Comparison
225/45 R18 vs 245/40 R19
Switching from 225/45 R18 to 245/40 R19 is a plus-1 upgrade that wraps a shorter sidewall around a larger 19-inch wheel. This sizing approach shifts overall diameter slightly from OEM. The shorter sidewall gives the tire a firmer, more responsive feel and sharpens steering input.
The speedometer offset is small but measurable; worth keeping in mind if you watch the dash closely. Diameter change stays inside the conservative ±3% safety window — an OEM-safe fitment on most vehicles.
TakeA solid pick for drivers chasing a more aggressive stance without abandoning OEM rolling diameter.
Quick math: 245/40 R19 is 18.9 mm taller than 225/45 R18, shifting the speedometer by +2.86%.
Current Tire
New Tire
Ground line · scaled comparison
Excellent Fit
Within ±3% — safe for daily driving
Diameter change
+18.9 mm
2.86%
Speedometer at 100
102.9 km/h
+2.86% error
Ground clearance
+9.4 mm
ride height delta
Sidewall change
-3.3 mm
revs/km: 469.1
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/compare/225-45-r18-vs-245-40-r19Detailed comparison
| Metric | 225/45 R18 | 245/40 R19 | Difference |
|---|---|---|---|
| Overall diameter | 659.7 mm | 678.6 mm | +18.9 mm (+2.86%) |
| Sidewall height | 101.3 mm | 98.0 mm | -3.3 mm |
| Circumference | 2.073 m | 2.132 m | +59.4 mm |
| Revs / km | 482.5 | 469.1 | -13.4 |
| Ground clearance | reference | +9.4 mm | +9.4 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 102.9 km/h | +2.86 km/h |
Verdict: excellent
Within ±3% — speedometer, ABS and traction control should behave normally.
Speedometer impact
At a true 100 km/h, your dashboard will read 102.9 km/h after switching to 245/40 R19 — a +2.86% 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 +9.4 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
225/45 R18
Back to
245/40 R19
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