Comparison
245/45 R18 vs 275/40 R19
Switching from 245/45 R18 to 275/40 R19 is a plus-1 upgrade that wraps a shorter sidewall around a larger 19-inch wheel. This setup swings rolling diameter far enough to feel on the road. Indicated speed will drift far enough that recalibration is worth considering. Expect a more planted steering feel, at the cost of some of the cushioning a taller sidewall provides. 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: 275/40 R19 is 24.9 mm taller than 245/45 R18, shifting the speedometer by +3.67%.
Current Tire
New Tire
Ground line · scaled comparison
Slight Difference
Within ±5% — usable, recalibration recommended
Diameter change
+24.9 mm
3.67%
Speedometer at 100
103.7 km/h
+3.67% error
Ground clearance
+12.4 mm
ride height delta
Sidewall change
-0.3 mm
revs/km: 453.0
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/compare/245-45-r18-vs-275-40-r19Detailed comparison
| Metric | 245/45 R18 | 275/40 R19 | Difference |
|---|---|---|---|
| Overall diameter | 677.7 mm | 702.6 mm | +24.9 mm (+3.67%) |
| Sidewall height | 110.3 mm | 110.0 mm | -0.3 mm |
| Circumference | 2.129 m | 2.207 m | +78.2 mm |
| Revs / km | 469.7 | 453.0 | -16.6 |
| Ground clearance | reference | +12.4 mm | +12.4 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 103.7 km/h | +3.67 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 103.7 km/h after switching to 275/40 R19 — a +3.67% 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 +12.4 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.
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245/45 R18
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275/40 R19
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