Comparison
245/40 R19 vs 245/45 R19
Switching from 245/40 R19 to 245/45 R19 keeps the wheel but adds sidewall for extra cushioning. This swap noticeably changes overall diameter compared to OEM. Extra sidewall absorbs impacts more readily — a sensible bias for daily commuting and broken pavement.
Indicated speed will drift far enough that recalibration is worth considering. Diameter delta falls in the cautious 3–5% range, where speedometer recalibration and a careful clearance check are worth doing.
TakeA comfort-leaning direction that's easier on wheels and suspension over rough surfaces.
Quick math: 245/45 R19 is 24.5 mm taller than 245/40 R19, shifting the speedometer by +3.61%.
Current Tire
New Tire
Ground line · scaled comparison
Slight Difference
Within ±5% — usable, recalibration recommended
Diameter change
+24.5 mm
3.61%
Speedometer at 100
103.6 km/h
+3.61% error
Ground clearance
+12.3 mm
ride height delta
Sidewall change
+12.3 mm
revs/km: 452.7
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/compare/245-40-r19-vs-245-45-r19Detailed comparison
| Metric | 245/40 R19 | 245/45 R19 | Difference |
|---|---|---|---|
| Overall diameter | 678.6 mm | 703.1 mm | +24.5 mm (+3.61%) |
| Sidewall height | 98.0 mm | 110.3 mm | +12.3 mm |
| Circumference | 2.132 m | 2.209 m | +77.0 mm |
| Revs / km | 469.1 | 452.7 | -16.3 |
| Ground clearance | reference | +12.3 mm | +12.3 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 103.6 km/h | +3.61 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 103.6 km/h after switching to 245/45 R19 — a +3.61% 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 +12.3 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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245/40 R19
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245/45 R19
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