparison
| Metric | 255/45 R19 | 295/40 R20 | Difference |
|---|---|---|---|
| Overall diameter | 712.1 mm | 744.0 mm | +31.9 mm (+4.48%) |
| Sidewall height | 114.8 mm | 118.0 mm | +3.3 mm |
| Circumference | 2.237 m | 2.337 m | +100.2 mm |
| Revs / km | 447.0 | 427.8 | -19.2 |
| Ground clearance | reference | +16.0 mm | +16.0 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 104.5 km/h | +4.48 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 104.5 km/h after switching to 295/40 R20 — a +4.48% 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 +16.0 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
255/45 R19
Back to
295/40 R20
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